Supernovae as Cosmic Rulers
Scientists recently used analysis of over two decades' worth of supernova explosions to create the most precise measurements yet of dark energy and dark matter. These mysterious substances are thought to comprise 95% of the universe's content, but we can't directly observe them.
Illuminating the Dark Universe
Type Ia supernovae, the explosions of a specific kind of star, act like cosmic rulers. By studying the brightness and redshift (a measure of how stretched out light is) of these supernovae at various distances, astronomers can map the expansion history of the universe. This expansion, surprisingly, is accelerating, which is attributed to dark energy.
Pantheon+
The new analysis, called Pantheon+, incorporates data from multiple telescopes and refines calculations to provide the most accurate picture to date. It confirms that:
- Roughly two-thirds of the universe is dark energy.
- Dark matter makes up most of the remaining third.
- The universe's expansion has been accelerating for billions of years.
A Crossroads in Cosmology
Pantheon+ strengthens current cosmological models but also highlights areas for further exploration. It raises new questions about:
- The exact nature of dark energy and how it behaves.
- The properties and composition of dark matter.
By continuing to study supernovae and other cosmic phenomena, scientists hope to unlock the secrets of dark energy and dark matter and achieve a deeper understanding of our universe.