Uploaded April 2024 | Updated September 2026, 2 weeks ago

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DESI, the Dark Energy Spectroscopic Instrument, has just released its first results, and they are not entirely consistent with standard cosmology. In particular, we've been told for decades that the universe's fate is a heat death, with the universe expanding forever into the future. But this assumes that dark energy is constant over time. The new DESI results challenge that. It seems dark energy might weaken over time, maybe even allowing the universe to be cyclic. We unpack what this all means with Kyle Dawson, DESI's co-spokesperson.
Timeline:
0:00 Introduction
0:59 Dark energy
1:57 The DESI instrument
3:47 New results
8:36 I wasn't expecting that
11:26 The Hubble tension
14:16 the fate of the universe
16:08 The future is coming soon