View Full Version : I Wanna move Mars and get away with it

Bearded One
2010-Apr-01, 01:41 AM
How far can I move it?

Say I have what to us are magical capabilities. I can move Mars, in an instant. I am limited in that I can only move it along its orbit. I can move it forward or backwards.

How much can I move it before astronomers on Earth figure out that something is up?

Are little jumps better than big jumps if I wanna stay discreet as long as possible?

I'm curious...

2010-Apr-01, 02:02 AM
The first giveaway would be anomalous Doppler shifts from probes around and on Mars, which would probably be detectable with a move of only a few kilometers, perhaps even less. Deviations from the ephemeris (nowadays, calculable many years in advance) would also become apparent given a large enough change or a long enough time.

Bearded One
2010-Apr-01, 02:07 AM
That would probably be the first indication. What about if the probes and moons were shifted as well? How well do we track these things and compare trajectory against projections? When one misses which gets corrected?

ETA: My first thought was a move of as little as 10 centimeters. Seriously, how much can I get away with?

ETA2: What's the "noise" level in all of this.

2010-Apr-01, 02:42 AM
If one assumes a movement equivalent to one arc second would be detectable by earth-based telescopic tracking systems and if one assumes an AVERAGE distance to Mars of about 78,000,000 km, then a movement of 378 km would be noticed. But the distance between Mars and Earth varies greatly since Mars' orbit is much more eccentric than Earth's.