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Why don’t these “thousands” of satellites fall back to Earth, if the likes of the ISS has to use booster rockets to stay up there? It all depends on how thick the atmosphere is where the satellite is orbiting. The atmosphere doesn’t just “end” at a certain height.
How come an orange inside the ISS just floats in the air, as the Earth’s gravity is too weak to pull it, but the Earth's gravity is strong enough to lock the Moon into an orbit, though it being much farther away?
How come an orange inside the ISS just floats in the air, as the Earth’s gravity is too weak to pull it, but the Earth’s gravity is strong enough to lock the Moon into an orbit, though it being much farther away?
This is an image of Newton’s Canon. Given a high enough elevation, shooting a canon-ball at increasing velocity with go further and further until it just goes into orbit, falling around the earth.
What’s happening inside the ISS is free-fall – the same as Newton’s canon-ball.
The ISS is falling toward the earth at the same speed as the objects and people inside the ISS.
The only reason…
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If an intelligent species preceded us on Earth and wanted to leave a record of themselves in a time capsule, then one of the Lagrange points would be a good place for it. Is anyone looking for one there? Great question! You asked specifically if one of the Lagrange points could be a good place to hide a time capsule from the past.
When in orbit, astronauts experience weightlessness. What is this caused by?
When in orbit, astronauts experience weightlessness. What is this caused by?
Astronauts are not weightless. They experience micro-gravity.
As close to the earth that they are, gravity is a huge factor. You couldn’t, for example, step outside and just float away into space.
The reason it seems to be weightlessness is that the ISS and the astronauts inside are all falling at the same speed. The forward movement causes and angular movement away from the earth and the…
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If you fire a gun vertically from the earth's surface, but there is no friction, would it return to earth?
If you fire a gun vertically from the earth’s surface, but there is no friction, would it return to earth?
Yes it would return to Earth. The escape velocity for Earth is more than 11 km per second or 33 times the speed of sound. This is about 9 or 10 times faster than a rifle bullet.
So even without air friction the bullet’s going to go up, gradually slow down, and fall.
The problem is that without friction it’s going to come down too fast and kill someone at roughly the same speed as when it left the…
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The Little Rocket that Was
The Little Rocket that Was
Let’s revisit Sir Isaac Newton’s cannon.
In the above mentioned article we had placed a level on the cannon and shot the cannonball at 1440 feet per second parallel to the ground until it fell and bounced and rolled and came to a stop.
We didn’t want to shoot it up in the air in a big arc to see how far we could get it to go because we knew if we shot the cannonball up in the air in an arc, it…
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Solution to Joe Drops the Ball
Solution to Joe Drops the Ball
In two previous blog posts about Newton’s Cannon and Joe Drops the Ball I posed the question: If falling objects go faster and faster, why don’t orbiting objects fall out of orbit and crash to the ground?
The question is legitimate and also has a perfectly legitimate explanation.
The rate of a falling object is 32.2 feet per second per second, i.e. it goes faster and faster as it goes down. It ac…
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Joe Drops the Ball
Joe Drops the Ball
Meet Joe. Joe has a ball, and his ball is a great problem for the whole world.
Because of Joe’s ball, the Earth may fall into the sun and the moon may fall from the sky. That’s a big problem for a small ball in Joe’s hand.
Joe tosses the ball
The problem is that Joe drops his ball and then tosses it to the side (see illustration at right).
You see, when Joe drops his ball it acceleratesat a…
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