We still don't know if the Earth is slowly moving towards the sun, away, or not moving at all. Even if it was it would take billions of years to have any effect on us. The moon used to be 4 times closer to the Earth than it now is, but that was roughly 4.5 million years ago. Just think of how amazing that view must have been.

Um.. Yea, The View Would Have Been So Good That We Wouldn't Even Be Able To Exist! HaHaHa!

Take This To Its Logical Conclusion. If The Moon Were Four Times Closer 4.5 Million Years Ago, Then How Long Ago Was It That The Moon Was Actually Touching Us?

avinash habashi at no time in the past it was touching us from the time it formed it was in orbit if it was to close it would have been pulled in and hurt the earth

obviously it wasnt touching us.

im sorry but that is all i got from your post. it is insanely incoherent, and i cant respond to any other point you made because i cant understand what youre saying.

There are a few answers to that..

1) It's not strong enough to pull us in because the Earth has gravity too - enough to keep us here, as gravity exerts a downward force to keep us on the ground.

2) The further you get away from the sun, the less effect the sun has on gravity. In order to stay in orbit, the object requires an orbial velocity. The closer an object is to the sun, the faster it must move to prevent getting sucked in. For example, Mercury's speed is 47.9 km/s, whereas Earth is 29.8 km/s.

3) The idea of gravity stopping on earth, and the effect goes against the laws of gravity. To have no gravity on earth requires no earth. The assumption would be that if an object was moving at no speed (which no object is), then it should get pulled into the sun, provided it didn't get too close to another planet and become captured by it.

Thanks. Very helpful for lightning!

Technically, the Sun is pulling us in.  We don't move closer to the Sun because the motion of the Earth's orbit counteracts the force of the Sun's gravity.  There's nothing to slow the Earth down in space, so our orbit remains stable.

Although gravity can't stop, let's assume, hypothetically, that I invent a machine that stops the gravity of an object.  If we were to stop gravity on the sun, the Earth would fly off into space.  If we stop gravity on Earth (while still allowing the Earth to be affected by other objects), it would stop the interaction between the Sun and Earth, throwing off the Earth's orbit.  It would be hard to predict what would happen after that.  We could fly into the Sun, another planet, or out of the solar system altogether.

Ok. Here's a general knowledge question about something scientific. Why do we measure Radioactive material by it's half life? Why not the whole life of it's decay? or is its radioactive level generally considered to be within safe limits by the time it's reached it's half life?

Whole life wouldn't work as the decay curve of a radioactive material is an exponential decay curve. Essentially the whole life of a piece of radioactive material tends towards infinity.

So we take the half life because its a finite amount of time. Nothing to do with safety.

Yeah, this. After one half-life half of the material has decayed, after two half-lives thre-quarters has decayed, 3 HLs = 7/8 and so on. There's no set time when all of it would have decayed.