Measuring the distance to far-off objects like galaxies and supernovae is essential for understanding the universe, especially its early stages.
However, this task is quite challenging. We can only directly measure the distances to nearby objects like the sun, planets, and some stars.
For more distant objects, astronomers use indirect methods, and one of the most reliable involves Type Ia supernovae.
This is where the NASA/ESA Hubble Space Telescope excels.
In 2022, the galaxy NGC 3810 hosted a Type Ia supernova. In early 2023, Hubble focused on this galaxy and several others to study recent Type Ia supernovae. These supernovae occur when a white dwarf star explodes, and their peak brightness is very consistent.
This consistency allows astronomers to measure distances because they know how bright a Type Ia supernova should be. By observing how dim the supernova appears, they can calculate its distance.
However, intergalactic dust complicates this method. Dust can block some of the supernova’s light, making it appear dimmer and skewing distance measurements. Hubble offers a clever way to account for this dust.
Astronomers use Hubble to capture images of the same supernovae in both ultraviolet and infrared light. Ultraviolet light is almost completely blocked by dust, while infrared light passes through it almost unaffected.
By comparing the light at these two wavelengths, astronomers can determine how much dust is between Hubble and the supernova. This helps them accurately measure the supernova’s brightness and calculate its distance.
Hubble’s ability to observe in both ultraviolet and infrared light with great detail makes it the perfect tool for these observations. Some of the data used to create the beautiful image of NGC 3810 focused on its 2022 supernova.
There are many ways to measure cosmic distances, but Type Ia supernovae are particularly useful and accurate because they are so bright. Astronomers also use other methods to cross-check their measurements or to measure distances at different scales.
One alternative method for measuring distances to galaxies is to compare their rotation speed to their brightness. Using this method, astronomers have determined that NGC 3810 is about 50 million light-years from Earth.
In summary, Hubble’s unique capabilities allow astronomers to measure the distances to far-off supernovae accurately, helping us better understand the vast universe.
