Posts by HDE 226868
TimB's answer is basically what I would write, except for a very small loophole that I'll include here. Any celestial body does not actually orbit another body, but a point in space called the sys...
I love this one. I really do. Quick Answer: I'd put the date at roughly 2.3 billion years ago, give or take. This is the date of the Great Oxygenation Event. It's when organisms (bacteria) began ...
This cannot happen. Here's why: Conservation of electric charge would be violated: The Earth is made of protons, neutrons, and electrons. Electrons are charge; protons and neutrons contain partic...
Well, it's really, really, really, really unlikely, but I suppose there's a mechanism for it (albeit unlikely). I think you get the picture. Take your planet. Now take a very dense neutron star. P...
I realize that creating worlds with multiple moons and/or suns is risky I think I implied this is one of my answers. I suppose that this statement really comes down to opinion, but there's som...
Well, it might. But only a little, for now. As others have pointed out, we only get a small portion of our energy from solar power. However, the Sun is indirectly related to other methods of produ...
TL,DR: TL,DR: Would humans beings from Earth be seriously injured or killed from the long period variation of the main color a bunch of stars projects on a planet? My TL;DR: Yes. Could such a...
Let's do a calculation or two, shall we? (Note: All those wishing to skip the boring math can just read the lower portion of this answer.) Finding the speed you're going for: $$v=\frac{15 \text { ...
Neil's completely right that the question is a bit confusing. There are two scenarios here: The planet orbits in the same plane as the stars, or it orbits 90 degrees perpendicular to them. There's ...
The hard part here would be that the medium this civilization lives in would be fairly disturbing. Ocean currents can fluctuate easily in certain spots, creating chaotic flows. Maelstroms and other...
One way to achieve this would be to simply change the structure of Earth's magnetic field. At the moment, the field is that of a large magnetic dipole, with the field produced by the motion of flui...
Awesome! I can talk about what I think is one of the coolest inventions of all time: the analog computer. An analog (more properly, a mechanical) computer was actually the world's first "computer"...
My personal favorite is My Solar System, by the University of Colorado-Boulder. You can also access version 2.04 directly here. It's pretty basic, but it has some cool features. You can choose to ...
I don't know how realistic a scenario this is. I would think that if two cores formed in Earth (this could happen in the early solar system, if another moderately-sized protoplanet hit Earth), they...
I'm not going to calculate at what speed the planet would have to move in order for this effect to happen. My guess is that it would have to go pretty darn fast for there to be a substantial differ...
Mercury vs. the Sun Mass: Mercury - $3.3022×10^{23} \text{ kg}$; Sun - $1.98855×10^{30} \text{ kg}$. Mercury clearly won't so much as jostle the Sun. There should be no major changes in the Sun...
I think another defining factor is how large the ship is to begin with. If you have more components (more engines, wings (for a spaceplane), landing gear, etc.), there's a greater chance that somet...
Awesome question. I love this kind of thing. Wikipedia of course has a a page on near-Earth supernovae, and the first body paragraph briefly examines the effects of life on Earth. The only really ...
You could always simply lie down. Jokes aside, the answer is that there would be quite a few issues. Your spine would not be used to being so compressed. This is a problem with astronauts returnin...
A few easy steps to destroying Earth: Get hold of a fairly massive celestial body. It could be a star, a rogue planet (as PipperChip mentioned), or something completely different. Put it in a pos...
This is a really cool question, and I think I can (partially) answer it. Here goes. If two portals are placed a different heights, someone approaching the higher portal should perceive a gravit...
As has been discussed already, different objects would fall at different speeds. Why? Wikipedia led me to an interesting derivation. Consider Newton's second law: $$F=m_ia$$ Now consider his law o...
I'm going to give you a cautious "yes". The reason I'm being cautious is that it depends partly on a hypothesis that is, and has always been, controversial. If it's correct, then absolutely, this s...
Secure $850 quadrillion, preferably in cash. Figure out a way to get around one or two famous and fairly successful treaties. Build a Death Star. Modify the Death Star so it won't blow up the enti...
Here's a quick guide to changing the orbit of an asteroid: Figure out where it is. This is the crucial bit. You need to know its position, mass, velocity, orbit, size, density, and composition, a...
