#Relativity

[prokopetz]

Kerbal Space Program was once afflicted by a bug the fans dubbed the "Deep Space Kraken", whereby if you travelled far enough from the origin of the game's coordinate system, floating point rounding errors would cause your spacecraft's components to become misaligned and/or clip into each other, resulting in the craft falling apart or exploding for no obvious reason.

The bug was later fixed by defining the active spacecraft itself as the origin of the game's coordinate system. In effect, the spacecraft no longer moves; instead, the spacecraft remains stationary and the entire universe moves around it. Owing to how relativity works, to the player this is indistinguishable from the spacecraft moving about within a fixed coordinate system, and it ensures that the body of the craft and its components will always be modelled with maximal precision.

While elegant, this solution introduced a new problem: it was now possible, by doing certain stupid tricks with relativistic velocities, to introduce floating point rounding errors to everything except the active spacecraft. In extreme cases, this could result in the destruction of the entire observable universe.

Some might call this one of those situations where the solution proves to be worse than the problem. I call it a perfect expression of what Kerbal Space Program is truly about.

[todays-xkcd]

It says to cut the onions into 1/4" slices, but I'd better correct for length contraction.

Recipe Relativity [Explained]

[toastydumpster]

time loop shenanigans

1 - 2 for the @malevolentbigbang !

Death of The Arthur by @tallangrycockatiel was a delight to read !!!

I had the honor to pair up with @aktrashpanda and @whynotlol9 so please check out their pieces as well!!

ID (thank you Jack) under read more :>

[ID: A recreation of "Relativity" by by M.C. Escher. It includes multiple iterations of Arthur and John in a room made of seemingly nonsensical corridors, rooms and stairs. They're alternatively walking, sitting, and waiting. /End ID]

[dark-rx]

(via Pin page)

[spaceexp]

Relativity and Grand Theories

From the book DK Ultimate Science Knowledge Encyclopedia

[noosphe-re]

Gravitation by Charles W. Misner, Kip S. Thorne, John Archibald Wheeler

[facts-i-just-made-up]

What does E = mc^2 actually mean?

Let's start at the very beginning, A very good place to start. When you read, you begin with A-B-C. In science, you begin with E and MC:

E, a quantitative property.

M, the mass of something there.

C, a speed as fast as light.

2, that stands for something squared.

So, if mass and light combined-

Square, and equal energy,

Then, in relative spacetime-

That will bring us back to E equals MC (squared).

That's all in a musical by Rodgers and Einstein of course.

[agent-troi]

big mood sam

[digitalfossils]

[secondwheel]

TIME- from different perspectives

[blossominthewoods]

We grow to know that we don't know. And that is all we truly need to know.

[not-a-fucking-mermaid]

Hello! I have a physics related question, specifically about special relativity and the relativity of simultaneity. And I haven't been able to find the answer anywhere so i'm hoping the science side of tumblr will help me out here. (and forgive me if i'm using incorrect phrasing here, english is not my first language and i'm just now *actually* learning about relativity, but i hope you're able to understand my question anyways)

Yk the train-and- platform paradox?

What I don't understand is why person A (on the train) sees the lightning strikes at different times just because in person B (on the platform) predicts they will (because B is perceiving the event from their own reference frame). This whole thing seems based on the assumption that person A and person B agrees that one of them sees the lightning at the same time and the other at different times, but I don’t understand why that is a correct assumption to make. If person B sees the lightnings at the same time, then they conclude they happened at the same time. And if they did happen at the same time, person A would in their own frame of reference also see the lightnings at the same time. So why does person A see the lightnings at different times just because that’s what would have happened in person B’s reference frame?

[thedifferentialequationsboy]

black holes aren't black (with caveats)

The name is such a misnomer! In fact black holes in our universe tend to be some of the brightest things there are!

Why? because the immense gravity of a black hole tends to pull matter towards it, in tight orbits, and once close enough, into a whirlpool of sorts that enters into the black hole. Matter including things like stars! so a black hole might not itself produce light but it is surrounded by a bunch of things there are. Saying a black hole is a "light ring with a black inside" would actually be more physically accurate.

In addition, that matter, as it accretes around the black hole, it gets super hot and actually glows. This forms quasars, which are (I'm pretty sure) the most energy-efficient way to turn matter into energy in the universe, and hopefully one day we can control this process artificially with mirrors to extract this energy for human use. Here is what quasars look like:

By ESO/M. Kornmesser - http://www.eso.org/public/images/eso1122a/, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=15700804

So black holes aren't black. Yes, anything within the event horizon (Schwarzschild radius) is black but black holes in general look more like Gargantua in Interstellar than pure black regions of space.

EDIT: Something I forgot to mention but even if black holes don't have gas clouds/matter in their immediate vicinity, you would still definitely "see" them. This is because of gravitational lensing; the gravity of a black hole means that photons travelling from the rest of the universe follow curved paths around them, resulting in a lens-like effect. See here (I didn't make this but it's super cool!) for a very nice visualization. And yes, technically neutron stars also cause gravitational lensing, all things with mass do, but it is the most visible with black holes.

[artbyzigzag]

Meep by ./\/\/\/

Follow me and support my photography.

[dark-rx]

Geyser Season on Mars

This Oct. 29, 2018, image from the HiRISE camera on NASA’s Mars Reconnaissance Orbiter captures geysers of gas and dust that occur in springtime in the South Polar region of Mars. As the Sun rises higher in the sky, the thick coating of carbon dioxide ice that accumulated over the winter begins to warm and then turn to vapor. Sunlight penetrates through the transparent ice and is absorbed at the base of the ice layer. The gas that forms because of the warming escapes through weaknesses in the ice and erupts in the form of geysers.

HiRISE, or the High Resolution Imaging Science Experiment, is a powerful camera that takes pictures covering vast areas of Martian terrain while being able to see features as small as a kitchen table.

Image credit: NASA/JPL-Caltech/University of Arizona