tereseus1 saidi find this to be soo cool...heres a map of how the planets align. Now im sorta wondering what could have collide with Jupiter...could it have been a planet since they said the impact was as big as earth....
Aligned, to-scale, false-distance models of the solar system are probably one of the most misleading depictions of the solar system ever.
The distances between the planets are so vast, that collisions like this is really quite rarely observed. It makes you realize that other objects are constantly flying about in space, and it's really not as empty as we think it is. But certainly not as dense as that picture makes it look like either.
And no, highly unlikely that it was some yet to be discovered planet. The solar system is already a little stable. And any planets of such an eccentric orbit that it would lead it to collide with Jupiter would either be actually extrasolar travelers (planetars) or one of the fabled 'dark matter' objects which do not reflect nor emit detectable radiation, making them virtually invisible in space except for their gravitational influence. Although it's more likely that if it was, it's one of the denizens of the outer solar system. And the bodies in those regions don't quite live up to the designation of 'planet'. They harbor dwarf planets like Pluto, and even those are far smaller than even our own Moon. If they did exist (even though full-sky mapping in infrared and stuff makes it highly unlikely that a larger object than Pluto is still hiding somewhere nearby), they'd either have stabilized by now into an orbit, or would probably have been captured, kicked off, or swallowed by the gas giants a long time ago. And even if one elusive dwarf planet escaped and was only captured now, they'd score a bigger 'scar' than the one observed.
Just beyond the solar system are concentrations of dust and asteroids and minor planets (plutoids like Eris which is the only other solar body larger than Pluto after the eight planets, etc.) and whatnot. Theorized to have been formed from the massive billiard game right after the solar disc started to cool down and form into solid objects. The Kuiper belt, the scattered disc, and much much farther out, the Oort cloud. And a lot of the inner system comets and 'asteroid moons' are theorized to have come from there (particularly the scattered disc region). 'Captured' while in transit. Especially by the gas giants, whose larger gravity wells acts like a net for passing objects (inner system comets seem to have originated from their orbital paths being... bumped. Near misses actually, which acted like slingshots). The gas giants actually help protect the inner planets from such impacts, because they pretty much trap everything near their massive gravity wells.
Also the effects of the impact itself is far larger than the actual object. It explodes like a bomb. Think of rail guns, which use non-explosive ammunition but can explode on impact in a similar or a greater way than explosive ammunition simply because of the speed of impact - metal rail gun bullets will even ignite because of air friction much like meteors/spacecraft on reentry into the atmosphere. Heck, even micrometeoroids pose a significant risk to spacecraft and astronauts. They can puncture a space suit like bullets. So an earth-sized explosion would be from a much smaller body. Not to mention that Jupiter itself is more or less almost wholly gaseous, so the perceived crater would be larger than it would have been if it had hit a rocky planet. Much like how it makes a bigger 'crater' if you drop a rock on water than on sand.
So no. Much more likely to be your everyday asteroid/comet like Shoemaker-Levy.Here's a better 'map'
. If the sun was this big:
Try and see if you can actually find the planets.
. It's correctly scaled, distances and sizes. And the site is probably one of the widest webpages in existence.http://www.phrenopolis.com/perspective/solarsystem/
P.S. Planetary 'alignment' is itself quite impossible. Since although most of the planets are in almost the same plane of the solar disc when it was formed, they still aren't on the same plane. Not to mention Pluto. The other definition of a full planetary alignment which is when all planets are in a straight line from the sun (though not in the same plane), is also quite unlikely. Possible but very very very improbable.