Australia's level of household debt is climbing ever higher, reaching the fourth-highest level in the world.

And this fact is reflected by the increasing calls for help to Australia's debt help services.

National Debt Helpline finance counsellor Claire Tacon said the helpline had received a record number of calls last year.

"The figures show that people are doing it tough," she told A Current Affair.

Last month, the centre received more than 18,000 calls - 12 per cent higher than the same period last year.

"Financial counsellors can give you advice on how to negotiate with creditors, talk you through your legal rights, give you advice on how to make complaints to ombudsmen schemes," she said.

She said the "absolute best thing" people struggling with debt could do was speak to an independent, free financial counsellor about their rights and options.

"Anyone can be impacted by debt," she said.

Young mum Louise said she had found bills and expenses were growing.

On one income, she and her husband can struggle to cope with the medical costs, swimming lessons and childcare fees they have, on top of the normal bills.

"We're so scared we're going to get a bill we can't afford," she said.

"Cost of living is going up but wages aren't, and that's really tough for a struggling family."

Mother-of-three Shelly is also worried about getting bogged down in debt.

She said her family lived week to week, often relying on credit cards to get them through.

"It's literally: pay all the bills, make ends meet, make sure you make it through the week, then it's nearly payday again," she said.

Statistics show the average Australian household has about $220,000 worth of debt, with most of that being "good debt" - such as money owed for a mortgage.

But the average family still owes about $20,000 of "bad debt" - including things like credit cars and car loans.

Finder finance expert Kate Browne said in many cases, our spending had outstripped our income.

"The first thing is to try to consolidate some of your debt - so if you have multiple credit card debts for example, look at moving it to a single credit card," she said.

"There are zero balance transfer cards out there where your debt comes over at a zero-interest rate.

"Speak to your bank, see if they can offer you a better option - all of this is going to help you reduce these ongoing costs and get the debt under control."

Visit the National Debt Helpline online here.

The body of a man has been found in Perth's Swan River.

Police say the man was found about 1pm today along the foreshore in Burswood near the Matagarup Bridge as dozens of people lined the river’s banks to watch a national water-skiing competition.

A driver of one of the boat’s involved in the competition noticed the man’s body.

He appears to be aged 30 to 40 years and is of possible Asian descent, a spokeswoman said.

"The identity of the man is unknown and as such his family have not been notified," she said.

Police are investigating if any foul play was involved.

New vision shows two of the most notorious prisoners in New South Wales going head to head in an apparent struggle for power.

The video shows convicted killer Bassam Hamzy being repeatedly punched by Talal Alameddine inside a yard at Goulburn Supermax prison last October.

Hamzy was jailed after he shot dead Kris Toumazis in Paddington in 1998, wounded one friend and shot at another.

He converted to Muslim while behind bars and founded the violent Brothers 4 Life gang, making  460 calls a day on a mobile phone which was moved between cells using dental floss.

He is now serving a combined maximum sentence of more than 40 years.

Alameddine was arrested in 2015 and jailed for a maximum of 17 years for supplying the gun which was used to execute police accountant Curtis Cheng in the Parramatta Police Headquarters terror attack.

Both have now been charged with affray over the punch last October but are yet to enter pleas.

They face a maximum of ten years behind bars on top of the terms they’re already serving.

A toddler who was last seen in regional New South Wales two days ago has been found in Queensland.

The 22-month-old girl went missing from Grafton on Monday and police had launched a large-scale search for her.

She was found in Southport at 10.30pm today.

“Police would like to thank the public and members of the media for their assistance in relation to this matter,” NSW police said in a statement.

An investigation is underway.

Unified in grief and determined to act, New Zealand's politicians have almost unanimously voted to ban high-powered guns in response to the Christchurch mosque shootings.

Less than four weeks after the terror attack on mosques that killed 50, the country's parliament on Wednesday afternoon overwhelmingly voted for a ban on a range of semi-automatic weapons and modifications, passing the bill 119 votes-to-one at its third and final reading.

In her speech to the House, Prime Minister Jacinda Ardern said she vividly recalled the moment she knew change was coming.

"[The police commissioner] described to me the nature of the weapons that had been used in this terror attack. And then he described to me they had been obtained legally," she said.

"I could not fathom how weapons that could cause such destruction and large-scale death could have been obtained legally in this country."

She appeared near tears as she spoke of the attack's victims and survivors during.

"We are ultimately here because 50 people died and they do not have a voice. We in this house are their voice."

The conservative opposition National Party backed the bill at all stages, despite some farmers this week expressing frustration at a lack of exemptions for pest control - and on Wednesday did the same in a rare moment of unity.

"To the families of our missing 50 and those who were injured, I trust you will look at us as an institution and say we delivered here today," National MP Andrew Bayly said.

Standing alone against the ban was the libertarian Act party's sole MP, David Seymour, who lamented the pace the legislation was passed, despite agreeing some change was needed.

While a small and vocal gun lobby had echoed those concerns, a wave of public support has swept the laws through at an almost unprecedented speed.

Ardern evoked Australia's swift response to the Port Arthur massacre as she dismissed calls for delay.

"An argument about process is an argument to do nothing... the first politician I ever heard say that in relation to gun laws was John Howard," she told parliament.

"You either believe that in New Zealand these weapons have a place or you do not."

Wednesday's law change was announced six days after the March 15 attack, with Ardern promising the weapons used in the shooting would be taken out of public hands.

The bill was introduced into the house last week an single day of public hearings was held and officials worked through 13,000 written submissions in days.

But even before the new laws were introduced, politicians made it clear more would follow.

The 28-year-old Australian man arrested after the attack is alleged to have bought his weapons legally before modifying them, and politicians will consider whether licensing rules need tightening.

They'll also consider a comprehensive gun register.

While about 1.5 million guns are thought to be in the country, a lack of registration means authorities have no idea how many weapons are expected to be handed back during an amnesty and gun buyback - the first details of which were unveiled on Wednesday - or how much the program may cost.

While politicians held their vote on Wednesday, volunteers in Christchurch began removing an enormous pile of tributes and flowers that has built up at the city's Botanic Gardens.

The 150-metre-long collection will be sorted and taken to families and mosques.

More than a dozen of those hurt remain in hospital.

Scientists have revealed the first image ever made of a black hole, depicting its hot, shadowy edges where light bends around itself in a cosmic funhouse effect.

Assembling data gathered by eight radio telescopes around the world, astronomers created the picture showing the violent neighbourhood around a supermassive black hole, the light-sucking monsters of the universe theorised by Einstein more than a century ago and confirmed by observations for decades.

It looked like a flaming orange, yellow and black ring.

"We have seen what we thought was unseeable. We have seen and taken a picture of a black hole. Here it is," said Sheperd Doeleman of Harvard.

