New asteroid strike images show impact 'a lot bigger than expected'

Close up pictures showed that it is a lot less homogeneous than they expected, with huge boulders right on the surface as well. That doesn’t match with the measured mass and density since boulders are heavy and dense, but maybe there are more internal voids. But then when they touched it, the nitrogen gas that was supposed to blow some dust and sand into the collection chamber also threw a huge amount of material out and away from the probe. It may even have shattered some of the gravel, meaning that stuff is really more like styrofoam. It may still be silicates, but it is probably foamy. Think of pumice rather than sandstone or granite. Those giant boulders might be more like stage props than actual boulders. It will be very interesting to see what that stuff looks like when they get the samples back.

All those stories of hollowing out an asteroid and turning it into a habitat or generation ship for 50,000 people aren’t looking so prescient. :)

Of course on the other hand it could turn out to just be selection bias: sample return missions are obviously going to pick a low–density asteroid that they hope will at least have some dust they can scoop up, instead of picking a really dense one that might turn out to be too difficult to collect from.

Also, I’m ignoring the dwarf planets that happen to be in the asteroid belt, like Ceres. We can reasonably expect them to have some real rocks.

More seriously though, there is as always math for this. For an object to remain torus shaped it has to resist gravity trying to pull it into a more spherical shape around the centre of mass. More info here if your curious https://astronomy.stackexchange.com/q/2092/501

The short timescale of nuclear war decision-making is chaotic, destabilizing, and has almost led to *accidental* apocalypse several times in the 20th century. Slow, deliberated deterrence could take uncertainty and accident out of the equation.

Wait, seriously? Maybe I should have paid more attention to the relative scale of these things. That makes it sound like the most reasonable expected outcome is total obliteration.

Your toenail is affecting the asteroid's trajectory, by laws of physics. That adds nothing to this conversation.

Just FYI, this should be affected.

https://www.merriam-webster.com/words-at-play/affect-vs-effe...

(Random aside, the sayings gospel Gospel of Thomas is attributed to Didymus Judas Thomas, effectively Twin Judas Twin, obviously such a twin that they named him that twice)

You slam something into it, and that changes the asteroid's momentum because total momentum is conserved in a collision.

If the asteroid stays in one piece, then after impact, it will be going sideways at some particular velocity. If instead some pieces break off and speed off at a greater sideways velocity, then the parts that didn't break off have to be going at a smaller sideways velocity.

In other words, if some debris breaks off, it carries away more than its "fair share" of momentum, and the remaining part gets less momentum.

One of of the big problems with nuking asteroids is, as in this case, if it's a rubble pile then it can be considerably difficult to get enough physical contact with it to even meaningfully effect it.

Hence the reason for DART: we've got an impressive something but the question is did we even successfully deflect the trajectory of the bulk of the material?

Particularly if the big one would miss, but many of the saller ones don't.

The gist was, we've crashed into a single asteroid. There are zero conclusions we can draw from that sample size. So "a lot bigger" just means someone didn't consider the true range of possibilities.