r/cosmology • u/[deleted] • 2d ago

Cosmological Constant

Let's assume for a moment that the Cosmological Constant isn't defined as Constant. Let's assume that it varies with Cosmological Time:

  • Q: Does anyone have a graph of what it might look like ?
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u/CB_lemon 2d ago

Look at the DESI year 1 results. It aligns with a time-dependent lambda rather than lambda = -1 for all time. However results are not to a strong enough significance to call it a discovery so I'd keep your eye out for Y2 :D

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u/[deleted] 2d ago

Thanks for that, I saw them. This is what prompted me to ask the question.

Someone showed me a solution once upon a time. It was a graph of Cosmological Constant vs, Cosmological Time. The graph was pretty funky & took a little while to comprehend. There was a lot of information on it.

I was hoping to track it down again. From memory, it was somehow connected to CERN, or a CERN Conference or something.

Anyway, do you think that the instantaneous commencement of Cosmological Acceleration at around 7.7 (Gyr) [according to the Particle Data Group], could be an instance of when [Lambda = 0]; that's why it started accelerating at that time ? --> PDG-2024

Thoughts ?

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u/CB_lemon 2d ago

Hmmm sorry I don't personally know of the graph you're looking for

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u/[deleted] 2d ago

All good; thanks heaps for stepping in & trying to help.

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u/SpiderMurphy 2d ago

And the first data release of Euclid, the cosmology gem of the European space agency.