Jessica Dempsey, a co-discoverer and deputy director of the East Asian Observatory in Hawaii, said it reminded her of the powerful flaming Eye of Sauron from the "Lord of the Rings" trilogy.

Unlike smaller black holes that come from collapsed stars, supermassive black holes are mysterious in origin. Situated at the centre of most galaxies, including ours, they are so dense that nothing, not even light, can escape their gravitational pull. This one's "event horizon" — the point of no return around it, where light and matter begin to fall inexorably into the abyss — is as big as our entire solar system.

Three years ago, scientists using an extraordinarily sensitive observing system heard the sound of two much smaller black holes merging to create a gravitational wave, as Albert Einstein predicted. The new image, published in the Astrophysical Journal Letters and announced around the world in several news conferences, adds light to that sound.

Outside scientists suggested the achievement could be worthy of a Nobel Prize, just like the gravitational wave discovery.

While much around a black hole falls into a death spiral and is never to be seen again, the new image captures "lucky gas and dust" circling at just far enough to be safe and seen millions of years later on Earth, Dempsey said.

Taken over four days when astronomers had "to have the perfect weather all across the world and literally all the stars had to align," the image helps confirm Einstein's general relativity theory, Dempsey said. Einstein a century ago even predicted the symmetrical shape that scientists just found, she said.

"It's circular, but on one side the light is brighter," Dempsey said. That's because that light is approaching Earth.

The measurements are taken at a wavelength the human eye cannot see, so the astronomers added colour to the image. They chose "exquisite gold because this light is so hot," Dempsey said. "Making it these warm gold and oranges makes sense."

What the image shows is gas heated to millions of degrees by the friction of ever-stronger gravity, scientists said. And that gravity creates a funhouse effect where you see light from both behind the black hole and behind you as the light curves and circles around the black hole itself, said astronomer Avi Loeb, director of the Black Hole Initiative at Harvard. (The lead scientists in the discovery are from Harvard, but Loeb was not involved.)

The project cost $50 million to $60 million, with $26 million of that coming from the National Science Foundation.

Johns Hopkins astrophysicist Ethan Vishniac, who was not part of the discovery team but edits the journal where the research was published, pronounced the image "an amazing technical achievement" that "gives us a glimpse of gravity in its most extreme manifestation."

He added: "Pictures from computer simulations can be very pretty, but there's literally nothing like a picture of the real universe, however fuzzy and monochromatic."

"It's just seriously cool," said John Kormendy, a University of Texas astronomer who wasn't part of the discovery team. "To see the stuff going down the tubes, so to speak, to see it firsthand. The mystique of black holes in the community is very substantial. That mystique is going to be made more real."

There is a myth that says a black hole would rip you apart, but Loeb and Kormendy said the one pictured is so big, someone could fall into it and not be torn to pieces. But the person would never be seen from again.

Black holes are "like the walls of a prison. Once you cross it, you will never be able to get out and you will never be able to communicate," Loeb said.

The first image is of a black hole in a galaxy called M87 that is about 53 million light years from Earth. One light year is 5.9 trillion miles, or 9.5 trillion kilometres. This black hole is about 6 billion times the mass of our sun.

The telescope data was gathered by the Event Horizon Telescope two years ago, but it took so long to complete the image because it was a massive undertaking, involving about 200 scientists, supercomputers and hundreds of terabytes of data delivered worldwide by plane.

The team looked at two supermassive black holes, the M87 and the one at the centre of our own Milky Way galaxy. The one in our galaxy is closer but much smaller, so they both look the same size in the sky. But the more distant one was easier to take pictures of because it rotates more slowly.

"We've been hunting this for a long time," Dempsey said. "We've been getting closer and closer with better technology."

Prime Minister Scott Morrison has touched down in Canberra with the intention of meeting the Governor-General in the morning to call an election.

9News has confirmed Mr Morrison will name May 18 as the election date.

Mr Morrison flew into the Nation's Capital from Melbourne late last night.

READ MORE: Key seats to watch in federal election

Earlier this evening, the Mr Morrison posted a video to his social media accounts, appearing to kick off the election campaign.

Using his family as the focal point, the almost two-minute video showed Mr Morrison talking about “my vision for Australia”.

“I’m proud of how far our country has come over the past few years,” the post read.

“And I know there is still more work for us to do to make life better for all Australians. My vision for Australia is about everyone having the chance to realise their full potential.”

The expected announcement comes a week after a populist-themed surplus budget, which was aimed at bolstering the government's support ahead of the vote.

The election campaign comes as the two most recent opinion polls point to a Labor victory.

On a two-party preferred basis, Ipsos had Labor leading 53-47 and Newspoll put the gap at 52-48, despite the poll being Mr Morrison’s best result since seizing the prime ministership.

Mr Morrison will be battling for a majority government after the hung parliament which has hamstrung many of the government's policies.

But the Coalition is fending off challenges from all sides, with the Greens, Independents, One Nation and Labor all likely to snatch seats.

Both major parties have been engaged in a phantom election campaign for months, with Opposition Leader Bill Shorten hammering the government on low wages growth.

Mr Morrison meanwhile has used Labor's proposed changes to negative gearing as a cudgel against them.

The government will now go into caretaker mode, with no more parliament scheduled under after election day.

FEDERAL ELECTION: HOW WE GET THERE

With the budget brought forward to April 2, the prime minister is likely to set the poll for May 18.

Once the governor-general issues writs for an election, the government is in caretaker mode. That means it can't make decisions without the acquiescence of the opposition. 

With the addition of a new ACT seat, 151 MPs will be elected along with and half of Australia's 76 senators. 

To win majority government either party needs to win 76 seats in the House of Representatives. 

The coalition goes into the election holding 74 lower house seats; Labor has 69. 

Labor needs to gain seven seats on a uniform swing of one per cent from the 2016 election. After a redrawing of electoral boundaries and the Wentworth by-election, the coalition starts notionally with 73 seats with Labor on 72.

ELECTION 2019 KEY POINTS

- Will be a half Senate and full House election, unlike the last election in 2016 when it was a double dissolution.

- Polls show Labor is the favourite, averaging just under 54 per cent of the two-party result.

- To be held under new House of Representatives seat boundaries.

- 151 seats instead of current 150, due to population growth

- Victoria (Fraser) and ACT (Bean) gain a seat. SA loses a seat (Port Adelaide; Sitting member Labor's Mark Butler to run in Hindmarsh instead)

- Liberal-Nationals government starts with 74 seats, Labor 69, 7 others - four independent (Wilkie, McGowan, Phelps, Banks), one Centre Alliance (Sharkie), one Green (Bandt), one Katter's Australian Party (Katter).]

- Under redrawn boundaries, Labor expected to start favourite in new seats in ACT and Victoria, giving it a two-seat head start.

