Well, nothing (with nonnegative mass) can move faster than light through space. Space itself can do whatever it wants to.
wat
Submitted 3 weeks ago by Stamets@lemmy.dbzer0.com to memes@sopuli.xyz
https://lemmy.dbzer0.com/pictrs/image/a75d185b-10af-44cd-afbc-8a88333d95e8.webp
Comments
Chrobin@discuss.tchncs.de 3 weeks ago
booscience@beehaw.org 3 weeks ago
Well, the thing space is moving into and across
BurnedDonutHole@ani.social 2 weeks ago
I don’t know why maybe the painkillers are speaking but I have to ask, does farts count as negative mass?
I’ll take my leave…
ᕕ(ᐛ)ᕗ
OwOarchist@pawb.social 2 weeks ago
Okay … enjoy your painkillers, man.
Incoming vibe killer: no, farts do not count as negative mass. They do in fact have positive mass. You will weigh ever so slightly less after farting. And, in theory, if you were in a frictionless environment, you could propel yourself by farting, because the fart’s mass would act as a reaction mass and propel you like a (very weak and stinky) rocket.
Kolanaki@pawb.social 2 weeks ago
The universe is mostly nothing. So obviously the universe, being nothing, expanding faster than the speed of light isn’t surprising, as nothing is faster than light. 😌
LovableSidekick@lemmy.world 2 weeks ago
Wrong, the expansion isn’t motion. But you have to think about it longer than you’re going to want to before hitting the up or down arrow and/or scrolling.
rektdeckard@lemmy.world 2 weeks ago
Best intuition I’ve heard for this is that “things” can’t move faster than light, but not everything is a “thing”.
Imagine doing shadow puppets on the wall with a flashlight. You move the bunny left, shadow moves left. The further away the wall is, the faster the apparent speed of the shadow bunny. You might think that, far enough away and with a strong enough light, your shadow bunny would be racing across the sky faster than the speed of light – and the crazy thing is, you’d be correct! The shadow (absence of light) can move arbitrarily fast. But the light itself is moving at its normal constant speed from the flashlight out into space, perpendicular to the travel of the bunny, like a garden hose spraying water. The time it takes for the shadow to even begin to move is governed by the speed of light. No information can be communicated faster than light because the light travels at the speed of light to illuminate the places where the shadow isn’t.
LovableSidekick@lemmy.world 2 weeks ago
Very eloquent explanation. The one glitch I must point out is that the shadow (or absence of light) can’t move faster than light, because the shadow is information and information can’t travel faster than light. If it could, you could use a sequence of shadows, coded by length and spacing, for FTL communication.
crapwittyname@feddit.uk 2 weeks ago
Best analogy I heard for it is if you put a load of dots on a balloon, then inflate it. Are the dots getting further away? Yes. Is there just the same amount of rubber between each dot as when you put the dots on? Yes. Can you measure the relative speed of the dots? Yes! But have they actually gone anywhere? No…ish?
kamen@lemmy.world 2 weeks ago
Yeah, but in this case is the universe just the dots on the surface of the balloon or is it the whole balloon with its entire volume? Intuitively I think it’s the latter (although there’s probably no “hard” edge that’s bounding the ends of the universe like the rubber of the balloon), and if that’s true, you could measure the speed of one wall getting away from the centre or the speed of two opposite walls getting away from each other.
I could be wrong of course, I’d be happy if someone points out what I might be missing.
plutopos@lemmy.zip 2 weeks ago
Understanding this is the easy part imo
LovableSidekick@lemmy.world 2 weeks ago
Great analogy, and yeah the “ish” is the fun part!
Impractical_Island@lemmy.world 2 weeks ago
You can explain but don’t but criticize you are idoltarer and are in degenerate dharma like all Christians nowadays
starman2112@sh.itjust.works 2 weeks ago
Preemptive explanatory note: the speed of light, approximately 300,000 km per second, is the highest speed that something can move through space.
The expansion of space doesn’t happen at a set speed. It happens at a rate of approximately 70 km per second per megaparsec. So if you’re measuring two points half a megaparsec away from each other, then every second, the space between them grows by about 35 km. If you’re measuring two points 2 megaparsecs away from each other, then every second, the space between them grows by about 140 km.
