NASA telescope discovers exploding stars ‘almost everywhere’

NASA’s James Webb Space Telescope has revealed an unprecedented collection of ancient supernovae.

Astronomers report that they have found 10 times more of these stellar explosions than were previously known to have existed in the early universe. Some of these 80 newly discovered supernovae exploded when the universe was only about 2 billion years old — today’s universe is about 13.8 billion years old — making them some of the oldest ever found.

“Webb is a supernova discovery machine,” Christa DeCoursey, a third-year student at Steward Observatory and the University of Arizona in Tucson, said in a NASA statement. “The sheer number of detections plus the large distances to these supernovae are the two most interesting results of our survey.”

Supernovae are huge explosions that occur when a star dies. They emit huge amounts of energy when the star’s core collapses in on itself when it runs out of fuel. These supernovae often leave behind black holes or neutron stars when the parent star is large, or white dwarfs for smaller stars.

Astronomers from the JWST Advanced Deep Extragalactic Survey (JADES) found these new supernovae in a tiny patch of sky, the equivalent of the thickness of a grain of rice held at arm’s length.

“Because Webb is so sensitive, it finds supernovae and other transients almost everywhere it points,” JADES team member Eiichi Egami, a research professor at the University of Arizona in Tucson, said in a statement. “This is a major first step towards a more extensive survey of supernovae with Webb.”

Astronomers detected these ancient supernovae thanks to a phenomenon known as cosmological redshift, which is where light from distant galaxies appears redder than it should be. This occurs because the universe is expanding, causing the space between galaxies to expand. Light is stretched by being shifted towards the red end of the spectrum – because red light has a longer wavelength than blue light – which means that when astronomers observe light from distant galaxies, they see this red shift, which tells them that these galaxies are moving away from us due to the expansion of the universe.

“This is really our first sample of what the high-redshift universe looks like for transient science,” Justin Pierel, a NASA Einstein Fellow at the Space Telescope Science Institute (STScI) in Baltimore, Maryland, said in a statement. “We’re trying to find out if distant supernovae are fundamentally different from what we see in the nearby universe, or if they’re very similar.”

The discovery of these 80 new JWST supernovae was revealed by astronomers from the JADES program at a press conference at the 244th meeting of the American Astronomical Society in Madison, Wisconsin. Before the launch of JWST, only a few supernovae had been discovered with a redshift value consistent with having existed when the universe was younger than about 3.3 billion years.

One of the newly discovered supernovae exploded when the universe was only 1.8 billion years old, making it the most distant, and therefore the oldest, ever found.

Astronomers are particularly interested in the types of supernovae known as Type Ia supernovae, which have a predictable intense brightness. This means they can be used to calculate the expansion rate of the universe using redshift. In this recent find, they discovered at least one Type Ia supernova from when the universe was 2.3 billion years old, making it the oldest known Type Ia supernova. This can help scientists study whether the brightness of these supernovae changes with redshift, which would affect their ability to be reliable predictors of the universe’s expansion rate.

The findings may also help astronomers study how supernovae in the early universe differed from those today, and how this may have affected the formation of early stars and planets.

“Essentially, we’re opening a new window into the transient universe,” STScI member Matthew Siebert, lead spectroscopic analysis of JADES supernovae, said in a statement. “Historically, whenever we’ve done that, we’ve found extremely exciting things — things we didn’t expect.”

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