The Hubble Space Telescope aids in cosmic distance measurement by observing Type Ia supernovae, like those in NGC 3810, using their consistent brightness to gauge distances adjusted for intergalactic dust effects. Credit: ESA/Hubble & NASA, D. Sand, R. J. Foley
Measuring cosmic distances is essential in astrophysics, with the planets, and some nearby stars can we measure their distances directly. Beyond that, various indirect methods need to be used; one of the most important is by examining Type Ia supernovae, and this is where the 
This image depicts the spiral galaxy NGC 3810, which in 2023 was included in a Hubble programme to improve the accuracy of distance measurements made using Type Ia supernovae. This was only possible because a white dwarf in NGC 3810 had just gone supernova, and Hubble captured this image before the supernova faded from view.
Supernovae are named for their year of discovery, followed by an incrementing tag of letters — a, b, and so on. Nowadays, with automated surveys, thousands of supernovae are discovered every year, and so this one received the name SN 2022zut, as the eighteen thousand, one hundred and forty-second found in 2022!
Credit: ESA/Hubble & NASA, D. Sand, R. J. Foley
Hubble can observe both these wavelengths of light in great detail with the same instrument. That makes it the perfect tool for this experiment, and indeed, some of the data used to make this beautiful image of NGC 3810 were focused on its 2022 supernova. You can see it as a point of light just below the galactic nucleus, or in the annotated image above.
There are many ways to measure cosmic distances; because Type Ia supernovae are so bright, they are one of the most useful and accurate tools, when they’re spotted. Many other methods must be used as well, either as an independent check against other distance measurements or to measure at much closer or farther distances. One such method that also works for galaxies is comparing their rotation speed to their brightness; based on that method, NGC 3810 is found to be 50 million light-years from Earth.
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