If you’re measuring two points 4300 megaparsecs away from each other, then the spacetime between them grows by about 300,000 km every second. That’s not to say that anything is moving at 300,000 km per second, there’s just more space between them every second
starman2112@sh.itjust.works 2 weeks ago
Wtf is a megaparsec? It’s a million parsecs. Tf is a parsec? A parallax arcsecond.
…Tf is a parallax arcsecond?
An attempt at an explanation for the layperson
Imagine you’re standing outside. In front of you is a tree and behind that on the horizon is a mountain. You move 10 ft to your left, and the tree looks like it moved to the right, but the mountain looks like it hasn’t moved at all. That’s parallax. The closer something is, the more it appears to move when you move. Imagine you are the pivot point on a big protractor. Your field of view can be divided into 360°. Every degree can be divided into 60 parts, called arcminutes. Every arcminute can be further divided into arcseconds. Each arcsecond is 1/3600 of a degree. How do these fit together? There’s one more thing I need to explain. The earth orbits the sun at around 149.6 million kilometers. That’s called an Astronomical Unit. A parsec is the distance that an object would have to be, so that moving one Astronomical Unit would make it appear to shift sideways by 1 arcsecond.
It’s 3.26 lightyears.
vivalapivo@lemmy.today 2 weeks ago
just more space between
Space out of thin air… tell me, mate, can I sell it?
rumba@lemmy.zip 2 weeks ago
NFT’s sold, so probably yes
LovableSidekick@lemmy.world 2 weeks ago
Beautiful! That was the explanation I was trying to come up before giving up and just saying the expansion doesn’t have a speed because it isn’t motion, which is only partially correct.
niktemadur@lemmy.world 2 weeks ago
This guy expands!
plutopos@lemmy.zip 2 weeks ago
Moving is just putting more space between you and something. If it walks like a horse, talks like a horse, bites like a horse… you get the idea. It’s not clear to me why the increase of inbetween space in cosmic inflation “gets a pass” whereas the increase of inbetween of space from movement doesn’t
starman2112@sh.itjust.works 2 weeks ago
Apologies for the wall of text. I spent an hour and a half trying to find the most concise way to explain this, and there kind of isn’t one…
An attempt at an analogy
A submarine increases its depth by sinking lower in the water, right? Imagine a tub of water 1 foot deep. Put a toy submarine 6 inches from the bottom, and it’s 6 inches underwater. Now add another six inches of water to the tub. Your sub hasn’t moved through the water at all, but now it’s 1 foot deep. The submarine can increase its depth without sinking at all. In fact, if you let the submarine rise slower than you add water, then it can rise upward through the water as it continues to get deeper below the surface.
There are two ways for the distance between two objects to increase
There are two ways for the distance between two objects to increase over time. One of them involves displacement through a medium, and the other involves that medium itself expanding. From our perspective, a galaxy 5000 megaparsecs away is “moving” away from us by about 350,000 km every second, but that’s only because for every megaparsec between us, the space itself is expanding by about 70 km every second. If you ask a guy smack in between us, he’ll say we’re both moving away from him at 175,000 km every second. That galaxy isn’t experiencing any acceleration in that direction; it isn’t moving through space at that speed.
The speed of light is a constant
The speed of light (in a vacuum) is a constant. That is to say, every observer in every reference frame measures every photon (in a vacuum) as moving at 299,792,458 meters per second. This fact supersedes all others. It supersedes time itself. Imagine I’m on a train going 50 mph, and I throw a ball forward at 50 mph. In my reference frame, that ball is going 50 mph. To an outside observer, that ball is going 100 mph. How fast the ball is going depends on your frame of reference. This is not true of light. If I’m traveling on a train going half the speed of light and I shine a flashlight forward, the train’s speed doesn’t add to the light’s speed. You and I will both agree that those photons are moving 299,792,458 meters every second, in both our reference frames. This happens because we aren’t experiencing the passage of time at the same rate. The photons coming out of that galaxy 5000 megaparsecs away are also going 299,792,458 meters per second in our reference frame, even as the space between us grows by more than that in that amount of time. That galaxy isn’t moving faster than light, space is just expanding.
treesquid@lemmy.world 2 weeks ago
In the same way that two cars driving away from each other at 60 mph have relative speeds of 120 mph with regard to each other, yes. Everything in the universe moving away from everything else and sometimes at relative speeds that exceed the speed of light. Nothing is exceeding the speed of light in absolute terms.
