Space question for the scientists out there

[mdstuart]

Are the voyager craft really now slowing down showing that there is more than gravity affecting them?

Also why do the asteroids not all clump together, again showing there is more than gravity affecting their motion....

As I understand it magnetics and the solar wind might be the answer?

Mark

[Capricorn]

I believe that the answer to the second question is that the gravity of Jupiter is the reason that the asteroid do not clump together. Being so big the gravity from Jupiter prevents it. As I recall the position of the asteroids is "correct" for a planet - I forget the rule that appears to indicate a planets radius from the sun.

As to Voyager slowing down. I would guess at this stage they are not being propelled and there is this gravity area called the solar system, (sun and a few planets), that will be exerting a gravitational effect on them.

Magnetics and solar wind? Magnetism must be very weak and the solar wind would push away from the sun not drag things back.

[The Warthog]

The rule is, you double the distance from a planet to the sun to get the distance to the next planet. The distances from the sun to the planets is, in AU, .39, .72, 1, 1.52, 5.2, 9.54, 19.18, and 30.06. The rule works, roughly, except for Earth and Neptune, and there is a gap between Mars and Jupiter. It is thought that Jupiter's gravity prevented the formation of a planet in the asteroid belt, which would fit into the gap. There isn't enough material in the asteroid belt to make a decent sized planet. Most of it has been expelled by Jupiter for fighting in the school yard.

As a rule, it's rough, but it is handy for remembering the approximate distances to the planets.

Years ago, I read a lame science fiction novel which put a lot of strain on a phrase (by Kepler?) Inter Martem et Iovem planetam interposui - I would put a planet between Mars and Jupiter. I have remembered the rule ever since.

Doing this little exercise caused me to realize that when I have been looking at Neptune, I am looking at light that has taken 8½ hours to get from the Sun to Neptune and back to Earth. Amazing!

[The Warthog]

So, the proportionate distance from one planet to another, not counting Earth and Neptune, is Mercury to Venus – 1.8, Venus to Mars – 2.1, Mars to asteroids – 1.8, asteroids to Jupiter – 1.9, Jpiter to Saturn – 1.8, Saturn to Uranus – 2.0. This gives an average separation of 1.9 which means the rule is pretty close. Interesting!

[Ben Ritchie]

Are the voyager craft really now slowing down showing that there is more than gravity affecting them?

The Pioneer spacecraft are slowing down more than expected - Pioneer anomaly - Wikipedia, the free encyclopedia

Possible reasons - Pioneer anomaly - Wikipedia, the free encyclopedia