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. It just gets thinner and thinner. In low Earth orbit, where the ISS is orbiting, there is still some atmosphere. It’s very, very thin, but it’s there. At the top of Mount... Continue Reading →

We know gravity keeps the Moon in orbit. Why is there no gravity on the ISS?

This is an image of Newton’s Cannon. Given a high enough elevation, shooting a canon-ball at increasing velocity will cause it to travel further and further until it just goes into orbit, falling around the earth. That is what’s happening inside the ISS. It’s called free-fall - the same as Newton’s canon-ball. The ISS is falling toward... Continue Reading →

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. The answer is “no” because, you see, an orbit in a Lagrange point is inherently unstable and would eventually either fall to Earth or fall to the Sun. According to space.com, “L1,... Continue Reading →

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... Continue Reading →

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... Continue Reading →

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... Continue Reading →

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... Continue Reading →

Create a website or blog at WordPress.com

Up ↑

%d bloggers like this: