Probing Dark Energy

Dark energy illustration. Credit: Visualization by Frank Summers, Space Telescope Science Institute. Simulation by Martin White, UC Berkeley and Lars Hernquist, Harvard University





Could one of the biggest puzzles in astrophysics be solved by reworking Albert Einstein’s theory of gravity? Not yet, according to a new study co-authored by NASA scientists.

The universe is expanding at an accelerating rate, and physicists don’t know why. This phenomenon seems to contradict everything scientists understand about gravity’s effect on the cosmos: It’s as if you threw an apple in the air and instead of coming back down, it continued upward, faster and faster. The cause of the cosmic acceleration, dubbed dark energy, remains a mystery.

A new study marks the latest effort to determine whether this is all simply a misunderstanding: that expectations for how gravity works at the scale of the entire universe are flawed or incomplete. This potential misunderstanding might help researchers explain dark energy. However, the study – one of the most precise tests yet of Albert Einstein’s theory of gravity at cosmic scales – finds that the current understanding still appears to be correct. The study was from the international Dark Energy Survey, using the Victor M. Blanco 4-meter Telescope in Chile.


The results, authored by a group of scientists that includes some from NASA’s Jet Propulsion Laboratory (JPL), were presented Wednesday, August 24, at the International Conference on Particle Physics and Cosmology (COSMO’22) in Rio de Janeiro. 

The work helps set the stage for two upcoming space telescopes that will probe our understanding of gravity with even higher precision than the new study and perhaps finally solve the mystery.  READ MORE...