“The idea that dark energy is varying is very natural,” said Paul Steinhardt, a cosmologist at Princeton University. Otherwise, he continued, “it would be the only form of energy we know which is absolutely constant in space and time.”
This more of a semantic question, but I wonder whether dark energy counts as a numinous phenomenon, since if we understood it even in part then the part we understand wouldn’t be dark any more.
I hope DESI doesn't come up with anything that fundamentally changes how we understand the nature of the universe any time soon. I'm only halfway through The End of Everything, and I don't want to have to start over when an updated edition comes out.
Excellent article. As a reader of your book - a changing w over the time is a new chapter, a different end of the universe, no? I must re-read those chapters :-)
Yeah it would be a different evolution. Not sure about different end though — likely would eventually evolve to be essentially one of those discussed
I don’t understand, is DESI observing w ≠-1 or what?
Dark energy violates the law of conservation of energy and requires a no true Scotsman explanation for why it doesn’t.
This stuff fascinates me, but I have little learning in it so I often have trouble fully following articles about it. You allow me to kind of see it, to grasp it, and I appreciate that. Thanks.
So.... Could dark energy be a matrix on which the rest of "reality" is seen?
Kind of like how a collection of data os plotted of graph paper?
Dark energy is the graph paper?
Sometimes people describe spacetime as the kind of grid in which everything else is happening (but it’s a grid that can be warped and distorted) but not dark energy
Someday, after I've bought you and @philplait.bsky.social a drink, I should explain the cosmological implications (as I've reasoned out) for a game setting I wrote, that "explains" Dark Energy in that universe.
You'll be amused, horrified, or start brainstorming...
I've been wondering this for a long time about dark energy: It's always described it as a force expanding the fabric of space at an accelerating rate, working against gravity.
Is literally *everything* expanding? You, me, etc? Or is it space expanding and pulling stuff along with it?
Is there a layman's explanation as to what, if anything, the universe is expanding into? Assuming the Big Bang, what surrounded the infinitely dense something that contained all the matter that makes up the universe before it went "BOOM"?
It's not expanding into anything. It's the already existing space expanding to be larger.
At the big bang the infinitely dense was surrounded by more infinitely dense, and all of it started to expand. It wasn't an explosion from a single point at a specific location, it was an expansion everywhere
I think the answer is "nothing" but I don't think anyone knows for sure...yet. The "infinitely dense something" was all that there was, and still is, just a bit more spread out now.
“Infinite and getting more infinite” broke my brain at first, but then the explanation of the universe maintaining the same amount of matter but becoming less dense made it all make sense.
No it just means that the amount of dark energy in you is not enough to unbind the material that you’re made of. Same is true for galaxies (which are bound by gravity rather than molecular bonds).
As things fragment it feels like an increase in dark energy, not less, widening the gaps. Unless the problem is really a kind of gradual densification, with a higher propensity for collision. Whichever, it seems like time is speeding up.
OK, I am going to test my very primitive understanding here, which is: Yes, the space a person occupies is expanding, but it is doing so at such an incredibly small rate (on that scale) that the electromagnetic forces that keep us together can easily overcome it. On a larger scale, same for gravity.
Thanks for your answers. I think one of the confusing things about inflation is that it's not just expanding radially from some central point, but it's just...all expanding.
What's weird to me is as the universe expands, so do the yardsticks...a mile is still a mile, right?
But when you blow into a balloon…. you blow more air particles into the balloon. The amount of stuff in the balloon is literally increasing. Space isn’t like this. The amount of matter in space isn’t increasing (at least, that’s my understanding!)
My wife's step-brother-in-law is a dark energy guy. Maybe named it? Michael Turner. The couple of times we've got him to tell us about it at holidays have been cool.
Comments
“The idea that dark energy is varying is very natural,” said Paul Steinhardt, a cosmologist at Princeton University. Otherwise, he continued, “it would be the only form of energy we know which is absolutely constant in space and time.”
Can the possible DESI result even be considered a successful prediction of the string theory?
(Or at least a version proposed by Vafa and Steinhardt, among others.)
But seriously, that's cool.
https://youtu.be/JUOGxePBs50?si=9pn15f1Hp0k57QWy
Dark energy violates the law of conservation of energy and requires a no true Scotsman explanation for why it doesn’t.
Kind of like how a collection of data os plotted of graph paper?
Dark energy is the graph paper?
You'll be amused, horrified, or start brainstorming...
Also, Dark Energy should be your band Transit Authority's first album title.
I may have had too much coffee and ice cream.
Is literally *everything* expanding? You, me, etc? Or is it space expanding and pulling stuff along with it?
At the big bang the infinitely dense was surrounded by more infinitely dense, and all of it started to expand. It wasn't an explosion from a single point at a specific location, it was an expansion everywhere
Does that mean there's no dark energy in me?
That feels like a therapy question, not physics, but here we are.
The amount of material in the balloon does not change, but as you blow it up more and more, it gets bigger and bigger
It also, from this, gets thinner and thinner as a structure
Free idea for scifi writers out there - what happens when that wall breaks open
What's weird to me is as the universe expands, so do the yardsticks...a mile is still a mile, right?
A mile is just an arbitrary distance between Point A and Point B. Regardless. The distance between those two points doesn't necessary change
But the space those points are IN sure can move, and that's what's expanding
Which...isn't really any easier to wrap ones' head around, sadly