7/26/2023 0 Comments Universe sandbox 2 dark matter![]() ![]() The further that light has traveled, the longer ago the light was originally emitted. The greater the redshift of an object, the further away it is from Earth. “You wouldn’t have any information about the distance without the redshift,” says Dragan Huterer, a professor of physics at the University of Michigan. ![]() The amount the spectrum moves is known as its redshift, which acts as a measure of distance from Earth. However, the pattern of the spectrum remains the same compared to similar stars or galaxies closer to Earth. This shifts an object’s entire emission spectrum toward the “redder” end of light’s range. During the recent Snowmass high-energy physics community planning process, scientists discussed powerful new spectroscopic instruments that could increase our reach into the stars.īecause the universe is expanding, the wavelengths of light emitted by a star or galaxy get stretched as they travel toward Earth. It’s also crucial for determining the distance of an object from Earth.įor more than two decades, cosmologists have been harnessing spectroscopy to investigate questions related to dark matter and dark energy. The obtained spectrum can then be used to figure out the composition and temperature of an object. Instead of taking normal images, the diffraction grating breaks up the light emitted by the target into its constituent colors. To collect the emission spectrum of an object in space, such as a star or galaxy, astrophysicists hook up a prism-like tool called a diffraction grating to a telescope. ![]() In spectroscopy, an emission spectrum describes what wavelengths, or colors, an object emits. Only a small sliver of this range makes up the familiar rainbow of visible light. Light’s full range spans from gamma rays at one end, which are “bluer” and have shorter wavelengths, to radio waves at the other, which are “redder” and have larger wavelengths. Unfortunately, this isn’t the dazzling show you might imagine, as much of this light is invisible to the human eye. Spectroscopy relies on the fact that all matter emits light, and different materials emit different arrays of light depending on their composition, temperature and motion. “It’s one of the key tools we have available to unveil mysteries about the physics of dark energy, dark matter and inflation because it allows us to build a 3D map.” “The spectroscopic information adds depth,” says Marcelle Soares-Santos, an assistant professor of physics at the University of Michigan who uses spectroscopy data in her work investigating the expansion of the universe. But these pictures are two-dimensional, and astrophysicists need a different tool to measure how far away objects are from Earth in our ever-expanding universe. Telescope images can tell us a whole lot about celestial objects: where they are located in the sky, how bright they are, how big they are and their shapes, among other attributes. ![]()
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