- It is the first major electoral test for Prime Minister Scott Morrison. Last one in 2016 ended in a one-seat majority for the coalition under Malcolm Turnbull.

- Bill Shorten is longest serving opposition leader since Kim Beazley. His seat of Maribyrnong has been made more marginal due to boundary changes.

- Senate numbers (76 total): 31 coalition; 26 Labor; 9 Greens; 2 Pauline Hanson's One Nation; 2 Centre Alliance; 1 Liberal Democrats; 1 Derryn Hinch's Justice Party; 1 Australian Conservatives; 1 Katter's Australian Party; 1 United Australia Party; 1 Independent.

- Minor parties will find it harder to win or retain seats as there is a higher vote quota in the Senate than during the double-dissolution election.

- First time in four decades that the PM and Treasurer are working dads with young children. Last pair of this nature was Malcolm Fraser and John Howard.

A 430 million-year-old fossil has injected life into the classic “Cthulhu” sea monster myth as scientists use new technology to create 3D models of ancient underwater life.

The fossil, described as being “exceptionally preserved”, was pulled from the seabed in Herefordshire in the UK and measures just 3 centimetres wide.

It is believed to be one of the earliest sea cucumbers in existence, and when alive would have appeared “monstrous” to the miniscule aquatic life around it.

Palaeontologists from the US and the UK worked together to grind away the fossil, photographing it from hundreds of different angles to then digitally reconstruct the animal as a 3D model.

After discovering the cucumber’s numerous tentacles – which would have been used to capture food and crawl across the sea floor – the scientists named the new species as Sollasina Cthulhu, after the fictional sea monster created by author H.P Lovecraft.

Invented by Lovecraft in 1928, Cthulhu is an enormous octopus-like underwater entity that hibernates under the ocean and cultivates human anxiety on a subconscious level.

Dr Jeffrey Thompson, who co-authored the paper described Sollasina Cthulhu, said the discovery shed more light on the evolutionary timeline of sea slugs.

"We carried out a number of analyses to work out whether Sollasina was more closely related to sea cucumbers or sea urchins,” said Dr Thompson.

“To our surprise, the results suggest it was an ancient sea cucumber. This helps us understand the changes that occurred during the early evolution of the group, which ultimately gave rise to the slug-like forms we see today."

The slices of the ancient cucumber – as well as the 3D reconstruction of its living form – are currently being held at the Oxford University Museum of Natural History.

Researchers say a new device developed at Flinders University could be a "game changer" for sleep apnea sufferers.

The technology allows doctors to pinpoint the cause of the problem, improving patient outcomes.

"We're quite excited about what this could mean in theory it could be a game changer," Flinders University researcher Alex Wall said.

It's estimated up to seven per cent of people have sleep apnea.

It's a condition where airways become blocked causing sufferers to stop breathing repeatedly throughout the night.

"People with sleep apnea are at a much higher risk of not only falling asleep at the wheel but also having heart attacks, high blood pressure, lots of major health issues," Clinical Expert Professor Simon Carney said.

This new device, developed by researchers at Flinders University, could give doctors more insight into why it happens.

The catheter contains a micro camera which, when placed into the nostrils and down the throat, allows specialists to pinpoint where blockages are occurring while the patient is asleep.

"That will give us real time analysis of whats happening at every single area of the airway," Professor Carney said.

The device also has pressure and temperature sensors - data which can be used to determine the severity of the condition.

"There's nothing at the moment that has both pressure, temperature and the microcamera all in one," Mr Wall said.

Sleep apnea is one of the most rapidly rising public health issues affecting Australians of all ages.

Specialists say obesity is a major contributor.

It's hoped this world-first could lead to more effective, targeted treatments.

"It could make a big difference to patient outcomes," Mr Wall added.

"They won't need as big an operation, they'll be in less pain and less morbidity afterwards and everyone's happy," Professor Carney agreed.

Human trials will now be conducted in Adelaide and in Western Australia.

If successful, the device could be available for use in as little as three years.

Australians will go to the polls on May 18, after Prime Minister Scott Morrison ended speculation on when he would call a Federal election.

Morrison visited the governor-general this morning, requesting that federal parliament be dissolved so that voters can head to the polls.

Now the official date is known, we take a look at what you need to know about this election.

Key election dates:

April 11: Announcement of election and issue of writs

April 18: Close of electoral rolls (there are still 588,000 voters not enrolled)

April 23: Close of nominations

May 18: Election day

June 28: Return of writs

What happens now?

Once the governor-general issues the AEC with the writs for an election, the government is in caretaker mode. That means it can't make decisions without the acquiescence of the opposition.

With the addition of a new ACT seat, 151 MPs will be elected along with and half of Australia's 76 senators.

To win majority government either party needs to win 76 seats in the House of Representatives.

The coalition goes into the election holding 74 lower house seats; Labor has 69.

Labor needs to gain seven seats on a uniform swing of one per cent from the 2016 election. After a redrawing of electoral boundaries and the Wentworth by-election, the coalition starts notionally with 73 seats with Labor on 72.

Half of the seats in the 76-member Senate are up for grabs.

Who’s Australia’s preferred PM?

Opinion polls are pointing to the Liberal-National coalition losing power to Labor after five-and-a-half years in office.

Mr Morrison said there was much at stake at the election and only the coalition could deliver a strong economy and the dividends of that.

What would a Liberal/Nations government deliver?

Mr Morrison is spruiking the government's commitment to a strong economy, its plan for a budget surplus in 2019/20, commitment to low unemployment and more jobs as well as tax cuts.

"Keeping our economy strong is how we secure your future and your family's future. Keeping our economy strong ensures that we can secure your wage, your job, your business and, importantly, the business you are going to work for today."

The former immigration minister says Labor's approach to national security will weaken Australia's borders, and will no doubt ramp up his championing of Operation Sovereign Borders throughout the campaign.

"We will keep Australians safe as Liberal National governments always do, and we will keep our borders secure, as you know we will,” Morrison said.

The prime minister says having a strong economy means guaranteed funding for essential services Australians rely on, such as schools, hospitals, medicines, roads, aged care and disability care.

"All of these are now at record levels of funding that only a strong economy can guarantee into the future, not higher taxes."

As treasurer, Mr Morrison sought to crack down on the welfare system, with the aim of ensuring people who needed help the most received government assistance. As prime minister, this ambition has been translated into his "a fair go for those who have a go" motto.

"Part of the promise that we all keep, as Australians, is that we make a contribution and don't seek to take one."

What would a Labor government deliver?

In the first 100 days, Labor has claimed it would reverse the cut to Sunday penalty rates for 700,000 workers and legislate so penalty rates can never be arbitrarily reduced again.

It would introduce a national inquiry into post-secondary education.

