A new analysis of more than 1,500 supernovae has established new accuracy in measurements of the dark matter and dark energy that permeate our universe.
According to research, about two-thirds of the universe (66.2%) is made up of dark energy and the remaining third (33.8%) is made up of matter. Almost all matter is so-called “dark,” which means we can’t actually see it; We know it exists only because we can measure its gravitational effects. The normal matter that we can touch and see makes up less than 5% of the universe. The team’s analysis, called Pantheon+, is Publish Today in The Astrophysical Journal.
The results have implications for astrophysicists’ measurements of the Hubble constant, a number that describes the expansion rate of the universe. This number has always been a mystery, because it varies greatly depending on whether it is measured locally or on a cosmic scale.
Dillon Pruitt, an astrophysicist and member of theCenter. Astrophysics | Harvard and Smithsonian and lead author of the article. “In principle, that’s great, however, the same data set also takes Hubble pressure to a new level.” More on that tension in a moment.
Matter is everything in the universe. dark matter It is the uncalculated mass in the universe that we cannot directly observe but is proven by gravitational effects. Includes dark matter filters Axions, WIMPs, and other subatomic particles ; It could also be a mixture of these supposed audiences, or something else entirely. Dark energy (so named because we don’t know exactly what it’s made of) is what drives the accelerating expansion of the universe.
Pantheon+ analyzed the expansion rate of the universe using Type Ia supernovae, the violent outbursts that signal the end of a star’s life. Astrophysicists can use the apparent brightness and redshift of these supernovae to calculate the speed at which the universe has expanded during different periods of its existence.
Pantheon+ is based on Pantheon itself, an analysis of about 1,000 supernovae. The new work is twice as accurate as the original Pantheon data. The team also combined their results from Pantheon+ with measurements of the universe’s structure and its oldest light, the cosmic microwave background.
Type Ia . supernova They are some of the brightest events in the universe and could overwhelm entire galaxies. Some of these supernovae have occurred in a very distant universe, which means they are more redshifted. When the universe expands, it stretches the light that passes through it; When the light reaches the ground, it appears redder (with a longer wavelength) than when it was emitted.
The team combined the Pantheon+ data with data from SH0ES, a collaboration that uses data from supernovae to calculate the Hubble’s local constant, or how fast the universe is expanding. Taken together, the data yielded a constant of 45.61 miles (73.4 km) per second per megaparsec. This still differs from the Hubble constant that was calculated using the cosmic microwave background, the oldest light in the universe. This discrepancy between local and remote measurements is what Brutt referred to as “Hubble stress.
New discovery raises certainty about stress to a minimum 5 sigmaAnd the Which means there’s only a one-in-a-million chance that the long-running discrepancy in the Hubble constant measurements is just a coincidence.
The Pantheon+ data covers what Brout describes as a “late” universe, meaning the supernovae included in the analysis date from approximately 10 billion years ago to the present. Some current theories about bridging the gap between the two Hubble numbers include examining the oldest physics in the universe, using light sources such as Web Space Telescope Views .
Fortunately, Prout said, there are instruments on the horizon that “will lead to a tidal wave of supernovae, which will dwarf the current + pantheon sample.” Chief among them is the Vera Rubin LSST camera ( Who visited Gizmodo last October It will be completed in early 2023) and NASA’s Nancy Grace Roman Space Telescope, which is expected to launch in mid-2020.
To measure the Hubble constant, it would be useful to capture data on a nearby supernova, which means waiting for a nearby star to die. If that happens, new technology like the Webb telescope can quickly generate an image in infrared and near infrared wavelengths. These measurements will help scientists understand how dust surrounding supernovae can cause errors in astrophysical calculations, thus improving the accuracy of Hubble’s constant measurements..
Research like this should bring us closer to finally solving the mystery of dark energy and dark matter, although we still don’t understand much at the moment..
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