Asteroids hitting gas giants

Disclaimer - this has nothing to do with PA, it's purely about reality.

Moving a gas giant is ludicrously hard. There is nothing accessible to push against. Hell, stars are easier to move than gas giants - at least we have a theory for how that could be done. I have no idea how you'd even begin to go about moving a gas giant short of ultratech hauling neutron stars/singularities around and using gravity to bring the gas giant with you.

If in doubt, magnets. Really big ones.

The candle drive I described in the post right above...
The high end, above the atmosphere, throws superheated hydrogen in space and works like any reaction drive. The low end pushes the other way around, to prevent the candle to plunge in the gas giant. Result, mass (here, superheated hydrogen) is thrown in space in only one direction, and the result is that the gas giant moves in the other direction.

Sure, it's comparatively easier to push stars than planets around, thanks to statites, but it is also ridiculously long, as you need millions of years to acquire any significant speed, and millions more to actually go anywhere.
And pushing stars around wouldn't add much to the gameplay.

I'm pretty sure I mentioned the minor detail of 'there is nothing to push against'. You can't press against the solid core without ultratech because the lower layers of a gas giant's atmosphere are impenetrable to any plausible material, and pressing against the atmosphere is patently ridiculous.

I'm no astrophysicist but I'm not so sure...

Doesn't the gravity holding the gases in to a (rough) sphere kinda behave like the skin of a balloon to hold the gas in, if I push against one area it'd cause all the other areas to bulge out, but the gravity of the planet would resist that expansion?

So the aforementioned 'candle', burning at both ends, may well do the job.

I think if you give enough broccoli to a gas giant it'll move. Certainly works for most gas giants here on earth...

I'm pretty sure the current theory is that there is a solid core to Gas Giants. Unfortunately as far as I know we don't really know for sure. As of yet we lack the technology to get anything down through that soup to actually check that theory. But it does stand to reason that all that gas has to be orbiting around "something".

Also, we have seen asteroid impacts against a gas giant in the past (Shoemaker Levy). Clearly the did hit "something" and presumably that deformed the unseen land below in such a way as to affect the weather patterns on the gas giant for many years since.

I still think the only real issue here is scale. Gas giants are truly enormous. I can't think of any solids in space out there that are actually large enough to really damage one or push them out of orbit. Which is why I said for the purposes of PA, for game simplicity, I'm perfectly okay with just letting gas giants be immune to asteroid strikes.

The solid core is indeed far too deep to push against. But yes, you can push against its atmosphere. That's precisely what the candle does. The subtlety is that, as pointed out above, the atmosphere moved when you push against it can't go much further, as it is still bound by gravity.
Maybe it's easier to see it this way. The candle uses its low engine to stay afloat. It uses its high engine to throw mass into space. The end result, when you look at the planet+candle system, is that you have mass thrown out of it in one direction. With the good action=>reaction formula, you then have the system move the opposite way.
This isn't really harder to get than the statites, which are basically "put a mirror in solar orbit and the star will move".

It hit something indeed, but this something was simply the atmosphere. At those speeds, hitting it won't be that different from hitting rock. Even on Earth, we can see examples of this. Whatever hit us in 1908 near the Tungska (probably a small comet) exploded more violently than most nuclear weapons upon hitting the atmosphere, but never reached the ground.

All that said, you're right about the scale problem. if Earth-like planets are meant to be hard to move...

Source: http://www.schlockmercenary.com/2003-08-03

I particularly like the part where you can possibly turn the gas giant into a star through overheating.

In-air explosives are generally more effective than ground detonating ones, which is why most modern bombs actually explode before impact. If you wait to hit the ground first most of the energy is wasted digging a hole. It may be more impressive to see a crater after an explosion, but the effective blast radius can be significantly larger if the explosive detonates before touching ground.

The Tunguska event also isn't the only time something entering the earth's atmosphere has exploded, just the only one to do any appreciable damage in human memory. There have been several smaller asteroids that usually burn up before touching ground and explode in the upper atmosphere.

The reason comets and asteroids explode is the same reason the SR 71 Blackbird has to refuel after take off. Moving through the air at high speeds causes a lot of friction, and friction causes heat. The SR 71 leaks fuel like a sieve when it's on the ground, it actually relies on the heat generated by air friction to expand the metal components to clamp things closed. For comets and asteroids sometimes they're made of components that explode when put under high temperature, like frozen water for example.

The make up of the gas that surrounds a gas giant is generally far more dense than the earth's atmosphere, which means it generates far more friction when something tries to pass through it. Even Venus, which we certainly don't think of as a gas planet, is covered in a dense and hot atmosphere that reeks havoc with many of the landing attempts we've made. The atmosphere of Jupiter for example is similar to water, so think how much it hurts to do a belly flop... at several hundred thousand miles per hour.

Some to remember is that there is not going to be a clear 'surface' or 'end of atmosphere' on gas giants (i.r.l.). Same with Earth's, as you get higher it gets less dense, and at some arbitrary point we call it 'space' not 'atmosphere', but even in orbit (like the ISS) their are tiny amounts of air. Such that the ISS would fall down due to drag over a few months if we didn't push it back up every so often. Look at http://en.wikipedia.org/wiki/Atmosphere_of_Jupiter#Vertical_structure, you would get zero density at zero pressure, but that never occurs, it just slowly gets really close to zero.

Disclaimer, I don't want these mechanics in game per-say, I am just trying to purvey some cool info

edit: I can totally spell some...

Thanks, I wonder how I missed this one. My google-fu is failing me...

Well, fusion candles would clearly be awesome.
Them having any gameplay usefulness, on the other hand, is another debate.

How about a simple rule "If you cover 20% of the surface area of anything in rockets you can move it". This game does go off of grand scale and resource streams after all. Get enough mass extractors, generators, and engineers with qued up orders and anything should be possible.

Also the gas giants in a video game don't have to be real life scale. Maybe they could just be 2 to 4 times bigger than a normal planet. This will be kind of important when you think that planet size = map size, and we are going to be fighting around gas giants.

bgolus, you might have a pretty good idea already, will gas giants be using a liquid model for the gas (treating the planet more as some type of "special" water only planet, except it isn't water) or will the gas be pure cosmetic (particle engine only, fixed height layer for construction)?

I think Uber maybe have tipped there hand a little with the pledge amount graphics for 1,300,000 reached.

We can clearly see the gas giant hasn't gone pop and while its very possible uber could be trolling, someone did go to the effort of quickly making a different graphic for SOME reason.

Huh, that's strange isn't it. :roll:

I didn't even notice that until now. There's also a faint hint of a circle inside the planet. Maybe gas planets will simply absorb meteors?

My assumption would be that the planet would not crack, but there would probably be a significant "boom"

To answer your question directly, we don't know yet exactly how an asteroid impact will effect a gas giant. However, it's fairly safe to say a pure gas giant isn't going to turn in to a barren lava rock planet just because an asteroid flew threw it.