- Muslim women break taboos navigating east London's waterways
- Nepal dam-building spree powers electric vehicle boom
- More than 60 dead from storm Helene as rescue, cleanup efforts grow
- Dozens missing, 9 dead in migrant boat wreck off Spanish Canaries
- Death toll from Hurricane John hits eight in Mexico
- Storm Helene's toll rises as rescue and cleanup efforts gain pace
- SpaceX launches mission to return stranded astronauts
- Storm Helene kills 44, threatens more 'catastrophic' flooding as cleanup begins
- SpaceX set to launch mission to return stranded astronauts
- Storm Helene kills 44, threatens more 'catastrophic' flooding
- Boeing strike grinds on as latest talks fail to reach agreement
- Iran 'news' sites, hackers target Trump ahead of US election
- US ports brace for potential dockworkers strike
- Japan's speedy, spotless Shinkansen bullet trains turn 60
- US hurricane deaths rise to 44, fears of more 'catastrophic' flooding
- Global stocks mostly rise, cheering Beijing stimulus
- Europe en route for Moon with new simulator, says astronaut Pesquet
- Fireworks forecast if comet survives risky Sun flypast
- Argentina judge orders dictionary to delete pejorative definition of 'Jewish'
- Global stocks rise on rate hopes, Beijing stimulus
- S.African woman turns 118, among the oldest in the world
- UK clears $4 bn AI partnership between Amazon, Anthropic
- Barca fans barred from Champions League away game over racist banner
- Chinese stocks extend surge, Europe higher on Beijing stimulus
- Pope says Church must 'seek forgiveness' for child sexual abuse
- China caps week of 'bazooka' stimulus for ailing economy with rate cut
- Cuts, cash, credit: China bids to jumpstart flagging economy
- France's debt weighs heavier ahead of budget debate
- Iran treads carefully, backing Hezbollah while avoiding war
- Return to sender: waste stranded at sea stirs toxic dispute
- 'Broken' news industry faces uncertain future
- On remote Greek island, migratory birds offer climate clues
- Taken from mother by nuns, victim seeks answers as pope visits Belgium
- China cuts amount banks hold in reserve to boost lending
- Hong Kong, Shanghai extend surge as China optimism boosts markets
- Vietnam president reiterates support for Cuba during official visit
- Drought reduces Amazon River in Colombia by as much as 90%: report
- Stay or go? Pacific Islanders face climate's grim choice
- Florida bracing for 'unsurvivable' Hurricane Helene
- Poverty rises to over 52 percent in Milei's Argentina
- Chloe's see-through look may not be for Kamala Harris
- Champagne houses abuzz over English sparkling wine
- Macron, Trudeau pledge to work for 'decarbonized' economies
- Hurricanes, storms, typhoons... Is September wetter than usual?
- China stimulus, tech optimism boost stock markets
- 'Unsurvivable' Hurricane Helene races towards Florida
- Macron meets Trudeau in Canada as both face political setbacks
- South Korea surges in UN innovation index
- Chloe's see-through look may not be for Kamala
- Floods threaten Niger's historic 'gateway to the desert'
Milky Way's fate? Astronomers reveal what ignites quasars
Astronomers said Wednesday that for the first time they have confirmed what ignites quasars, the brightest and most powerful objects in the universe, which put galaxies in their "death throes".
These celestial behemoths form when two galaxies smash into each other, the astronomers said, warning that this could be the Milky Way's fate in a few billion years.
Quasars are one of the most extreme objects in the universe, some shining with the brightness of a trillion stars despite being packed into the space of our Solar System.
They sit in the heart of galaxies, powered by supermassive black holes, requiring a huge amount of gas to be so staggeringly bright.
But exactly what creates quasars has been a matter of debate since their discovery in the 1950s.
In a new study, an international team of researchers said they have "clear evidence" that quasars are triggered by two galaxies colliding, which releases the vast amounts of energy needed.
Clive Tadhunter, an astrophysicist at the University of Sheffield in the UK and one of the study's authors, told AFP that this could be the fate of the Milky Way one day.
The nearby Andromeda Galaxy is "coming directly towards us at about 200 kilometres (125 miles) a second," he said.
It will collide with the Milky War in roughly five billion years, and "we could get a quasar" as a result, he said.
Quasars push out all the gas from a galaxy, preventing any new stars from forming, he added.
- 'Beacons to the distant universe' -
The researchers compared observations of 48 galaxies with quasars at their centre to 100 without them.
Galaxies hosting quasars were three times as likely to have had collisions with other galaxies, the study said.
While the theory that such collisions ignited quasars has been around for decades, it was difficult to prove.
Tadhunter said this was because observations had often been carried out with telescopes that were optimised to look at objects in the centre of galaxies, but were less effective at spotting the distorted features at their edges that indicate past collisions.
For example, these diffuse structures "get washed out" when observed by the Hubble Space Telescope, he said.
So the team used land-based observatories, such as the Isaac Newton Telescope on the Spanish island of La Palma.
The new study, published in the Monthly Notices of the Royal Astronomical Society, also reviewed previous research to show how it may have missed the tell-tale signs of collisions.
Tadhunter said that quasars "act like beacons to the distant universe" because of their incredible brightness.
The James Webb Space Telescope, which has a much bigger aperture than Hubble, could help reveal more about quasars in this distant universe, when the universe was in its infancy, he said.
M.Anderson--CPN