The find comes from the largest sample of supernovae ever detected by a single telescope
Dark energy – the mysterious substance that’s apparently driving our Universe apart – could vary with time, according to the latest results from the Dark Energy Survey (DES).
In 1998, two teams of astronomers measured the expansion of the Universe by looking at Type Ia supernovae. These occur when a white dwarf steals stellar material from a nearby companion star until it reaches a critical mass and explodes in a supernova. Because they are always the same mass when they explode, Type Ia supernovae all have the same intrinsic brightness. By comparing this to their apparent brightness, astronomers arrive at an accurate measure of their distance.
The 1998 study also measured their redshift and was able to gauge how fast the supernovae’s home galaxies were moving away from us. Together, this allowed the teams to measure how fast the Universe was expanding. However, rather than finding the expansion was slowing as expected, the team found it was actually accelerating. To explain this fact, cosmologists hypothesised ‘dark energy’, which is driving the fabric of the Universe apart.
Beginning in 2013, the DES sought to create the most accurate measurements of our Universe’s expansion. The initiative spent six years mapping one-eighth of the sky, observing two million distant galaxies. This latest study scour