It plans to hold a summit on indigenous children safety and have consultation on an indigenous voice to parliament.

Overall a Labor government claims it will establish a national integrity commission, a Climate policy includes 50 per cent renewable energy target by 2030 and introduce a NBN service guarantee to better protect consumers and businesses.

It would also restore funding to the ABC, post more federal police overseas to crack down on people smuggling, spend an extra $14 billion for public schools over a decade.

It would also introduce a two-year national preschool and kindy program, scrap upfront fees for skill-shortage TAFE courses, rebuild foreign aid budget and cap private health insurance price increases.

Labor is also promising a 10-year affordable housing plan, limit future negative gearing concessions to new housing and reduce the CGT discount from 50 per cent to 25 per cent push for the Fair Work Commission to consider ‘living wage’.

It also plans Indigenous recognition action plan and Stolen Generations compensation scheme.

With wires

Crime scene photos of a blood-stained police car and a body lying under a white sheet have been presented in the murder trial of Australian woman Justine Ruszczyk.

On the second day of the criminal trial against US police officer Mohamed Noor, a special agent took the witness stand to present forensic evidence.

Noor is charged with shooting and killing the Sydney bride-to-be in July 2017 after she rang 911 to report what she believed was a sexual assault behind her home.

9News US correspondent Alexis Daish, who is covering the trial, said the special agent, who has not been identified, is involved in investigating Noor.

Daish said the images, which were at times difficult to look at, included bloodstains on the left side of Noor’s police car.

The bloodstains were found on the same side of the car where Ruszczyk’s body was lying.

She said as well as the bloodstains, Daish said there were fingerprints.

“There were fingerprints on the back of this police car that were marked,” Daish said.

As well as fingerprints on the front bonnet there were also fingerprints on the back passenger window.

Daish said Ruszczyk’s family, who were also in the courtroom, at times, looked down, choosing not to look at the crime scene evidence which showed Ruszczyk’s body lying beside the police car under a white sheet.

The special agent is due to continue to give evidence in the trial tomorrow.

Yesterday, Ruszczyk’s fiancé Don Damond broke down in court as he spoke about the last phone call he had with Ruszczyk. He also revealed the nightmare phone call he made to her father telling him his daughter had been shot dead.

The court has heard Ruszczyk’s final words to Damond that night were: “OK, the police are here”.

Just one minute and 19 seconds after that call, Ruszcyk again spoke to Damond with the words “I’m dying” after she had been shot by Noor.

As part of his evidence, Damond told the court he had fallen in love with Ruszcyk’s the first time the pair met. He also shared with the court how he had proposed.

Damond also told the court he was in Las Vegas on a work trip when he received a call from police that Ruszczyk had been shot by a policeman.

“He broke down sobbing as Justine's father John when Don was having to tell John, her father back in Australia, that Justine had passed away,” Daish said.

Earlier, Noor’s patrol partner Officer Matthew Harrity, who was with Noor at the time of the shooting, told the court Ruszczyk “came up on us”.

“She just came up out of nowhere on the side of the thing… we both got spooked. I had my gun out... I didn’t fire and then Noor pulled out and fired,” Harrity told the court.

During an awkward moment in court, Ruszczyk’s family were left looking at each other in shock and disbelief when the defence lawyer referred to Justine as Janine.

Daish said it is clear the crux of the case will be about a supposed thump on the back of the police car.

She said the defence will be arguing that a thud was felt on the back of the police car, with the officers believing they were in a “classic ambush scenario”.

“It is the next split second that this case is all about,” AP quotes Noor’s defence lawyer Peter Wold as telling the court.

Lawyers for Noor, who was fired after being charged in the case and has never talked to investigators about what happened, argue that he used reasonable force to defend himself and his partner from a perceived threat.

However, prosecutors said there is no evidence he faced a threat that justified deadly force. They also plan to discredit the suggestions a thud was made on the patrol car.

Minnesota law allows police officers to use deadly force to protect themselves or their partners from death or great bodily harm. Prosecutors charged Noor with second-degree intentional murder, third-degree murder and second-degree manslaughter.

With wires

US Immigration and Customs Enforcement Acting Director Ron Vitiello will leave his leadership post at the end of the week.

His announcement, made in a letter sent to ICE employees today, comes after his nomination to lead the agency in a permanent position was suddenly pulled by the White House last week.

"I am writing to let you know that Friday, April 12, 2019, will be my last day as Acting Director of US Immigration and Customs Enforcement (ICE)," the letter said obtained by CNN.

"I would also like to express my deep thanks and gratitude for the opportunity to serve with our incredible workforce."

Vitiello, who appeared to be on the cusp of Senate confirmation, was nominated by President Donald Trump to head the agency in August last year.

He previously served as chief of the US Border Patrol and acting deputy commissioner of Customs and Border Protection.

President Donald Trump said last Friday that he wanted to go in a "tougher direction" - a move that came at the urging of White House senior adviser Stephen Miller.

"We're going in a little different direction. Ron's a good man but we're going in a tougher direction. We want to go in a tougher direction," Trump told reporters at the White House.

The surprise withdrawal of his nomination set off a week of uncertainty and major leadership change at the Department of Homeland Security, which oversees ICE.

By Sunday, Homeland Security Secretary Kirstjen Nielsen announced her resignation, and acting DHS Deputy Secretary Claire Grady today also announced her resignation.

A day after Ms Nielsen's resignation, it was revealed that US Secret Service director Randolph 'Tex' Alles will also be removed from his position.

The raft of culls from the White House has seen senior administration officials criticise the move.

"There is a near-systematic purge happening at the nation's second-largest national security agency," one senior administration official said.

At least two other DHS officials were also been named as possibly heading out the door.

The UK and European Union have agreed to a "flexible extension" of Brexit until October 31, European Council president Donald Tusk has confirmed.

The agreement was reached after more than six hours of talks at an emergency EU summit in Brussels.

British Prime Minister Theresa May had earlier said she wanted to move the Brexit date from Friday to June 30.

EU leaders spent a long dinner meeting wrangling over whether to save Britain from a precipitous and potentially calamitous Brexit, or to give the foot-dragging departing nation a shove over the edge.

May pleaded with the leaders to delay Britain's exit while the UK sorts out the mess that Brexit has become.

Some were sympathetic, but French President Emmanuel Macron struck a warning note.

"Nothing is decided," Macron said, insisting on "clarity" from May about what Britain wants.

"What's indispensable is that nothing should compromise the European project in the months to come," he said.

British lawmakers have rejected May's divorce deal three times, and attempts to forge a compromise with her political opponents have yet to bear fruit.

Earlier, many leaders said they were inclined to grant a Brexit delay, though Macron had reservations after hearing May speak. An official in the French president's office said the British leader hadn't offered "sufficient guarantees" to justify a long extension.

