Astro Brief: Expansion of the Universe

By Dr. Mike Reed

Published April 11, 2024 at 9:45 AM CDT

This image of NGC 5468, a galaxy located about 130 million light-years from Earth, combines data from the Hubble and James Webb space telescopes. This is the most distant galaxy in which Hubble has identified Cepheid variable stars. These are important milepost markers for measuring the expansion rate of the Universe. The distance calculated from Cepheids has been cross-correlated with a Type Ia supernova in the galaxy. Type Ia supernovae are so bright they are used to measure cosmic distances far beyond the range of the Cepheids, extending measurements of the Universe’s expansion rate deeper into space. [Image description: A face-on spiral galaxy with four spiral arms that curve outward in a counterclockwise direction. The spiral arms are filled with young, blue stars and peppered with purplish star-forming regions that appear as small blobs. The middle of the galaxy is much brighter and more yellowish, and has a distinct narrow linear bar angled from 11 o’clock to 5 o’clock. Dozens of red background galaxies are scattered across the image. The background of space is black.]

How do we measure our universe?

After the Big Bang, our universe began to expand at the speed of light. To determine this, scientists needed to find a way to measure our universe's rate of expansion. Research continues today as Dr. Adam Riess of Johns Hopkins University released a recent paper analyzing data from the James Webb Space Telescope on distant cepheid stars.

Join us this week as Mike discusses important and recent discoveries about our universe's expansion.

Astro Brief is a collaboration between KSMU, the Missouri Space Grant, and MSU's Department of Physics, Astronomy and Materials Science. Hosted by Dr. Mike Reed, Astro Brief focuses on astronomical events, the field of astronomy, and astronomy-related guests. It airs Thursdays at 9:45 am on KSMU.