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Study: Dark matter does not exist and the universe is 27 billion years old (www.earth.com)

submitted 8 months ago by saint@group.lt to c/astronomy@mander.xyz

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Heh

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[–] xionzui@sh.itjust.works 13 points 8 months ago (3 children)

This doesn’t answer the question in the context of this theory, but the current understanding is that light does lose energy as it travels through expanding space. As the space it’s in expands, the wavelength gets longer, and the energy goes down. It doesn’t go anywhere; energy just isn’t conserved in an expanding space-time.

[–] HereIAm@lemmy.world 6 points 8 months ago (2 children)

If the light loses energy, then it must surely lose it to something? And if your last point that energy isn't being conserved in our universe, in which case we are either in some deep shit with the first law of thermodynamics, or our universe isn't an isolated system.

[–] atzanteol@sh.itjust.works 8 points 8 months ago (2 children)

Seems energy is not conserved.

https://www.preposterousuniverse.com/blog/2010/02/22/energy-is-not-conserved/

The thing about photons is that they redshift, losing energy as space expands. If we keep track of a certain fixed number of photons, the number stays constant while the energy per photon decreases, so the total energy decreases.

[–] Scribbd@feddit.nl 1 points 8 months ago

Ok. Smarter people probably thought of this, and probably found my hypothesis to be impossible. But what if... It is the the other way around. What if photons are losing energy because they are expanding spacetime. Like tiny little springs expanding out.

[–] Live_your_lives@lemmy.world 1 points 8 months ago* (last edited 8 months ago)

Further into the article he says that, "It would be irresponsible of me not to mention that plenty of experts in cosmology or GR would not put it in these terms. We all agree on the science; there are just divergent views on what words to attach to the science. In particular, a lot of folks would want to say “energy is conserved in general relativity, it’s just that you have to include the energy of the gravitational field along with the energy of matter and radiation and so on.” "

So energy is conserved on the whole, it's just not conserved if you consider photons apart from their greater context.

[–] SkyeStarfall@lemmy.blahaj.zone 6 points 8 months ago* (last edited 8 months ago)

The energy is actually not conserved across the universe in general relativity, as it is currently understood. Conversation of energy is due to the time symmetry, which the expansion of space breaks.

[–] atzanteol@sh.itjust.works 2 points 8 months ago

BTW, thanks! This comment sent me down a fascinating rabbit hole. It had simply never occurred to me that energy conversation didn't apply in an expanding universe!

[–] Live_your_lives@lemmy.world 2 points 8 months ago* (last edited 8 months ago)

“Energy is conserved in general relativity, it’s just that you have to include the energy of the gravitational field along with the energy of matter and radiation and so on.”

Quote taken from Atzanteol's article.