Macron was concerned that letting Britain stay too long would distract the EU from other issues — notably next month's European Parliament elections.

"The no-deal situation is a real option," said the official, who was not authorised to be publicly named according to presidential policy. "Putting in danger the functioning of Europe is not preferable to a no-deal."

Others suggested a longer delay would likely be needed, given the depth of Britain's political disarray.

Luxembourg Prime Minister Xavier Bettel said he hoped for "an intelligent extension".

"If it's a longer extension there is no lunch for free, so we need to know why," he said.

May signalled she would accept a longer extension, as long as it contained a get-out-early cause should Britain end its Brexit impasse.

"What is important is that any extension enables us to leave at the point at which we ratify the withdrawal agreement," May said as she arrived in Brussels.

Several months have passed since May and the EU struck a deal laying out the terms of Britain's departure and the outline of future relations. All that was needed was ratification by the British and European Parliaments.

But UK lawmakers rejected it — three times. As Britain's departure date of March 29 approached with no resolution in sight, the EU gave Britain until Friday to approve a withdrawal plan, change course and seek a further delay to Brexit, or crash out of the EU with no deal to cushion the shock.

Economists and business leaders warn that a no-deal Brexit would lead to huge disruptions in trade and travel, with tariffs and customs checks causing gridlock at British ports and possible shortages of goods.

A disorderly Brexit would hurt EU nations, as well as Britain, and all want to avoid it.

The British government insists it won't be obstructive, since it wants to keep close ties to the bloc. But pro-Brexit British politicians have said Britain should be disruptive.

Conservative lawmaker Mark Francois said that if the UK remained in the bloc, "then in return we will become a Trojan Horse within the EU".

May's future is uncertain, whatever the EU decides.

Heavy rains killed at least 10 people and left a trail of destruction in Rio de Janeiro on Tuesday, raising questions about the city’s preparedness to deal with recurring extreme weather.

Torrents of water gushed down streets, sweeping up cars and uprooting trees after rains that began around rush hour Monday evening.

Rains slowly weakened by Tuesday evening, but Mayor Marcelo Crivella said the city was still in “crisis” mode, the highest of three levels.

Schools were closed and people urged to avoid non-essential traffic until further notice.

City officials said 152 millimetres of rain fell in just four hours Monday night, more than the average for the whole month of April.

City officials said 6 inches of rain fell in just four hours Monday night, more than the average for the whole month of April.

The botanical garden neighbourhood, a tourist destination, was one of the most badly hit areas, receiving 9 inches in a 24-hour period.

Local television stations showed firefighters in that neighbourhood wading through knee-deep water pulling a small boatload of children evacuated from a school bus on a flooded street.

Sirens sounded in 20 flood-prone areas of the city, alerting people to make their way to pre-established safe spaces.

But no alarm was given in the Babilonia slum, which sits on a hill behind the iconic Sugarloaf mountain.

The fire department said two women there died in a mudslide, and local residents complained about the lack of warning.

The mayor, acknowledging the city’s lack of preparedness for the deluge, said sirens did not sound in Babilonia because the water had not reached the minimum threshold to activate the alarms.

He said officials would look into lowering this threshold in the future.

Hillside slums are particularly vulnerable to mudslides and city officials said more than 100 communities in Rio have been identified as having “high geological risks.”

Crivella said Rio has plans to improve safety, but complained of a lack of federal funding.

The mayor said a recent study carried out by the city identified about 200,000 road potholes and rainwater networks that needed fixing.

“We’re talking about hundreds of millions” of reals, the mayor said on Globo TV news, pressing President Jair Bolsonaro for more federal funding.

A storm with torrential downpours and strong winds just two months ago killed six people, prompting Rio residents to ask what the city is doing to protect them from routine weather events.

Rio’s fire department said that by Tuesday evening it had registered 10 deaths from the latest storm, including two adults and a child who were buried in a car by a mudslide.

According to news portal G1, the three victims were a little girl, her grandmother and their taxi driver.

Firefighters spent hours trying to reach the vehicle, going through mud, rubble and fallen trees.

An angry father convicted of killing his young son by slamming him against a bedhead is expected to learn his fate in a Queensland court.

Shane Purssell Akehurst, 37, threw toddler Corby Mitchell's tiny body against the wooden frame of a bed in March 2015.

The 21-month-old had been alone with his father at their isolated rural property in the Sunshine Coast hinterland while the rest of the family were shopping.

The impact on the boy's head was so forceful it caused whiplash and his eyes to bleed internally.

Despite the best efforts of paramedics and doctors, Corby was declared brain dead two days later and his life support system was switched off.

Akehurst, a FIFO worker and father of three, pleaded guilty to manslaughter in the Brisbane Supreme Court in January.

He also admitted a torture charge stemming from a series of assaults on his boy from November 2014.

An autopsy found Corby had 81 separate injuries.

They included crushed ribs that were weeks old, a missing fingernail and extensive facial injuries.

Akehurst told investigators he felt Corby's ribs "pop" after he gave him "a really good squeeze".

The boy's penis and scrotum were also bruised and the skin broken, which was likely to have been caused by forceful pinching, the court heard during sentencing submissions.

Akehurst told police he had anger issues that sometimes caused him to lose control.

He also admitted, on multiple occasions, punching Corby's head when the boy woke and called out to his mother during the night.

Defence lawyer Robert East said Akehurst's relationship with the child had suffered due to his heavy work roster, which kept him away from his family for three weeks in every four.

Akehurst is due to be sentenced in Brisbane Supreme Court today.

There are 150 electorates across Australia, with the winner of a majority of them taking government.

But while every vote counts as much as any other officially, the election is going to come down to a handful of key seats.

It's where we'll be seeing the Prime Minister and Opposition Leader kissing babies and donning hard-hats for the next few weeks.

FOLLOW LIVE: Scott Morrison announces May 18 Federal election

Here are the key seats to watch in this Federal Election.

Note: Actual margins from 2016 election can be found in brackets after seat name. Some seats have listed notional new margins based on the boundary changes in the federal redistribution.

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QUEENSLAND

Capricornia (0.63)

Large rural and regional seat based on Rockhampton in central Queensland. Michelle Landry (LNP) holds it on a very narrow margin. Third-generation coal miner Labor's Russell Robertson is seeking to win it, after Labor lost it in 2013. Jobs, health, roads, energy expected to be key issues. One Nation preferences could determine result.

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Herbert (0.02)

Labor's Cathy O'Toole holds the north Queensland seat based on Townsville by a mere 37 votes, after narrowly defeating the LNP's sitting member Ewen Jones in 2016. But former serviceman and 2018 Queensland Young Australian of the Year Phillip Thompson (LNP) will put up a fight, especially over the future of mining jobs, and could benefit from minor party preferences such as high school teacher Nanette Radeck (Katter's Australian Party). Defence, national security, jobs, infrastructure key issues.

