The NASA space collision will be streaming starting in the next 45 minutes (6 EST)

z31maniac said:

preach (dudeist priest) said:

In the feed they mention they missed their mark by 15m, not bad for it being 100k km away.

One of you math guys work out that % for the Journalism guy.

That's an error of 0.00000015%

GameboyRMH said:

z31maniac said:

preach (dudeist priest) said:

In the feed they mention they missed their mark by 15m, not bad for it being 100k km away.

One of you math guys work out that % for the Journalism guy.

That's an error of 0.00000015%

That's pretty berkeleying impressive. 

In reply to z31maniac :

It had a built in aiming device so once it was close enough it aimed itself.

On a local gun forum they figured this out:

"So, if (for rounding purposes), we consider a 560 foot diameter target to be ~1/10 of a mile... 0.1 / 7,000,000 = 1.428571428571429e-8. So ~ .0000000143 MOA"

preach (dudeist priest) said:

In the feed they mention they missed their mark by 15m, not bad for it being 100k km away.

So, instead of missing the Earth the meteor will now fall on the GRM headquarters?

Update: Results are in, great success! Over 3x the minimum orbit change to meet the success threshold:

https://www.wired.com/story/sucess-nasa-dart-clocks-dimorphos-asteroid/
 

GameboyRMH said:

Update: Results are in, great success! Over 3x the minimum orbit change to meet the success threshold:

https://www.wired.com/story/sucess-nasa-dart-clocks-dimorphos-asteroid/
 

but did we start an intergallactic war is the question? 

GameboyRMH said:

Update: Results are in, great success! Over 3x the minimum orbit change to meet the success threshold:

https://www.wired.com/story/sucess-nasa-dart-clocks-dimorphos-asteroid/
 

It will be interesting to see the analysis of why it was more than expected -  given energy is always conserved, that would have to mean the weight of the body was quite a bit less than expected.  Which also means it's a whole lot less dense.

The future trips there will be very interesting.

In reply to alfadriver :

That's an interesting problem. How do you determine the mass of a "planet killer" from afar?

In reply to bobzilla :

I'm assuming the size is "known" and the speed/diameter of its orbit dictates the gravitational forces.  I think that gets you to mass, just don't ask me to do the math...

stroker said:

In reply to bobzilla :

I'm assuming the size is "known" and the speed/diameter of its orbit dictates the gravitational forces.  I think that gets you to mass, just don't ask me to do the math...

Yea, that.  The main asteroid can be seen, and it's size is seen.  Then you know there's a body orbiting it- and that makes the bigger asteroid wobble- based on the wobble, you can estimate the mass, as well.

But this gives us a pretty direct measurement of the mass of body 2, since it's change in speed due to a very well known mass with momentum is known.   There's a TON more data gotten from this crash than just the knowledge that we can change the direction of a body in space.  Heck, when they get close to see and inspect the impact crater- that will be very illuminating.

In reply to stroker :

but that would also mean you'd need to know the mass of the object it's orbiting right? 

alfadriver said:

stroker said:

In reply to bobzilla :

I'm assuming the size is "known" and the speed/diameter of its orbit dictates the gravitational forces.  I think that gets you to mass, just don't ask me to do the math...

Yea, that.  The main asteroid can be seen, and it's size is seen.  Then you know there's a body orbiting it- and that makes the bigger asteroid wobble- based on the wobble, you can estimate the mass, as well.

But this gives us a pretty direct measurement of the mass of body 2, since it's change in speed due to a very well known mass with momentum is known.   There's a TON more data gotten from this crash than just the knowledge that we can change the direction of a body in space.  Heck, when they get close to see and inspect the impact crater- that will be very illuminating.

The variable that might be in play is how far off of center of mass we hit, if we imparted a moment that may account for some of the momentum.

tuna55 said:

alfadriver said:

stroker said:

In reply to bobzilla :

I'm assuming the size is "known" and the speed/diameter of its orbit dictates the gravitational forces.  I think that gets you to mass, just don't ask me to do the math...

Yea, that.  The main asteroid can be seen, and it's size is seen.  Then you know there's a body orbiting it- and that makes the bigger asteroid wobble- based on the wobble, you can estimate the mass, as well.

But this gives us a pretty direct measurement of the mass of body 2, since it's change in speed due to a very well known mass with momentum is known.   There's a TON more data gotten from this crash than just the knowledge that we can change the direction of a body in space.  Heck, when they get close to see and inspect the impact crater- that will be very illuminating.

The variable that might be in play is how far off of center of mass we hit, if we imparted a moment that may account for some of the momentum.

I know you're an engineer, but anyone ever tell you that you seem pretty smart? I'm over here thinking a huge team of very smart rocket scientists made big math mistakes, but no, just leverage. 

tuna55 said:

alfadriver said:

stroker said:

In reply to bobzilla :

I'm assuming the size is "known" and the speed/diameter of its orbit dictates the gravitational forces.  I think that gets you to mass, just don't ask me to do the math...

Yea, that.  The main asteroid can be seen, and it's size is seen.  Then you know there's a body orbiting it- and that makes the bigger asteroid wobble- based on the wobble, you can estimate the mass, as well.

