Bittersweet Candy Bowl

I love flatland

Well, since the 4th dimension is Time, I would assume that the 4th defining part of a 4D cube would be that it exists on multiple levels in time.

No, Modern Physics has declared that time and space are combined into “spacetime”, and due to that, time is no longer classified as a dimension.

Well then, there are no longer 10 dimensions, rendering many theoretical physicists’ jobs pointless. Well done, Jimmy

However, my theory still stands, as the cube would still exist in space and time, and so you have just condensed the theory behind it slightly.

@ Jimmy - That don’t make no sense. It’s an infinite line on which you can be located. That’s mine and my logic’s definition of a dimension. Well, whatevs.

@ILB: The “white hole” you mentioned is the theoretical exit from the black hole into the other universe.
Intersting fact about Tesseract. Anything which exists in the fourth dimension can “wrinkle” space, creating a sort of warp effect. For example, picture a wall with no passible way. This is the space. In order to get past the wall, you must climb over. Think of climbing as the now-shortest distance, a straight line between the two points. Now, add a door to the wall. The door is the wrinkle in the spacetime, and allows you to bypass the distance completely. This is known as the act of “Tessering”, and is featured in the utterly fantastic book “A Wrinkle in Time”.

@Jimmy It wasn’t abolished, it was just renamed as the Minkowski Space, a dimensional plane that includes time, where Einstein’s Unified Field Theory can be applied practically.

The largest planet currently discovered is named TrES-4. It is aroud 1,400 light-years from Earth, and roughly twice the size of Jupiter. The odd thing about it, however, is it’s density, estimated to be about that of balsa wood.

I always find it wierd how they find planets and study them in different solar systems. I mean, even the hubble telescope can’t see planets that far away, they can only see stars. Even looking at a planet orbiting Proxima Centauri (closest star to the sun) would be impossible with today’s technology.

There’s interesting methods for discovering planets based on the wobble of the stars they orbit and possibly find the mass, too, but how the hell can they find things like the volume, density and conditions of these planets??

Here’s an interesting thought experiment involving relativity, as it relates to the speed of moving objects.

Consider this:
1. All velocity is relative. It can only be accounted for as the difference in velocities of two objects.
2. The speed of light is the maximum theoretical velocity at which any object can be moving, in relation to another object.

Now imagine two particles are moving from the same point very far away, towards the earth. Relative to the earth, both particles are travelling at the speed of light (or very near it). However, because velocity must be relative and the maximum relative velocity between any two objects is the speed of light, we can also concieve that - relative to each other - the particles are moving at different speeds. We could even stretch or mind experiment to say that on particle is traveling at the speed of light, relative to the other. This generates a few interesting scenarios.

1. Which particle will arrive first on earth, if any? Considering, relative to earth that they have the same velocity.
2. What would be observed from the perspective of (a) Earth, (b) the first particle and (c) the second particle?
3. What would an “outside observer” at another velocity observe?

Some really mind-boggling concepts.

@Migrant

There are 4 interpretations of your experiment (I consider particles negligibly close to each other):

1. They have _exactly_ the same velocity relative to Earth, but less then the speed of light. Let’s say v. This means they have 0 velocity relative to each other.
1)They arrive on Earth at the same time.
2) (a)The Earth sees them as moving at v towards it.
(bc)They see each other as stationary, and Earth moving towards them at v.
3) An outside observer would see two particles moving together at the same speed and colliding with Earth moving at a different velocity in a (possibly) different direction. Knowing the observer’s velocity we could calculate exactly what velocities he sees.

2.They move at slightly different speeds towards Earth, still less then speed of light. Let’s say from particle A’s point of view particle B moves at 5000 km/h towards Earth, and from Earth we see A move at v.
this means
(a) Earth sees B moving slightly faster towards it and arriving first. If A and B are close to the speed of light the difference in velocity can be as little as 1cm/h but it’s still there and B is faster.
(b) A sees B moving towards Earth at 5000 km/h and Earth moving towards them at v.
(c) B sees A move away from Earth at _exactly_ the same 5000 km/h. And B sees Earth moving towards them at exactly the speed Earth saw B moving in (a).\
(v+1cm/h)

(d) An outside observer, if he doesn’t move parallel to the particles, sees Earth flying somewhere and two particles flying from the same spot in _different_ directions at different speeds that both happen to hit Earth in turn. And B still hits Earth first.

