# Tag Info

3

The picture of a black hole being like a huge vacuum is pretty misleading, not to say wrong. The gravitational field around the black hole is exactly the same as around any other object of the same mass. Like any other object, it's perfectly possible to orbit a black hole, just like we orbit the Sun and don't fall in. In fact, if you were to magically ...

0

You've the answer in your statement: ...black holes are giant vacuums that will absorb/consume the area around it. The key is that the area around it is a few times the event horizon of the black hole and we are very far from the event horizon of the supermassive black hole at the center of the Milky Way. The event horizon for Sag A* (the name of the ...

6

Here is the proof: Please refer to the wikipedia page on eccentric anomaly for a diagram and a couple of intermediate formulae. For an ellipse with the usual formula $x^2/a^2 + y^2/b^2=1$, it is the case that $\sin E = y/b$, and also by studying the figure on the wiki page you can see that $\sin (\pi-\nu) = \sin \nu = y/r$. Thus the two results you wish to ...

3

How long time does it take before three planets achieve the same relative position? The answer is never, except for the case when their orbital periods can be expressed with low integers, like the 4:2:1 resonance of Io, Europa and Ganymede However, what you are asking about is when they are going to be in almost the same position again, a quazi-period. To ...

-1

To understand this, you have to understand how the spin affects the gravity. The spin creates a sling shot effect of pushing an object in the direction of the spin. With that in mind, in a retrograde orbit, there are two forces pushing in opposite directions keeping an object in a purgatory state like. Essentially it's like a game of tug of war between the ...

5

Plenty of others made it clear that babies aren't made out of matter from somewhere else. But if the earth's mass were to increase ten percent by magic, its orbit would not change. Its momentum—its tendency to fly off into space in a straight line—would increase by ten percent, and the counteracting force of the sun's gravity would increase by ten percent. ...

8

As others have said, the mass of the Earth doesn't go up because we are eating food produced on Earth. Suppose we somehow were importing really large amounts of extra-terrestrial food, now what happens? We roast. Food contains a fair amount of carbon. Carbon from extra-terrestrial food is just as much a greenhouse problem as burning fossil fuels. ...

19

Mass is conserved (up to whatever small contribution nuclear decay has to the overall loss of mass). All biological matter is just created from materials from the environment (we do eat, right?). With exception of an occasional space probe, shooting stars and solar wind effects, the earth can be considered a closed system in terms of matter exchange. ...

93

Life forms are made up from materials already present in Earth. Thus, increasing population would not alter the overall mass of the planet, and can't impact its orbit.

3

If at any time the speed of the planet in the reference frame of the star exceeds the escape velocity $\sqrt{2GM_\star/r}$, where $M_\star$ is the mass of the star and $r$ is the distance from the star to the planet, it will escape in a hyperbolic trajectory (or straight line if $M_\star\rightarrow0$). As noted in the other answers, the result of the ...

4

The scenario you suggest is of course hypothetical, but in all cases you must conserve angular momentum and mass/energy. So for example: If you have a way of removing mass from a star in such a way that the mass disappears outside the orbit of the planets (in astrophysics this is accomplished simply by mass loss - either the star has a wind that expels mass ...

1

Your final question very much correlates with a famous thought experiment.If the Sun was suddenly removed the planet s will still continue to stay in orbit. For 8 minutes and 20 seconds. This is because the speed of the space time fabric or simply putting gravity travels at the speed of light. That is, the earth will be devoid of sunlight and will move ...

-2

A coarse correction would have to be made because of the difference in the curvature of space in that section of space when a planet is deleted. The sun holds the planets in orbit and they would fly away as if the string to a tether ball was cut to all the planets.

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