Objection@lemmy.ml 2 weeks ago
That’s intuitive but actually completely wrong. There is no “absolute” reference frame, and nothing can move faster than light in any relative reference frame.
The only thing that gets around that is the expansion of space itself. It’s not that the objects are moving away from each other, it’s that the distance between them is expanding, causing them to become farther apart.
The best analogy is to picture an ant crawling on the surface of an expanding balloon. If the balloon keeps expanding fast enough forever, the ant won’t be able to make it from point A to point B. It’s not really that the ant is moving away from point B, it’s just that the distance is expanding faster than it can move.
Rooster326@programming.dev 2 weeks ago
Okay but the ant can still only go at the speed of ant.
Luna@ani.social 2 weeks ago
Relative speeds also cannot exceed the speed of light. Since there’s no absolute reference frame, if this were possible it would be no different than exceeding the speed of light on “absolute” terms. Once you get up to speeds where this would matter, funny dilation effects that I’m too dumb to understand would prevent this.
childOfMagenta@jlai.lu 2 weeks ago
Cars are not driving away from each other at more than the speed of light. The road is stretching faster than the speed of light.
baguettefish@discuss.tchncs.de 3 weeks ago
my personal headcanon is that the universe is a giant living being and we are its fundamental particles or some other infeasibly tiny thing
Duke_Nukem_1990@feddit.org 2 weeks ago
I have had thoughts like that before! Especially since at school the atomic model that was taught looked like a little galaxy (which I now know is inaccurate) and it seemed like going smaller or going bigger just repeated similiar patterns, so to say.
skulblaka@sh.itjust.works 2 weeks ago
“As above, so below” is a pattern that’s almost universally recognized for a reason. The galaxy atom model may not be accurate, but lots of things in the world rhyme at different scales.
jimerson@lemmy.world 2 weeks ago
When I was a kid I imagined that our universe and every galaxy in it make up a single atom in another, much larger universe.
That much larger universe, in turn, is also a single atom in a much larger universe. And so on…
mattyroses@lemmy.today 2 weeks ago
Dark Tower did the same bit as well
TeamAssimilation@infosec.pub 2 weeks ago
Thank you! I used this weird thought to wipe my brain from other weird thoughts, it needed that.
El_guapazo@lemmy.world 2 weeks ago
The speed of dark is faster than the speed of light
Knock_Knock_Lemmy_In@lemmy.world 2 weeks ago
Light thinks it travels faster than anything but it is wrong. No matter how fast light travels, it finds the darkness has always got there first, and is waiting for it.
Terry Pratchett
HrabiaVulpes@europe.pub 2 weeks ago
Explanations why space expands are way more crazier than this.
DmMacniel@feddit.org 3 weeks ago
Well duh. When a thing moves away from another thing, that is moving at the speed of light, at the speed of light, you have speed of light time two!
TheTechnician27@lemmy.world 3 weeks ago
This explanation is the wrong intuition for why space can expand FtL. It’s an understandable one to infer, but the balloon one further down is correct and the one most commonly used by cosmologists for a lay audience.
Our current understanding of cosmological expansion works by Hubble’s law, and that equation puts no such 2x cap on the recession speed.
OrganicMustard@lemmy.world 2 weeks ago
You still have one speed of light, that’s the Lorentz transformation
rumba@lemmy.zip 2 weeks ago
besides the expansion of spacetime which is the correct answer, there’s also nothing keeping two objects from traveling in opposite vectors each at 60% c. Frame of reference matters too
MajorasTerribleFate@lemmy.zip 2 weeks ago
The very short, very bastardized version is that as objects move at speeds closer to the speed of light, the way everything else around them appears to be shaped and moving changes. A “stationary” object you pass seems less long than it should in the dimension parallel to your travel. The net result is that however two objects are moving relative to each other, their own speeds warp their experiences of the universe such that nothing else is observed to be doing something “illegal”.