3. If they move at the speed of light (c), you can’t consider their velocity relative to each other, because reference frames can’t move at the speed of light. If you move at the speed of light you can’t observe anything.
1) They hit Earth at the same time.
2) (a) they move at c towards Earth and hit it.
3) Earth is flying somewhere. The particles move at c together and hit it.

4. B’s velocity is c. A’s velocity is v (relative to Earth).
1) B hits first
2) (a) From Earth’s point of view: B flies at Earth with velocity c, A flies at Earth with velocity v. B hits first.
(b) From A’s point of view. Earth flies towards A with velocity v. B moves towards Earth with velocity c. B and Earth collide, then Earth hits A.
(c) Not considerable.
3) An outside observer would again see two particles leave the same spot in different directions with different speeds: A with some v1

Sorry forgot how the forum handles less-then marks as parts of tags.
…
3) An outside observer would again see two particles leave the same spot in different directions with different speeds: A with some v1 (less than) c, and B with c. Then they proceed to hit a moving Earth, first B then A.

Special relativity is not that mind-boggling. Now imagining how a spinning charged black hole is different from a spinning non-charged black hole is augh-my-brain-hurts.

Know what’s cool? Horsehair worms.
Nothing like host altered behavior for drowning in order to continue the life cycle to start your morning.
Also. Syphilis. Consider host altered behavior here.
But I digress I must be off to work.

@Migrant The telescope doesn’t see the planet directly, but, as I’m sure you know, everything has a gravitational pull, however small. Planets can be detected by looking at a star’s spin, and if there are fluctuations then it means that something is pulling it, which is most likely a planet.

I guess my example wasn’t very good, what with speed of light being kind of a maximum and equal to all observers. But even at relatively close to the speed of light, volume and shape and distance and time can appear to change in strange ways. What I was trying to show was Relativity of Simultaneity, in which events can seem to be simultaneous for one observer, but occur one before the other for another, and change orders for a third observer, depending on their relative motions. This holds true as long as the evens are not occuring in the same space.

Yeah Sammy, i know, but you could at the very most estimate the planet’s mass from that, not any info about volume, density and chemical make-up.

“sigh” i supose i’ll save this thred for Mig.

@Mig now no more homaphobia for you, you hear me

Is it possible to travel at the speed of light? I thought that when you reached light speed your mass would increase until you slowed down.

That is generally true, HB, but sub-atomic particles can be accelerated to very very near the speed of light.

Dem tachyons. DEM TACHYONS. They annoy me on a level I can’t comprehend, mostly because I only just heard about them. Any info, please? Something about travelling faster than light, simply because they do. Then there’s all the stuff about the Higg’s Boson, and CERN’s work on finding it, and why it’s the God Particle and all.
On a completely different note, the Double Slit experiment always impressed me. In a tl;dr sense it’s an experiment where photons somehow stay in two places at once, also in no places at once, Schrodinger’s Cat style, but the physical act of observing the photons influences them to make up their minds and go one of the slits. Who doesn’t find that absolutely staggering?
This is all pretty new to me at the moment, seeing as my science lessons are covering covalent bonds and how to draw out a results table for maximum marks. Fun stuff.

So, physics, chemistry or biology?

Tachyons are a THEORETICAL, made up and not-to-be-taken-seriously particles that travel backwards in time (or faster than the speed of light, depending on context). They are useful as plot devices in cheap science fiction novels and superhero comics.
Summarised info on the Tachyon

The double slit experiment is really awesome, you’re right (Though not as awesome as the double SLOT experiment, hur hur hur). To be honest, physics isn’t really my area of expertise, i’m chemistry / biology oriented, but the whole quantum thing is just too cool.

Changin the topic to something more day-to-day, a fun fact about cats:

The time a cat needs to right itself when falling means a cat can only land the right way up when it falls from more than 1 metre (~3 feet).

Also, Cats falling from more than 20m height have a better chance of surviving and break fewer bones on average, than cats falling from a height of 12 - 19 metres. The reason is that this is how much it takes for a free-falling cat to reach terminal velocity. Once cats reach terminal velocity they relax their muscles and spread out their limbs more, thus increasing air resistance (and reducing speed) and increasing the area of impact once they reach the ground.