An asteroid the size of the Rose Bowl has a slight chance of impacting Earth?

I have heard that an asteroid the size of the Rose Bowl has a slight chance of impacting Earth. Experts say you should not "blow it up" because then we would have many smaller impactors with random trajectories rather than one big one that we could pinpoint with accuracy. But, Wouldn't many of the smaller parts burn up in the atmosphere and do no damage at all?

a la: https://en.wikipedia.org/wiki/Chelyabinsk_meteor#Initial_reports

zuz said:

I have heard that

From whom?

zuz said:

Experts say

Who?

zuz said:

I have heard that an asteroid the size of the Rose Bowl has a slight chance of impacting Earth. Experts say you should not "blow it up" because then we would have many smaller impactors with random trajectories rather than one big one that we could pinpoint with accuracy. But, Wouldn't many of the smaller parts burn up in the atmosphere and do no damage at all?

No matter how it is broken apart, it would represent a huge amount of energy and heat. If a lot of pieces burn up in the atmosphere, it could be like a lot of atom bombs going off.

History has shown that the OP posts and leaves. We may not get any clarification.

This would be roughly a 30 MT impact, depending on the composition, velocity, etc. Enough to wreck your day, but not extinction-level. If it breaks into two pieces, now you have two 15 MT impacts. Better? Worse? That depends on a lot of things.

If you broke it into a billion pieces, the story is different.

Vanadium 50 said:

From whom?

Who?

Neil Degrasse tyson, and if you haven't heard of Apophis by now, I suggest you read a little more astrophysicist news.

Vanadium 50 said:

History has shown that the OP posts and leaves. We may not get any clarification.

This would be roughly a 30 MT impact, depending on the composition, velocity, etc. Enough to wreck your day, but not extinction-level. If it breaks into two pieces, now you have two 15 MT impacts. Better? Worse? That depends on a lot of things.

If you broke it into a billion pieces, the story is different.

What I'm saying is if you nuked the thing, it wouldn't break in two. It would explode into many pieces. Some the size of houses, sure, but many more the size of baseballs and small cars.

zuz said:

Neil Degrasse tyson, and if you haven't heard of Apophis by now, I suggest you read a little more astrophysicist news.

Please do not get defensive when someone asks you for specifics. Many of us (including myself) will read your post who have never heard of Apophis. We should make every effort to be precise and to use valid references.

If I'm wrong, (which I probably am) so be it. It just doesn't make sense to me when we have hundreds of tons of space material falling into our atmosphere every day and it does no harm.

zuz said:

If I'm wrong, (which I probably am) so be it. It just doesn't make sense to me when we have hundreds of tons of space material falling into our atmosphere every day and it does no harm.

Not a good analogy and not a good place to wing it. If you do the math the difference will become clear.

An estimated 3 to 500 tons enters Earth's atmosphere daily. Apophis masses 60 million tons, entering in one moment.

And that's not even counting the velocity.

zuz said:

If I'm wrong, (which I probably am) so be it. It just doesn't make sense to me when we have hundreds of tons of space material falling into our atmosphere every day and it does no harm.

Good point. But it is not the number that counts, it is the energy. The muzzle velocity of a bullet typically ranges between 800 t0 2,000 mph (see this). A typical Earth-crossing asteroid could be traveling at around 50,000 mph (see this). That is their speed after falling toward the Sun to a distance matching the Earth's orbit. Remembering that the energy of an object is proportional to velocity squared, an asteroid of the same mass as a bullet would have between ##62.5^2=3,906## and ##25^2 = 625## times more energy than the bullet. The Apophis asteroid that you referred to is estimated to have a mass of ##6 x 10^{10}## kg (see this). You can estimate the energy of that asteroid, but here is some information. It is in terms of the energy in units of megatons of TNT. 1,200 megatons of TNT. That is about 50 time more powerful than the most powerful nuclear bomb ever developed by the U.S., the B41.
That energy exists and will have a large effect no matter how many pieces an asteroid is broken up into.

zuz said:

I suggest you read a little more astrophysicist news.

Good luck! Toodles!

zuz said:

I suggest you read a little more astrophysicist news.

I went to an astro physics lecture one night. I heard there was going to be a leading expert speaking.

When the lecture started, Neil deGrasse Tyson and Vanadium 50 walked out on stage together.

I got so excited, I grabbed the guy next to me and said "Holy Crap! You know who that is up there!?"

And he shrugged and said "Dunno, but I guess he's a friend of Vanadium 50."

Any impact risk from Apophis in this century has been ruled out. So much for reading news.

If you can break an asteroid into pieces that are ~5 meters or smaller and have some time to spread out then yes, these pieces will burn up harmlessly - the energy gets spread out over such a large area that it's not an issue. For something the size of Apophis this needs around a million pieces, even if all of them magically have the same size. How do you break an asteroid into so many pieces of equal or smaller size in a controlled manner?

This thread's question has been thoroughly answered and the rules of the forum thoroughly explained, so it's now closed.