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Longman (0.79)

Won by Labor's Susan Lamb in 2016 and retained in a July 2018 by-election (over her dual citizenship) with a 4.45 per cent margin. LNP has preselected local businessman Terry Young. Small business, jobs, horticulture, roads key issues. The success of the Greens and conservative minor parties will be crucial to who wins, but Labor should hold.

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Forde (0.63)

Logan-based industrial and small business seat south of Brisbane, it has been held by Bert van Manen (LNP) since 2010. He faces a tough fight with Labor candidate Des Hardman in a seat which has swung back and forth between the major parties since it was created in 1984.

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Flynn (1.04)

Huge central Queensland seat based on the port of Gladstone held by LNP's Ken O'Dowd. He has been sitting member since 2010. Coal, gas, grain, cattle are the key businesses. Labor's Zac Beers is a strong chance of winning. But Sharon Lohse(One Nation) preferences will be crucial. Minor parties got O'Dowd over the line in 2016.

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Dickson (1.6)

Home Affairs Minister Peter Dutton has held the seat since 2001, but the margin has narrowed after the 2016 election and subsequent redistribution. Mortgage belt seat covering Brisbane's northwestern suburbs, with some rural parts. Grass-roots campaigning by GetUp and others is putting pressure on Dutton, who was hit by a 5.1 per cent swing in 2016. Labor's Ali France is hopeful of doing well, but will require a strong showing from the Greens' Benedict Coyne to win.

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Dawson (3.34)

Nationals MP George Christensen has held this north Queensland seat since 2010. Labor has been targeting the seat, with candidate Belinda Hassan. Conservative minor party preferences should flow strongly to Christensen.

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Petrie (1.65)

Northern Brisbane seat, mainly residential with some light industrial and commercial activities. Held by the LNP's Luke Howarth since 2013, but is now vulnerable to Labor candidate Corinne Mulholland, who is campaigning strongly on health issues. Greens preferences could put Labor over the line.

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Bonner (3.39)

A Labor target seat based in Brisbane's industrial inner south. Held by LNP's Ross Vasta who has won and lost the seat in recent years. A double-figure showing by the Greens could help Labor's Jo Briskey.

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VICTORIA

Flinders (7.77)

Health Minister Greg Hunt will battle ex-Liberal Julia Banks, who is giving up her seat of Chisholm to run as an independent. A redistribution has chipped away Hunt's margin, but he's held it since 2001 and is a born and bred local. Green, Labor and minor party preferences could benefit Banks.

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Corangamite (3.13)

Liberal MP Sarah Henderson holds this redrawn seat, based on Geelong and the Great Ocean Road communities, with an estimated margin of 0.03 per cent (was 3.1 at the election). She won the seat in 2013, was re-elected in 2016 but could face pressure from Labor's Libby Coker.

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Macnamara (formerly Melbourne Ports) (1.38)

Labor's Michael Danby is retiring after more than 20 years in the seat, which has been redrawn to reduce the margin to an estimated 1.2 per cent. Labor's Josh Burns will face a battle with the Liberals' Kate Ashmor, a local lawyer, and the Greens' Steph Hodgins-May, who in 2016 came within 477 votes of taking the seat (which would have made her the first female Greens MP in the lower house).

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Dunkley (1.43)

The redistribution has made this south-east Melbourne seat held by Chris Crewther for the Liberals since 2016 into a marginal Labor seat. Labor's Peta Murphy will need to lift her primary vote from the 2016 result to win.

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La Trobe (1.46)

The Liberals' Jason Wood has been the on-again off-again member since 2004. The redistribution appears to have strengthened his hand but a 3.5 per cent margin still makes it a target seat for Labor, whose candidate is Simon Curtis. Labor has campaigned strongly on school funding in the outer metropolitan seat which has a mixed bag of industries from farming to construction and tourism.

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Chisholm (1.24)

Sitting MP Julia Banks is running in Flinders, having quit the Liberal Party over its attitude to women and other issues, to sit as an independent. Banks was the only Liberal to win a seat off Labor in the 2016 election. Before that Labor held Chisholm since 1998. Labor's candidate is Jenny Yang, who has been a local mayor. The Liberals are running Gladys Liu, a speech pathologist who has also advised Victorian Liberal premiers. The Liberals hold the seat with a notional margin of 2.9 per cent.

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Indi (4.83)

Independent Cathy McGowan is retiring from this regional Victorian seat, but her formidable campaign team is swinging behind health researcher Helen Haines. The Liberals have preselected engineer Steve Martin and the Nationals are running Mark Byatt, a key figure in tourism and development in the region. Hard to pick.

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NSW

Cowper (4.56)

Former independent MP Rob Oakeshott, who helped deliver Julia Gillard minority government in 2010, is taking another shot at returning to parliament in the wake of Nationals MP Luke Hartsuyker retiring. He faces the Nationals' Patrick Conaghan in the marginal NSW mid-north coast seat, and could benefit from Labor and Greens preferences.

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Gilmore (0.73)

The Liberals controversially preselected former Labor national president Warren Mundine for this NSW south coast seat being vacated by MP Ann Sudmalis. The man who was to be the Liberal candidate, Grant Schultz, is standing as an independent with the support of some disgruntled local party members. The Nationals are standing former NSW minister Katrina Hodgkinson. Given the 0.7 per cent margin, Labor's Fiona Phillips is hopeful of winning the seat amid the coalition chaos.

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Robertson (1.1)

The Liberals' Lucy Wicks has held this NSW central coast seat since 2013. But with it now sitting on a 1.1 per cent margin, Labor's Anne Charlton could draw on the preferences of Greens candidate Cath Connor and slip over the line.

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Lindsay (1.1)

Labor has chosen former NSW state minister Diane Beamer as its candidate following the scandal over sitting member for Lindsay Emma Husar's "unreasonable" treatment of her staff. As of April 4 it was unclear whether Husar will contest as an independent. Melissa McIntosh is contesting the 1.1 per cent margin seat for the Liberals, with Fiona Scott having lost the seat to Husar in 2016.

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Banks (1.4)

Immigration Minister David Coleman is defending the seat he has held since 2013, but Labor's Chris Gambian is in with a chance in this southern Sydney electorate. Banks, which is home to light manufacturing, commercial and service industries, was held continuously by Labor from its inauguration in 1949 to 2013.

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Page (2.3)

This largely rural and tourism based NSW north coast seat is held by the Nationals' Kevin Hogan by 2.3 per cent. Hogan sits on the crossbench in parliament, having become disgruntled with the coalition leadership revolving door. The seat, which is the fifth poorest in the nation, has swung between Nationals and Labor since its creation in 1984. Labor's Patrick Deegan, a social worker who hails from Casino, is a solid chance at regaining the seat.