But this gives us a pretty direct measurement of the mass of body 2, since it's change in speed due to a very well known mass with momentum is known.   There's a TON more data gotten from this crash than just the knowledge that we can change the direction of a body in space.  Heck, when they get close to see and inspect the impact crater- that will be very illuminating.

The variable that might be in play is how far off of center of mass we hit, if we imparted a moment that may account for some of the momentum.

So the expected new spin of the body is less, then?  With conservation of energy- if the spin increased, that would leave less energy to slow the body down.  But the body slowed down more than expected.  So the spin energy would have had to translated to the velocity.

Very possible, as I have no idea if the spin of the body changed, too.

BBS.com: Nasa's Dart spacecraft 'changed path of asteroid'

At the bottom of the article is a nice diagram of how the Dart hit the astroid and changed its orbit.

barefootcyborg5000 said:

tuna55 said:

alfadriver said:

stroker said:

In reply to bobzilla :

I'm assuming the size is "known" and the speed/diameter of its orbit dictates the gravitational forces.  I think that gets you to mass, just don't ask me to do the math...

Yea, that.  The main asteroid can be seen, and it's size is seen.  Then you know there's a body orbiting it- and that makes the bigger asteroid wobble- based on the wobble, you can estimate the mass, as well.

But this gives us a pretty direct measurement of the mass of body 2, since it's change in speed due to a very well known mass with momentum is known.   There's a TON more data gotten from this crash than just the knowledge that we can change the direction of a body in space.  Heck, when they get close to see and inspect the impact crater- that will be very illuminating.

The variable that might be in play is how far off of center of mass we hit, if we imparted a moment that may account for some of the momentum.

I know you're an engineer, but anyone ever tell you that you seem pretty smart? I'm over here thinking a huge team of very smart rocket scientists made big math mistakes, but no, just leverage. 

Hey thanks dude. It was just a guess, but assuming two rigid bodies colliding in space, that's all that can happen. It either transfers kinetic energy in terms of translation or rotation (or heat, I guess, but it's small). I haven't seen any record of its spin, center of mass, or resulting spin.

alfadriver said:

tuna55 said:

alfadriver said:

stroker said:

In reply to bobzilla :

I'm assuming the size is "known" and the speed/diameter of its orbit dictates the gravitational forces.  I think that gets you to mass, just don't ask me to do the math...

Yea, that.  The main asteroid can be seen, and it's size is seen.  Then you know there's a body orbiting it- and that makes the bigger asteroid wobble- based on the wobble, you can estimate the mass, as well.

But this gives us a pretty direct measurement of the mass of body 2, since it's change in speed due to a very well known mass with momentum is known.   There's a TON more data gotten from this crash than just the knowledge that we can change the direction of a body in space.  Heck, when they get close to see and inspect the impact crater- that will be very illuminating.

The variable that might be in play is how far off of center of mass we hit, if we imparted a moment that may account for some of the momentum.

So the expected new spin of the body is less, then?  With conservation of energy- if the spin increased, that would leave less energy to slow the body down.  But the body slowed down more than expected.  So the spin energy would have had to translated to the velocity.

Very possible, as I have no idea if the spin of the body changed, too.

Yes that's what I would guess. It was spinning some, and now is spinning less. Essentially trading some of its rotational kinetic energy for some translational kinetic energy. Again this is just an educated guess. Nothing much else can happen other than translation or rotation. The only other variable I would imagine is if they assumed some constant for "compression" of the body which was too high. Without pouring over their calcs (which I am sure they aren't sharing) I wouldn't know for sure.

Either way it sure is cool to live through this.

tuna55 said:

 

 

Either way it sure is cool to live through this.

Heck, yea.  

alfadriver said:

tuna55 said:

 

 

Either way it sure is cool to live through this.

Heck, yea.  

another big +1 to that!

ralleah said:

alfadriver said:

tuna55 said:

 

 

Either way it sure is cool to live through this.

Heck, yea.  

another big +1 to that!

I mean, in isolation, yes, but I'm not sure it's worth all the other stuff that's happening at the same time

So, for a bigger object, what would the effect be of parking a nuke in front of the astroid and detonating it some distance away just to nudge it with the shockwave and not try to blow it up?

VolvoHeretic said:

So, for a bigger object, what would the effect be of parking a nuke in front of the astroid and detonating it some distance away just to nudge it with the shockwave and not try to blow it up?

That sounds a whole lot harder and more expensive than just "Throw some mass at it". What benefit are you trying to achieve?

Also, I am not an explosive engineer, but there won't be a "shockwave" as such in space. There will be a bubble of gasses with an explosion, but it won't be anything as potent as a shockwave in an atmosphere I suspect. Also I am not sure if we know how to make a nuclear bomb which will go off in space, since they all (in my very uneducated opinion) rely on conventional explosives to ignite them.

You know what? Surely someone has thought of this.

https://history.nasa.gov/conghand/nuclear.htm

There. It doesn't look like that's going to work.

In reply to tuna55 :

Let's ask Bruce Willis and Steve Buscemi.