Lets talk Satellites..

Ram and Sonu are discussing a very complex topic. Here is what they are speaking about...

Ram: You know moon is earth's natural Satellite dont you?

Sonu: What is a Satellite?

Ram: Anything that orbits a planet is a satellite of the planet. Some may be natural and some may be artificial.

Sonu: Artificial? Like all the ISS (International Space Station)?

Ram: Yes, we have many artificial satellites orbiting the earth. This is how our GPS works, we can predict weather, get imagery for Google Earth etc.

Now see this picture I picked from internet... We have satellites in low earth orbit, mid earth orbit or high earth orbit. The longer the orbital distance between earth and the satellite, it takes longer for the full revolution around the earth by Satellite.

Sonu: Okay.. Let me give an Example: Moon takes 28 days to revolve around the earth isnt it. But ISS will be much much more faster. Just a few minutes or hours isn't it?

Ram: Correct. It takes just 90 minutes for ISS to orbit the earth. Also remember Elon Musk SpaceX Starlink internet satellites?

Sonu: Oh yes, your friend Akshara from Bangalore posted pictures of the night sky where she saw many of these Starlink Satellites..

Ram: Yes Elon Musk wants to launch satellite constellations in low earth orbit to provide low cost broadband internet service to us. This way all remote areas will have internet.

Sonu: Idea is good. But when we see the night sky, wont we see thousands of light spots instead of real stars? And what about space debris in sky?

Ram: True. Its sad but all progress comes with some big impact to environment. But let us come back to our talk on the moon.

Sonu: Yes tell me..

Ram: Do you know Moon is drifting away from earth by 3.9 cm every year?

Sonu: What! What it means?

Ram: I will tell you tomorrow :) Keep thinking what it means... And if you know then tell me.