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[-] EggInDisguise 216 points 1 day ago

Take a balloon.

Blow it upto about 50mm

Make a couple dots around it

Blow it up a little more.

Now there's distance between the dots.

Imagine an ant walking between the dots. That ant is going at the speed of light (as fast as it can go) relative to the dots.

Now as it walks between the dots, blow the balloon up really big

The dots aren't moving, they're stuck to the surface of the balloon. The balloon itself is expanding. The ant is going at the speed of ant-light, but now the dots are all "moving away" faster than the ant can walk.

The speed of the ant hasn't changed, the space the ant is traveling has changed. And faster than the ant can move, because the balloon isn't limited by the same things the ant is.

[-] Ichiro_kun@lemmy.world 3 points 12 hours ago

Didn't get it but saving this so when i grow older I'll see it again and think for the logic behind it.. 🗿

[-] yermaw@sh.itjust.works 53 points 1 day ago

Thanks for that that's actually a really helpful analogy.

I mean i still dont understand. Brain hurty. But thanks anyway

[-] sp3ctr4l@lemmy.dbzer0.com 1 points 6 hours ago

Things cannot move through space at a speed faster than lightspeed.

This rule does not apply to space itself.

Also, interestingly, shadow boundaries can 'move' faster than the speed of light.

https://www.iflscience.com/shadows-can-move-across-a-surface-faster-than-the-speed-of-light-75112

Because a shadow isn't truly a 'thing'.

Its just an area where light bouncing off of something is not happening (as much).

[-] capuccino@lemmy.world 34 points 1 day ago
[-] EggInDisguise 11 points 1 day ago

Eventually, the universe itself will "die" when it hits absolute zero and nothing moves anymore. Nothing can happen after the heat death of the universe (unless protons decay)

[-] WormEmperor@sopuli.xyz 11 points 1 day ago

Finally, some good news.

[-] bss03@infosec.pub 5 points 1 day ago
[-] SethTaylor@lemmy.world 10 points 1 day ago

Current data suggest that the universe has a flat geometry

Holyshitholyshitholyshit don't tell flat earthers

[-] Impractical_Island@lemmy.world 4 points 23 hours ago

Not unless you donate some seed money to my church. It will come back to you, and then you pay twice as much and then I pay half. And then you, a vulnerable population, gain faith in the process and give more and more and I give less and less but this is just friendly educational propaganda from your friendly neighborhood juggler and CIA spook.

[-] SirActionSack@aussie.zone 2 points 1 day ago

Yes, and actually right now relatively speaking.

[-] mannycalavera@feddit.uk 17 points 1 day ago

This is a truly great explanation. One worthy of Feynman. Physics degree?

[-] EggInDisguise 13 points 1 day ago

Lmao no, just autistic fascination with space and many thousands of hours of listening to astrophysics lectures and hundreds of hours listening to edu-tainment type videos from people like Dr. Becky Smethurst.

Thanks for the compliment though, I've heard the balloon explanation since I was a child, but the ant-splanation of light speed just popped into my head.

[-] vaionko@sopuli.xyz 1 points 9 hours ago

On todays episode of: University degree or autism?

[-] Korhaka@sopuli.xyz 11 points 1 day ago

The space between atoms starts to expand faster than the speed of light. Well i guess that is the universe fucked.

[-] rockerface@lemmy.cafe 12 points 1 day ago

Good thing the atoms (and the subatomic particles) are pulled back together as the universe expands. The same way we are pulled to Earth by gravity and don't fly off into space as the universe expands.

[-] skulblaka@sh.itjust.works 10 points 1 day ago* (last edited 1 day ago)

This does, however, lead to the existence of "local groups".

Meaning that, there is a local group of celestial bodies that we may theoretically be able to visit at some time in the future, which are held somewhat together by gravitational forces which help to counteract the expansion of space. But anything outside of that local group will be expanding away from the group at greater than the speed of light.

Meaning, effectively, that the universe is going to be / is already separated out into small pockets of local neighbors, who will never be able to reach other local groups unless they invent some sort of much faster than light travel. The universe is very, very large, but the percentage of the universe that is physically reachable by us is quite small, no matter how many generations we spend on the journey.

Personally I find that to be one of the more disappointing true facts about the universe.

[-] SpacetimeMachine@lemmy.world 7 points 1 day ago

Exactly, there will be causally disconnected pocket universes in the future. I'm thankful we still live in a time when we can see the rest of the universe. Creatures alive in 100 billion years might have no way to figure out how the universe started, or that there is anything outside of their local cluster at all.

[-] Tiresia@slrpnk.net 6 points 1 day ago

How fast space expands is described by general relativity. For the space between atoms to expand faster than the speed of light, you need a shitload of energy crammed together very densely, like a galaxy worth of stuff in every atom. This is called cosmic inflation, and it's what happened during (and possibly before) the first part of the big bang.

We don't know exactly how there can be this much energy in this little space, or where it all went, but we do know it was there because there are waves imprinted on the density of the universe.

[-] EggInDisguise 2 points 1 day ago* (last edited 1 day ago)

Without trying to explain things even in not sure I grasp, no. The atomic forces keep atoms together, and expansion of space is only noticeable on long distances. Like light-years and parsecs kind of distances.

Also fun fact: the rate of expansion is not only INCREASING as space expands, last information I saw suggested space is expanding faster in some directions than others, which is fascinating for a number of reasons.

[-] HeyThisIsntTheYMCA@lemmy.world 9 points 1 day ago

courtney you are going to invent rocket ants knock it off

[-] Valmond@lemmy.dbzer0.com 2 points 1 day ago

But space contracts at close to light speed,so your analogy isn't perfect, right?

[-] wholookshere 3 points 1 day ago

No, time contracts, not space.

this post was submitted on 25 May 2026
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