— NASA's Hubble confirms that galaxies are the ultimate recyclers — New observations by NASA's Hubble Space Telescope are expanding astronomers' understanding of the ways in which galaxies continuously recycle immense volumes of hydrogen gas and heavy…
— Frozen comet had a watery past, University of Arizona scientists find — For the first time, scientists have found convincing evidence for the presence of liquid water in a comet, shattering the current paradigm that comets never get warm enough to melt…
— Sugar-grain sized meteorites rocked the climates of early Earth and Mars — Bombardments of 'micro-meteorites' on Earth and Mars four billion years ago may have caused the planets' climates to cool dramatically, hampering their ability to support life, according…
— Astrophysicist: White dwarfs could be fertile ground for other Earths — Planet hunters have found hundreds of planets outside the solar system in the last decade, though it is unclear whether even one might be habitable. But it could be that the best place…
— Integral spots matter a millisecond from doom — ESA's Integral gamma-ray observatory has spotted extremely hot matter just a millisecond before it plunges into the oblivion of a black hole. But is it really doomed? These unique observations…
— MESSENGER spacecraft to swing into orbit around Mercury — At 8:45 p.m. EDT on March 17, the MESSENGER spacecraft will execute a 15-minute manoeuvre that will place it into orbit around Mercury, making it the first craft ever to do so, and…
— Baby stars born to 'napping' parents — Cardiff University astronomers believe that a young star's long 'napping' could trigger the formation of a second generation of smaller stars and planets orbiting around it…
— Oldest objects in solar system indicate a turbulent beginning — Scientists have found that calcium, aluminium-rich inclusions (CAIs), some of the oldest objects in the solar system, formed far away from our sun and then later fell back into the…
— Oxygen isotope analysis tells of the wandering life of a dust grain 4.5 billion years ago — Scientists have performed a micro-probe analysis of the core and outer layers of a pea-sized piece of a meteorite some 4.57 billion years old to reconstruct the history of its formation,…
Two supernovae at the edge of the Universe
Cosmologists from the University of California - Irvine have found two supernovae farther away than any previously detected by using a new technique that could help find other dying stars at the edge of the Universe. The discovery is published in the most recent issue (9 July) of the journal Nature. The supernovae occurred 11 billion years ago. The next-farthest large supernova known occurred about 6 billion years ago.
A supernova occurs when a massive star (more than eight times the mass of the sun) dies in a powerful, bright explosion. Cooke studies larger stars (50 to 100 times the mass of the sun) that blow part of their mass into their surroundings before they die. When they finally explode, the nearby matter glows brightly for years.
'When stars explode, they spew matter into space. Eventually, gravity collapses the matter into a new star, which could have planets such as Earth around it,' said Jeff Cooke, McCue Postdoctoral Fellow in physics and astronomy.
Typically, cosmologists find supernovae by comparing pictures taken at different times of the same swath of sky and looking for changes. Any new light could indicate a supernova. Cooke built upon this idea. He blended pictures taken over the course of a year, then compared them with image compilations from other years.
'If you stack all of those images into one big pile, then you can reach deeper and see fainter objects,' Cooke said. 'It's like in photography when you open the shutter for a long time. You'll collect more light with a longer exposure.'
Doing this with images from the Canada-France-Hawaii Telescope in Hawaii, Cooke found four objects that appeared to be supernovae. He used a Keck telescope to look more closely at the spectrum of light each object emitted and confirmed they were indeed supernovae.
'The Universe is about 13.7 billion years old, so really we are seeing some of the first stars ever formed,' Cooke said.
This method has the potential to allow astronomers to study some of the very first supernovae and will advance the understanding of how galaxies form, how they change over time and how Earth came to be.
Or subscribe for our Newsletter, a free e-mail publication. It is published practically every day.
Fifty years after Sputnik
The icy climate of Titan mimics our tropics
Star cluster bursts into life in new Hubble image
Dawn mission to asteroid belt launched