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Eden-Monaro (2.9)

This southern NSW seat was once considered a bellwether (going to the party that wins government) but Labor's Mike Kelly brought that to an end in 2016. The 2019 race will be fascinating as the Liberals and Nationals are standing candidates, which will maximise the chances of a coalition win. Labor's best hope lies in a strong Greens preference flow. The coalition will be banking on a positive response to Snowy 2.0 supercharging the local economy. A margin of 2.9 per cent makes it a close-run thing.

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Reid (4.7)

Former minister and Malcolm Turnbull supporter, Craig Laundy, is retiring and will be replaced by child psychologist Fiona Martin. Labor has preselected business manager Sam Crosby, who grew up in Sydney's inner west. The seat had been consistently in Labor hands until the 2013 election, when Laundy became the seat's first Liberal member.

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Warringah (11.1)

Tony Abbott's beachside Sydney seat would not normally be in a list like this but he is facing a barrage of contestants including former Winter Olympian Zali Steggall. It will take a huge swing (in the vicinity of 12 per cent) to unseat the former prime minister. But stranger things have happened in elections.

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Wentworth (17.8)

Another seat that usually does not feature in such lists, but independent Kerryn Phelps will face a battle to retain the 1.2 per cent margin inner Sydney seat against former diplomat Dave Sharma. Phelps and Sharma faced off in a by-election to replace former prime minister Malcolm Turnbull. Phelps retains a high profile from her advocacy for asylum seekers and work with the Australian Medical Association.

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TASMANIA

Bass (6.1)

This north-eastern Tasmanian seat has swung wildly in recent elections being won by Labor's Ross Hart in 2016. The redistribution has made it slightly more difficult for Labor but it still has a 5.4 per cent margin. Both the Liberals and Nationals are running candidates which will ensure a strong conservative preference swap. A double-digit Greens primary vote is not out of the question. Unclear how it will pan out.

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WESTERN AUSTRALIA

Hasluck (2.1)

This Perth metropolitan seat has been held by federal minister Ken Wyatt since 2010. But his margin has been chipped away to 2.1 per cent. Labor candidate James Martin has a financial industry background and almost two decades in the Army Reserves. Speculation the 66-year-old incumbent was thinking about retiring won't help his cause.

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Stirling (6.1)

Liberal MP and minister Michael Keenan is retiring which should increase the chances of Labor picking up this Perth northern suburbs seat. Keenan has been the local MP since 2004. Labor candidate Melita Markey has been a long-time advocate for asbestos disease victims. The Liberal candidate, former soldier Vince Connelly, defeated four women for preselection despite Keenan's preference to be replaced by a female candidate.

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Swan (3.6)

Former Labor leader Kim Beazley's daughter Hannah is contesting this Perth inner southern suburbs seat, held by Liberal veteran Steve Irons since 2007. Name recognition may help Labor.

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Pearce (3.6)

Attorney-General Christian Porter has a reasonable chance of holding this northern Perth seat, which he first won in 2013, but Labor has made inroads at a state level as young families move into new suburbs. Labor's Kim Travers spent almost three decades in the police service and is a long-time mental health advocate.

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SOUTH AUSTRALIA

Boothby (3.5)

Nicolle Flint won the seat in 2016 after the retirement of Andrew Southcott and holds it with a notional margin of 2.8 per cent after the redistribution. Labor has been targeting Flint over her support for a leadership spill against Malcolm Turnbull. It has preselected local Nadia Clancy. The seat will be in play and Greens/independent preferences will play a role.

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Mayo (5)

First-term Centre Alliance MP Rebekha Sharkie retained the Adelaide Hills and SA coast seat in a by-election after being struck down in the citizenship scandal. She faces another challenge from Liberal blue-blood Georgina Downer. Sharkie should hold but the Liberals are keen to pick it up and will throw a lot of resources at it.

More than 200 Australians have drowned on public holidays in the past 15 years and people are twice as likely to die in waterways around the country on those days compared to every other day.

The worrying statistic released today by Royal Life Saving Australia comes ahead of the Easter weekend period, when five public holidays will fall within a week.

Justin Scarr, Royal Life Saving Australia’s CEO, said in a statement today that Australians need to be conscious of the risks of swimming on public holidays.

“With many Australian’s making the most of the extended holiday period, we’re urging everyone to take care around the water this Easter long weekend,” he said.

“Always remember that water conditions can change hourly and that the majority of these areas are not patrolled by lifeguards.”

The research also found that, among the 210 deaths over the past 15 years, alcohol has been a contributing factor that led to drownings, with men more also four-times as likely to die as women.

“There are a number of contributing factors… certainly the increased activity in or around our waterways,” Craig Roberts, Royal Life Saving Australia’s national manager of operations, told 9News.com.au.

“There are a range of people going inter-state or intra-state, going into waterways that they’re not particularly familiar with.

“Especially those males over the age of 18 - specifically 18 to 25-year-olds - on those public holidays are at a high risk of drowning.

“Males especially at that age group are more likely to take higher risks in and around our waterways, consume alcohol, participate in activities with friends where they overestimating their abilities and underestimating the risks associated with particular activities.”

The statistics also show that travellers who venture away from home to enjoy a public holiday long weekend are at least 2.5-times as likely to drown on those days than any other in the calendar.

Those figures come after five people drowned on the same day on Australia Day this year.

“It’s really important that you heed those safety messages, look out for each other, know you’re limits and make sure you have a fun time but have it safely,” Mr Roberts said.

Following reporting by nine.com.au, Australia’s two highest water safety bodies – Surf Lifesaving Australia and the Royal Lifesaving Society Australia – united last month in calling for action to turn around the country’s tragic drowning death toll.

In total, 114 people drowned around the country in the three months of summer – with 37 more deaths recorded this year than in 2017-18 in what could become the worst on record for water-related deaths.

In light of those numbers, Australia’s four major airlines are now working towards implementing on-board water safety videos on every flight in a bid to increase awareness and help save lives.

The Prime Minister PM made a pitch for re-election based on the economy and national security.

A former top Scotland Yard homicide detective believes British police could be sitting on "a real game changer" if Madeleine McCann's DNA is found in unsolved samples currently being sought by one of the world's leading DNA scientists.

Following an investigation by Nine.com.au, leading American forensic scientist Dr Mark Perlin last week formally offered to help London Metropolitan Police untangle 18 complex DNA samples, ruled "inconclusive” in 2007, which are potentially loaded with vital clues about Madeleine's disappearance.

Sixteen of the DNA samples of interest to Dr Perlin were taken from the McCann's holiday apartment, where Madeleine vanished, and the remaining two are from the boot compartment of a car hired by Maddie's parents, Kate and Gerry, several weeks after she disappeared.

