New Way to Measure Dark Energy

Researchers have discovered a method to potentially detect and measure dark energy by examining the motion between the Milky Way and Andromeda galaxies. This technique, still in its early stages, can estimate the upper value of the cosmological constant, a simple model of dark energy, which is five times higher than values determined from the early universe.




Researchers from the University of Cambridge have discovered a new way to measure dark energy – the mysterious force that makes up more than two-thirds of the universe and is responsible for its accelerating expansion – in our own cosmic backyard.

The researchers found that it may be possible to detect and measure dark energy by studying Andromeda, our galactic next-door neighbor that is on a slow-motion collision course with the Milky Way.


Since it was first identified in the late 1990s, scientists have used very distant galaxies to study dark energy but have yet to directly detect it. 

However, the Cambridge researchers found that by studying how Andromeda and the Milky Way are moving toward each other given their collective mass, they could place an upper limit on the value of the cosmological constant, which is the simplest model of dark energy. 

The upper limit they found is five times higher than the value of the cosmological constant that can be detected from the early universe.

Although the technique is still early in its development, the researchers say that it could be possible to detect dark energy by studying our own cosmic neighborhood. The results are reported in The Astrophysical Journal Letters.

Everything we can see in our world and in the skies – from tiny insects to massive galaxies – makes up just five percent of the observable universe. 

The rest is dark: scientists believe that about 27% of the universe is made of dark matter, which holds objects together, while 68% is dark energy, which pushes objects apart.  READ MORE...