– Okay, so the solar system is hurtling through space at around 200km/s and by extension so are the planets. I get that we can launch a rocket and land it on another planet, but does this mean that the rocket would also be travelling at approx 200km/s as well?

Question

And additionally, would it ever be possible to launch something into deep space and get entirely left in the dust by the solar system whizzing by? Completely untethered from its gravity?

In: 9

Answer 1

Speed only has meaning if you’re doing it from a point of reference. We’re all travelling at that 200km/s relative to the center of the galaxy. In our everyday lives we don’t calculate speed from the perspective of the center of the galaxy. Otherwise, you would always be exceeding the speed limit in your car and would probably get jailed for life for driving at 12,000 km/h.

On earth, our point of reference is the biggest thing around. The planet itself. In space that’s no longer the only point of reference to consider. That rocket, from the sun’s frame of reference, is moving at earth’s velocity of roughly 30km/s. It speeds up if it’s going to the outer planets, it’s slowing down if it’s going to the inner planets. Once again, that’s relative to the sun.

As for your second question, shift your frame of reference. The solar system is orbiting the center of the galaxy like earth is orbiting the sun. A spacecraft leaving orbit around the sun would be going into orbit around the galaxy’s center, until you hit escape velocity of the galaxy. Just like how a spacecraft leaving earth’s orbit enters orbit around the sun. Unless you boost its speed to hit the sun’s escape velocity like Voyagers I and II.