How Astronomers Missed the Massive Asteroid That Just Whizzed Past Earth

You also can't usefully cool anything to 4K by radiation. The radiative cooling rate goes like T**4, so cooling at 4K is

(4/300)**4 = 3E-8

times as fast as at room temperature. Just the heat from the Moon is enough to dwarf that.

Cheers

Phil Hobbs

It's also a property of fields.

Cheers

Phil Hobbs

-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510

A nuclear blast doesn't do anything worthwhile to the momentum of an asteroid on its own.

The only way it does anything useful is by heating up the surface of the asteroid to the point where the surface boils off.

The stream of vapour away from the asteroid does have momentum, and the pressure of the initial cloud of vapour on the asteroid surface transfers an equal and opposite momentum into the asteroid.

Put the nuclear blast close enough to the asteroid and make it big enough, and the pressure wave propagated into the asteroid could break it up.

Take the nuclear blast away from the asteroid and the inverse square law means that the surface of the asteroid might not even got hot enough to volatilise, and there wouldn't be any change in the momentum - and thus the direction - of the asteroid.

I don't think that NT has actually thought about this all that hard.

In so far as he has thought about it at all.

Do tell. A photon is a feature of an electromagnetic field, and each photon has an energy associated with it's wavelength.

Temperature is all about energy distribution so you needs lots of photons to define a temperature.

A field - as such - is defined by the particles that interact with it, and it does strike me that it would bit tricky to assign a temperature to a static magnetic or electric field.

I do look forward to being corrected.

Actually it is a measure of energy and does not imply the existence of matter. Besides, space contains matter. Even if there is no conventional matter, there is the quantum background "fuzz".

That's good to know, the world has been mistaken to fear the fallout from hydrogen bombs for the last half century, because they don't radiate or contaminate. And all the bother in the early days, treaties to limit testing to underground. Could have just set them all off in the air and avoided all the additional effort.

Wrong, always wrong.

Of course it can work, because if it does turn it into thousands of small pieces, then it's harmless. For proof of that, look at any meteor shower. Almost all burn up, without ever reaching the ground.

You're already doomed by being wrong, always wrong.

th

That's great, but you can choose to not fight a war. Besides, it's like ea rthquakes. The likelihood is small, but the consequences can be huge. Tha t's why we are trying to track the bigger asteroids even though the chances of an impact by one of that size is very, very small. The smaller ones th at we can't track, but are much more likely to impact the planet can still have devastating consequences for the world.

Much of the damage of a nuke is from the vaporizing of matter near the explosion. I wonder how much less the impact of a nuke will be in space where only the material of the bomb itself will impact an asteroid.

Rick C wrote in news: snipped-for-privacy@googlegroups.com:

Planck would differ with you.

Heat... specifically the thing that 'temperature' puts a measure on, is ONLY exibited by atomic / molecular motion.

So matter is required to have heat.

Any you find devoid of matter was 'generated' by matter and is a remnant.

I don't normally bother replying to you as you mostly have no idea of what you are talking about. In this case I can point to the cosmic background r

y involve matter.

Rick C wrote in news: snipped-for-privacy@googlegroups.com:

It involves the moment matter was created throughout the known universe. Duh! It most certainly does (did) involve matter... all of the matter there was and is all at once and we are part of what is left.

Note I did not say you were wrong. Temperature can be measured.

Can you measure it in free space? Empty space?

Does it require something moving to impart change into the transducer you are using to measure it with?

What are you measuring? The air? The surface of a medium? All involve matter and contact with the transducer.

Theorizing ideals? Matter is still there.

If you are measuring the temperature of a photon stream (the solar wind) (source left) with an IR device perpendicular to the flow, what are you measuring and what generated it? Hint: Look left. That star's matter generated that energy.

This is why I usually don't reply to you. When you come up with a wrong id ea, you double down. All your noise aside, the cosmic background radiation is not matter and yet it has a temperature.

arthropods

Better to divert it some other way if you see it in plenty of time. Nuclear explosives are messy.

Although the odd one might still be on a collision course. A bit like slamming the cue ball into the pack the result can be quirky.

I doubt if we have any nuclear launch systems capable of delivering an H-bomb to an incoming asteroid reliably at present.

Maximum destructive force is when the fireball doesn't touch the ground by some slowly varying ratio of its size. A ground burst generates much more fallout and vapourising rocks or water robs the shockwave of power.

In space if you were going to do it to an asteroid you ideally would want to have the thing detonate very close to the target so that it exerts maximum impulsive force. Neutron capture means that the surface facing the blast will be radioactive glass much like Trinitite.

Or for a stoney asteroid probably more like radioactive Obsidian.

Asteroids are mostly loose rubble piles. You're more likely to blast off some superficial stuff while the bulk continues on its original course.

Jeroen Belleman

Rick C wrote in news: snipped-for-privacy@googlegroups.com:

When you spout this stupid horseshit I want to make you eat a 12 ga round. See how that works.

Damn, now I want to "double down" with both barrels. Any way you could stop participating in the retard bandwagon behavior?

When you say "has temperature", that has to be measured and measureable and observable. That means it is moving. Moving means it was emitted. Emitted means that it was emitted from something. No matter remains from that event, except all of us planets, stars, dust and such. Plenty of matter was involved... all of it.

Where does one measure it? What are you measuring?

And what was the source of what you are measuring? Oh... that's right... it is remnant energy produced when all matter we know of was created at the beginning of this thing we all call the universe.

That's a side track over which we can quibble endlessly. As a general rule, it's your leaders that choose in your stead. They tell you to go to war, you go to war. Period. Some random individual may manage to escape, but as a rule, they don't.

Jeroen Belleman

Yes. It does. The cosmic microwave background is from a roughly 4000K hydrogen plasma surface of last scattering at a redshift of about 1100.

that's why you need drillers ;)

Helium boils at The=4.2 K. The cosmic background radiation Tcb is 2.7 K. The problem is finding a large part of the sky with no stars or galaxies. Those heat sources will increase the average space temperature.

The theoretical maximum power that could be removed from one suave meter of the telescope P = c(The^4 - Tcb^) Where c is Stefan