This is how NASA would respond to an asteroid impacting Earth

a reply to: Trillium

You would think that a nuclear test - even one in the atmosphere where fireball doesn't touch surface would leave
radioactive traces

For example in 1945 a scientist at KODAK accidently stumbled upon the TRINITY test In New Mexico while investigating
case of X Ray film becoming fogged (exposed)

Determined that the straw board packaging was responsible . Found that the straw board from certain locations
near rivers had been contaminated by radiation which had been rained out

Was able to determine that radioactive material was a beta emitter with half life of around 30 days

The culprit was identified as Cerium 141 - a fission product

US Government made a secret with KODAK to give them warning of tests so could avoid using strawboard from certain locations contaminated by fallout

www.popularmechanics.com...

duplicate port

a reply to: ElGoobero
I would not worry about it. God and even sometimes Crom himselfs looks out for the foolish, and were can you find more of that kind, then on planet earth? Nowhere that's were.

Personally I think there only serving there own selfish self interests, but hey. How else would one explain that we all are still alive in this big cosmos fishbowl?

But if they the NASA, are worried about it. They can always hire Bruce Willis to teach them how its done. And not only that but done in spectacular big bada boom fashion. Because whats the point of saving the planet if you cant do it in a stylish cool fashion.

originally posted by: NicSign
a reply to: OneBigMonkeyToo

rockets working in space is pseudoscience. Rockets don't give the exhaust momentum, pressure gradient force does.

Were you under the impression that "rocket" is the space word for "propeller?"

"Every action has an equal and opposite reaction."

That stream of burning fuel shooting out the back of the rocket is what the rocket "pushes against", its not moving air.

Damn, got to late to the fight....So I guess there was no Sputnik, Soyuz, Gemini or GPS Satellites in space, Sigh!

a reply to: dogstar23

And the guy making the claim about rockets not working figured he would never need to know crap about science. Helps in the real world.

a reply to: roadgravel

Well have you proven an equal and opposite force from gas movement due to pressure gradient force. A simple experiment would help

a reply to: NicSign

The speed of a rocket is limited by the atmosphere on Earth due to friction. A rocket in space pushes against its own exhaust. It travels more efficiently because the rocket has little or no friction to slow it down.

If a rocket fueled with dinitrogen tetroxide and hydrazine attempted to reach the same speed on Earth as it does in space, it would burn up due to friction. That's why some older rockets appear white hot during a launch.

Newton's law still holds: For every action there is an equal and option reaction. In the case of a rocket, the net thrust is given by:

F (sub)n = m v(sub e)

where
F = force (or thrust)
m = propellant flow (the fuel)
e = the effective exhaust velocity.

There are a number of experiments on YouTube demonstrating the third law.

Notice equal and opposite in the diagrams below.

a reply to: Phantom423

Actually this equation is proven to be false. Mass flow rate by itself is not force

www.youtube.com...

a reply to: NicSign

You're misreading the equation. Look at the diagrams. The TOTAL thrust is mass flow rate ( (the propellant) * Velocity plus (+) pressure sub e - pressure sub zero) * A (the area)

The equation does not suggest that the flow rate is a force. It's the end result of the calculation which is equal to the force or thrust. A rate is not a force. It's the volumetric flow rate which passes per unit of time.

You need to pull the equation apart and define the terms and components. It sounds like you're not familiar with physics and fluid dynamics.

a reply to: Phantom423

What are you talking about? Bernoulli’s equation is used to substitute exit velocity out to show that the equation is incorrect.

a reply to: NicSign

You're wrong. Look it up and figure it out. You need to start with some basic physics and work from there. If the third law wasn't valid, rockets would not move in space. Bernoulli has very little to do with the concept. Bernoulli principle is about decreased pressure and decreased energy potential. Your hypothesis suggests that the third law isn't valid because the fuel ejection energy has nothing to push against. Well, I think the diagrams speak for themselves. The combustion energy pushes against its own exhaust. It's pretty straightforward - not much to really understand or think about.

Look, if you don't understand how it works, go to one of the university websites like MIT and access one of the courses in physics. EOM.

a reply to: Phantom423

I’m not saying Newton’s third law is invalid. I am say your applying it wrong. The action/reaction pair is not the rocket and it’s exhaust. You can’t even use simple experiment to prove your claim

a reply to: Phantom423

The peed a rocket can reach is determined by 2 factors, ISP or specific impulse and mass ratio

Specific Impulse if the amount of energy a given propellent gas, the higher the Specific Impulse faster the rocker can travel on given fuel load

By multiplying the ISP by acceleration of gravity ( 32 feet per second, or 9.8 meters second) gives exhaust velocity of the jet

example ISP of 300 seconds 300 x g (32.1 feet/second) = 9630 feet per second exhaust velocity

Second factor is Mass Ratio , ratio of full load weight divided by empty weight

For a rocket to reach its exhaust velocity needs mass ratio of 2.72

To double its exhaust velocity , mass ratio must be squared as carrying weight of extra fuel or 7.3

That is why rockets are staged, the mass ratio of a single stage would need to be tripled or mass ratio of 20 to reach orbital velocity on single stage . Having each stage allows rocker to build velocity in increments

Can we please get back on topic, and not discuss rocket physics here?

This thread is about the threat of asteroid impact and how the humanity would deal with it.

a reply to: wildespace

Not much we can do right now. But for the future, best bet is diversion by some means. Of course rockets won't work in space, but there are some other options. How about hooking a solar sail to it?

Of course, we could take the approach of AGW skeptics and just deal with the consequences when they occur.

a reply to: wildespace

I apologize for the diversion.

a reply to: Zanti Misfit

"Solar winds will be caught by the mylar sails ..."

We see how people act during storm disasters, etc. There isn't going to be notice of an upcoming hit and level of destruction unless someone in the know lets it slip to the public. The chaos will be at a new level.

I suspect it would be claimed a sure miss until it actually hits.

a reply to: roadgravel

Word would get out. There would be too many people who would know about it. Look at Deep Impact (you know, the other ELE event movie with Morgan Freeman as president). Too many people knew and started acting strange and the word got out even though they tried to keep a lid on it for as long as possible.

Neal Stephenson did a better treatment in SevenEves. There was no hiding it, so the government of Earth more or less created an elaborate Ark project that was pretty much a pacifier for the people all along, intended to keep them passive in the face of their extinction. No one really believed it would work, and that the people sent up to it would only die lingering, protracted deaths. But it was intended to keep order on Earth as long as possible.