In episode seven of Maddie, a podcast investigating Madeleine's mysterious disappearance, retired London Metropolitan Police detective Colin Sutton was asked what it could mean if Dr Perlin's analysis confirmed the presence of Madeleine's DNA in that rental car, a silver Renault Scenic.

"On that basis, that that car was hired by the McCanns three weeks after Madeleine disappeared, then it is a real game changer, isn't it? Because there is no way, according to information that we have, that she could have been in that car," said Sutton, who solved more than 30 murders, including catching English serial killer Levi Bellfield.

"The big question then is how can her DNA get into that car three weeks after she disappeared?"

Alternatively, Dr Perlin's analysis could conclusively rule out Madeleine as ever having been in the car, helping to narrow the focus of the investigation, as well as shed light on some of the questions around the other DNA samples.

Sutton added that the 16 "inconclusive" DNA samples lifted from the living room of the McCann's apartment 5A at the Ocean Club Resort could be of signficant value to investigators if Dr Perlin is able to establish whose DNA is present in that evidence.

In 2007 a British lab judged those 16 samples too complex to analyse. But Dr Perlin claims his advanced testing methods, used to identify victims of the September 11 terror attack, can successfully decipher that evidence.

"Where it would become interesting - and I understand this is the situation that you have in 5A - is where the material bearing the DNA is found in locations which would not in the ordinary course of events be subject to regular touching," Sutton said.

"So if you've got a situation where there is material found in cracks and crevices between tiles and skirting boards … that would probably indicate the possibility of, at least, some kind of DNA bearing material had been there and some attempts had been made to clean the material off.

“But the cleaning process isn't good enough or thorough enough to get into the cracks or crevices where access is difficult.

"That's the thing that's much more interesting from an investigator's point of view, because you start to ask the question how did that material get into that inaccessible location and what might it mean for what happened before and after?"

Many of the 16 DNA samples were lifted from skirting board and tiles lifted from the floor in areas behind a blue two-seat sofa. It is entirely possible an unknown intruder's DNA is present in those samples. If an abductor took Madeleine, Dr Perlin's DNA analysis could help identify someone still at large who was involved in her disappearance.

"Spatial mapping of who touched what or left their material at different locations ... can aid investigators in understanding or reconstructing the events that happened," Dr Perlin said.

"It can help an investigator understand who was where and what they may have done."

Dr Perlin said if Madeleine's DNA was found in the boot of the Renault Scenic, DNA transference could potentially explain those results.

"Secondary DNA transfer could occur [if] there was a suitcase in someone's apartment and DNA was left in some reasonably large quantity on that suitcase and then that suitcase was moved into the luggage compartment of the car," he said.

"There's a whole science to DNA transfer. It's not that common. It can happen."

Last week Nine.com.au revealed Dr Perlin, the chief scientist at Pittsburgh laboratory Cybergenetics, had formally offered his services to the head of Operation Grange, Scotland Yard's investigation in Madeleine's disappearance.

Operation Grange is on the brink of receiving further funding from the UK Home Office. Since launching in 2011, Operation Grange has cost UK taxpayers $21 million.

Nine.com.au understands the Home Office is considering a request from Scotland Yard to fund Operation Grange through to March 2020.

Mr and Mrs McCann, both doctors from Rothley, Leicestershire, have strenuously denied they were involved in the disappearance of their daughter. Nine.com.au does not suggest any involvement on their part. 

The McCanns had left their children alone while they ate dinner at a nearby restaurant with a group of friends, known as the Tapas 7.

They believed an intruder struck while they were out, snatching Madeleine from a bedroom where she was sleeping alongside her younger brother and sister.

Aged three when she vanished, Madeleine would turn 16 in 2019.

LISTEN TO LATEST EPISODES OF MADDIE NOW

Maps, graphics, stories and all episodes of Maddie here: nine.com.au/maddie

Imagine trying to take a photo of an orange that's on the moon with your smartphone. It seems impossible.

That's what it was like for scientists trying to capture an image of a black hole in space. Despite the tall order, an international team of more than 200 researchers unveiled the first-ever image of a black hole on Wednesday.

The effort wouldn't have been possible without Katie Bouman, who developed a crucial algorithm that helped devise imaging methods.

Three years ago, Bouman led the creation of an algorithm that eventually helped capture this first-of-its-kind image: a supermassive black hole and its shadow at the centre of a galaxy known as M87. She was then a graduate student in computer science and artificial intelligence at the Massachusetts Institute of Technology.

Black holes are extremely far away and compact, so taking a photo of one is no easy task. In addition, black holes by definition are supposed to be invisible -- although they can give off a shadow when they interact with the material around them.

A global network of telescopes known as the Event Horizon Telescope project collected millions of gigabytes of data about M87 using a technique known as interferometry. However, there were still large gaps in the data that needed to be filled in.

Her algorithm, and many others, helped fill in the gaps

That's where Bouman's algorithm -- along with several others -- came in. Using imaging algorithms like Bouman's, researchers created three scripted code pipelines to piece together the picture.

They took the "sparse and noisy data" that the telescopes spit out and tried to make an image. For the past few years, Bouman directed the verification of images and selection of imaging parameters.

"We developed ways to generate synthetic data and used different algorithms and tested blindly to see if we can recover an image," she told CNN.

"We didn't want to just develop one algorithm. We wanted to develop many different algorithms that all have different assumptions built into them. If all of them recover the same general structure, then that builds your confidence."

The result? A groundbreaking image of a lopsided, ring-like structure that Albert Einstein predicted more than a century ago in his theory of general relativity. In fact, the researchers had generated several photos and they all looked the same. The image of the black hole presented on Wednesday was not from any one method, but all the images from different algorithms that were blurred together.

"No matter what we did, you would have to bend over backwards crazy to get something that wasn't this ring," Bouman said.

Bouman was a crucial member of the imaging team

"(Bouman) was a major part of one of the imaging subteams," said Vincent Fish, a research scientist at MIT's Haystack Observatory.

"One of the insights Katie brought to our imaging group is that there are natural images," Fish said. "Just think about the photos you take with your camera phone -- they have certain properties. ... If you know what one pixel is, you have a good guess as to what the pixel is next to it."

For example, there are areas that are smoother and areas that have sharp boundaries. Astronomical images share these properties, and you can mathematically encode these properties, Fish said.

Junior members like Bouman made significant contributions to the project, he added. Of course, senior scientists worked on the project, but the imaging portion was mostly led by junior researchers, such as graduate students and post docs.

"No one of us could've done it alone," Bouman said. "It came together because of lots of different people from many backgrounds."

Bouman starts teaching as an assistant professor at California Institute of Technology in the fall.