Sean Carroll Answers Your Questions - Ask the Experts #19

Sean Carroll, theoretical physicist at Caltech and author of Eternity to Here: The Quest for the Ultimate Theory of Time, answers your questions!

Questions:

1. If we did travel at 99.9% the speed if light what would it look like? And i read that we could create something like a warp drive to travel without breaking the laws of physics is this true? —Tyler Claudio

2. Micheal said in video 3 that if you traveled over the speed of light you would go back in time but a human cant go the speed of light so could a object or machine could go faster then the speed of light would it appear in the past? —Cam Nelson

3. Is there a timeless zone in the universe? —Santy Arcusa

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Leave your questions in the comment section or ask it in a video response. An expert will be back to answer 3 more of your questions. Thanks for watching!

[trevormcquoid]

This guy is really good at explaining things

[siddheshpatil]

What is the primary season for the formation of a blackhole ?
1. A huge compression? OR
2.A black dwarf's explosion ?

[lewisdanson]

I've heard from Vsauce's video entitled: 'How Much Does a Shadow Weigh?' that Light (Photons) travels slower through different materials... Such as, water, glass, diamond etc. But if Photons have no mass then why do they go slower through different materials?

[noughk]

thats because that equation comes from newtonian mechanics, and is very accurate for describing the interaction of masses, however, gravity isn't a force, but rather a warping of space that causes a straight line to become curved, that is why it has an effect on massless things as well.

[ErnieC]

The angular speed of the "laser dot" would make it appear that it was traveling faster than light, but the actual photons are still traveling straight out (not panning). Scientist have observed similar effects, where a mass ejection from a star appears to have an angular speed representing super-light speed, but it was discovered that it was actually moving at them, making the false appearance of super-light speed.

[beatthebag]

If I understand Everett's Many Worlds theory correctly, it suggests that all possible outcomes of a quantum state happen simultaneously. In other words more then one reality is happening at a single point in time. Which in my mind requires a fifth dimension of space.

[koma]

youre awesome bro. This stuff is great.

[Draftgon]

I don't remember where I caught this up, but the moon is infact getting further away.
Not trying to boast here but the new spacelab video just answered that question by the way.

[pooley]

I've read somewhere that when the tidal friction process is complete, the Earth will rotate synchronously with the Moon with about a 60 day "month". That the Earth rotational eneergy is not sufficient to drive the Moon completely clear of the Earth.

This probably happened to the Moon a long time ago--if it ever rotated that was stopped by the 80 times stronger tidal effect on the moon (Earth mass 80x that of Moon)

[goldstud]

If we took every magnet on earth and placed them in one spot on earth could we change the earths rotation and or gravitational pull?

[JUNAID]

How would we overcome the issue of high speed collisions when traveling at high speeds? We keep hearing there's lot of debris in space and rocks and even small meteorites floating around which would obviously damage a spacecraft severely at high speeds.

[beatthebag]

One would assume if there was electrons, quarks etc. (regular matter) in another universe it would not be effecting ours (because by definition it would not exist in our universe it would exist in it's own universe)

[wdrun]

you don't get old, as you move closer to the speed of light, you jump further in to time, in a sense, so everything outside of your speed is getting older, but you stay roughly the same age.

[EntangledQuanta]

the reason people keep asking about it is because it is a barrier to human exploration and expansion. somewhere along the line we evolved with the desire to overcome barriers. so far, all questions about this particular barrier have met with unsatisfactory answers. we'll keep asking until we get an answer we want to hear.

[EntangledQuanta]

That would depend on how much the moons orbit changed due to its changed mass. When you add mass you'd also have to take into account the orbital velocity of the mass and add it to the mass and velocity of the moon. If you wanted to know how fast they orbited each other you'd have to know mean distance - assuming the orbit is stable. If the distance stays the same as it is now I think orbital escape velocity is 17, 500 mph. That would mean about 45 min night and 45 min day.

[wdrun]

because of gravity, gravity does not only focus on one spot it is all around, for example, where you are sitting right now the pull of gravity is 9.8 m/s and if you go to the other side of the world the pull of gravity is 9.8 m/s. It is the same for every other spherical object, they just have different gravity pulls

[tonton]

if it was possible for us to time travel through going beyond the speed of light, what would the surroundings look like as we travel and where would we land if we reached the past?

[noughk]

Light does funny things around blackholes as well, for instance if something was at the correct distance behind one, we would see it as a expanding to a ring around the black hole, and then reforming to a planet or star when it moved in front.

[jrandallec]

The gas at the center is most likely a superfluid and anything travelling at that speed would probably just break up and burn up in the thick atmosphere. If it were to hit the superfluid center it would hit and the fluid would act as a solid.

[newemnem]

If the universe is expanding, it must have an edge. So at this edge, how does matter form? Does it just appear or is everything in the universe expanding at the same pace relative to everything?