A filament filled with galaxies moving in helical motion. Image: AIP/ A Khalatyan/ J Fohlmeister
ABSTRACT breaks down mind-bending scientific research, future tech, new discoveries, and major breakthroughs.
Advertisement
Advertisement
Wang and his colleagues set out to investigate this problem by meticulously examining hundreds of thousands of galaxies within a few billion light years of Earth captured by the Sloan Digital Sky survey based in New Mexico.To probe angular motion in filaments, the team adopted a technique that has long been used to measure the rotations of galaxies. Scientists aiming to clock galactic spins make use of the Doppler effect, which manifests as a change in the frequency of waves that depends on where an observer is located in relation to those waves. The most famous example of this effect is the change in the pitch of a siren you hear as an ambulance drives by you; when the ambulance is approaching you, the sound waves are compressed into higher frequencies compared to the lower frequencies you hear when it passes you.Because the Doppler effect also occurs in light, radiant objects in space produce light waves that become compressed, or “blueshifted,” into a blue color when they are moving toward Earth and “redshifted” into a lower-frequency red color when they are moving away from our perspective. Generally speaking, the more blueshifted or redshifted an object appears to us, the faster it is moving toward or away from Earth.To apply this effect to the cosmic web, Wang’s team identified giant filament structures in the Sloane survey. The researchers then divided the dozens of galaxies within the threads into two regions placed on either side of the structure, and measured the redshifts of objects in those two regions.“There's some order in this chaotic universe.”
Advertisement
Advertisement