Archive · 14 Nov 2025
DESI's Latest Measurements Suggest Dark Energy May Be Changing Over Time
Imagine the universe is like a balloon that's getting bigger.
For a long time, scientists thought there was a mysterious force called dark energy making it expand faster and faster at a steady rate.
But new measurements from a super-powered telescope called DESI suggest this force might not be steady.
It could be changing, like a dimmer switch that's slowly turning down.
If dark energy is indeed changing, it means our universe might not expand forever in the same way.
This could mean big changes for how the universe will look in the future, and it might even hint at hidden dimensions beyond what we can see.
Scientists are excited because this could mean discovering completely new physics.
Latest measurements from DESI suggest dark energy may be decaying or changing over time, rather than being constant.
DESI has created the most detailed 3-D map of the Universe to date, using observations from nearly 15 million cosmic objects.
If confirmed, these findings would challenge the long-standing cosmological constant model of dark energy.
The observations indicate dark energy may have been increasing in the distant past and started to decay around 5 billion years ago.
Further data releases from DESI and new space missions like Euclid and Roman Space Telescope will be crucial to confirm these preliminary results.
- Who
- Scientists using the Dark Energy Spectroscopic Instrument (DESI)
- What
- Released new measurements suggesting dark energy may be changing over time, challenging the cosmological constant model.
- When
- Latest results based on the first two years of DESI observations (DR2).
- Where
- Kitt Peak National Observatory, Arizona (DESI instrument location); probing the universe's expansion history.
- Why
- To map the universe's expansion and understand the nature of dark energy.
Constant Dark Energy (Cosmological Constant Model)
Changing Dark Energy (Dynamical Model)
Dark Energy Behavior
Constant Dark Energy (Cosmological Constant Model)
Dark energy is constant and its density remains the same over time.
Changing Dark Energy (Dynamical Model)
Dark energy's density may be changing, potentially increasing in the distant past and decaying or diluting over time.
Implications for Cosmic Future
Constant Dark Energy (Cosmological Constant Model)
Eternal acceleration and suppression of new cosmic structure formation.
Changing Dark Energy (Dynamical Model)
Profound implications for the future evolution of the universe, including potential slowing down or a different turn in expansion.
- Instrument
- Dark Energy Spectroscopic Instrument (DESI)
- Location
- Mayall 4-metre telescope at Kitt Peak National Observatory, Arizona
- Operational Since
- 2021
- Program Duration
- Five years
- Galaxies Mapped (Program Goal)
- More than 40 million
- Data Release (DR2) Scope
- Nearly 15 million cosmic objects
- Deepest Probed Galaxies
- Over 15 billion light years away