PhAzE@lemmy.ca 2 weeks ago
No, spacetime doesn’t expand faster than light at any point. Its just that as you accumulate the new growth over a long distance, the farther objects appear to move away faster than light from our position.
GiveOver@feddit.uk 2 weeks ago
There actually are things keeping that from happening but I don’t want to get into it
EvilHankVenture@lemmy.world 2 weeks ago
I may be wrong, it’s been a while since I looked into relativity. But I think it’s possible from an outside perspective to see 2 objects that have a velocity relative to each other that is faster than the speed of light.
If 2 spacecraft travel in opposite directions at 60% of the speed of light from the earth it would appear that they are traveling away from each other faster than the speed of light. From either ship it would not appear that the other ship was traveling faster than the speed of light however.
BurgerBaron@quokk.au 3 weeks ago
That’s so no matter how much knowledge we gain we can never escape the bad place to kill the Demiurge.
baconsunday@lemmy.zip 2 weeks ago
I remember finding out the shape of space isn’t a vast plane of emptiness, but more of an ever growing sphere and that messed me up.
BrazenSigilos@ttrpg.network 2 weeks ago
Nothing within the known universe moves faster then light, but the universe itself expands faster then light travels within it.
Prontomomo@lemmy.world 2 weeks ago
We should probably use the word “growing” instead of “expanding”, would that be easier to follow 🤔
Olhonestjim@lemmy.world 2 weeks ago
Shadows can move faster than light.
omega_x3@lemmy.world 2 weeks ago
Quantum entanglement is faster than light
db0@lemmy.dbzer0.com 2 weeks ago
Since nothing can move faster than the speed of light doesn’t it also mean that the universe cannot be expanding faster than 2e either?
IAmNorRealTakeYourMeds@lemmy.world 3 weeks ago
Fuck it, question that I had since 10 years old.
if I have a very long stick, and I flick it. what would happen to the tip? what if a laser pointer is used? at a certain distance, the beam would be moving (sideways) faster than light.
it might work better with a whip rather than a solid stick.
Blue_Morpho@lemmy.world 3 weeks ago
A shadow can move faster than light too.
M137@lemmy.today 2 weeks ago
How to tell people you don’t know more than school level basic science: the person who made that image and OP making this thread.
All you did was write “hey, I don’t comprehend things that are easily learned and have been freely available to learn from your own home via the Internet for several decades” on a sticky note and put it on yoir forehead, then went into a public place for everyone to see and somehow didn’t realise you did any of that.
possiblylinux127@lemmy.zip 2 weeks ago
I don’t think it is
EggInDisguise@lemmy.blahaj.zone 3 weeks 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.
yermaw@sh.itjust.works 2 weeks 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 2 weeks 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.
iflscience.com/shadows-can-move-across-a-surface-…
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 2 weeks ago
All we are going to die?
WolfLink@sh.itjust.works 2 weeks ago
Yes
EggInDisguise@lemmy.blahaj.zone 2 weeks 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)
Impractical_Island@lemmy.world 2 weeks 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.
mannycalavera@feddit.uk 2 weeks ago
This is a truly great explanation. One worthy of Feynman. Physics degree?
EggInDisguise@lemmy.blahaj.zone 2 weeks 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.
Korhaka@sopuli.xyz 2 weeks 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 2 weeks 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.
Tiresia@slrpnk.net 2 weeks 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@lemmy.blahaj.zone 2 weeks 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.
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 2 weeks ago
courtney you are going to invent rocket ants knock it off
Ichiro_kun@lemmy.world 2 weeks 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… 🗿
Valmond@lemmy.dbzer0.com 2 weeks ago
But space contracts at close to light speed,so your analogy isn’t perfect, right?
wholookshere@lemmy.blahaj.zone 2 weeks ago
No, time contracts, not space.
kevin2107@lemmy.world 2 weeks ago
WHOS BLOWONG UP THE BALOON AND WHEN WILL IT 💥
DancingBear@midwest.social 2 weeks ago
Can I imagine a tardigrade instead?
Ichiro_kun@lemmy.world 2 weeks 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… 🗿