Don't Believe in Black Holes?

[HewenttoJared]

Then what's this?


The first definitive picture of stars orbiting a black hole with a mass equal to millions of stars! How exciting!!!!

http://scienceblogs.com/startswithab...tm_medium=link

[skyrick]

Gasp! You believe in science? Elitist!

[HewenttoJared]

I know, right?

[Kerry]

Becareful what you read - and believe. This quote is from your 'scientist'.

It takes a tremendous amount of energy to get off of the planet Earth. If you were at the surface of the Earth, you'd have to be moving at around 40,000 km/hr (or 25,000 mi/hr) to escape from the Earth's gravity!

Not even a patriot missile, above, has the juice to escape from the Earth.

This photo is from guy with a $1,000 worth of balloons, duct tape and a digital camera.



http://www.robertharrison.org/icarus/wordpress/about/

It all sounds very Heath Robinson but a digital camera, a GPS device, some duct tape and a balloon were all that was needed to take some breathtaking pictures of Earth that had Nasa calling.

Robert Harrison, 38, used a collection of cheap parts costing £500 to create a balloon-mounted camera that can travel up to 21.7 miles (35km) above the surface of the Earth. The result is a series of pictures taken from a height that only a rocket or weather balloon can reach. Mr Harrison, an IT director from Highburton, West Yorkshire, has launched 12 high-altitude balloons (HABs) since 2008.

NASA has ballons that have gone much much higher. None have even come close to 25,000 mph. Check out http://en.wikipedia.org/wiki/Project_Excelsior from the 1950s.

The moral is, if you can't get the well known and basic stuff correct it cast a shadow on what you think you know.

For the record, I believe in black holes.

[Martin]

it takes a tremendous amount of energy to get off of the planet earth. if you were at the surface of the earth, you'd have to be moving at around 40,000 km/hr (or 25,000 mi/hr) to escape from the earth's gravity!

the moral is, if you can't get the well known and basic stuff correct it cast a shadow on what you think you know.

i think you're comparing apples and oranges. a balloon (or a rocket for that matter) has a continuous amount of force being applied in order to counteract earth's gravity. this is not what the individual you quote is talking about. what he's saying is that an object at the earth's surface, with mass approximate to that of a human and with no additional force applied would have to have an initial velocity of 40,000 km/h in order to escape earth's gravity. big difference.

on top of that, i don't think that a balloon on its own could ever escape earth's gravity... but that's a different post. : ) -M

[skyrick]

Becareful what you read - and believe. This quote is from your 'scientist'.

It takes a tremendous amount of energy to get off of the planet Earth. If you were at the surface of the Earth, you'd have to be moving at around 40,000 km/hr (or 25,000 mi/hr) to escape from the Earth's gravity!

Not even a patriot missile, above, has the juice to escape from the Earth.

That is a true statement, proven over and over again by NASA. Escape velocity is approximately 25,000 mph. That balloon will never escape gravity, however high it rises.

[Kerry]

That is a true statement, proven over and over again by NASA. Escape velocity is approximately 25,000 mph. That balloon will never escape gravity, however high it rises.

The X plane didn't travel 25,000 mph and it went to space. The space shuttle tops out at about 17,500 mph. If a Patriot Missile didn't run out of fuel it could escape the Earth as well. The 25,000 figure you guys are talking about would be the speed needed at launch if there was no propulsion system pushing it along (like if it was launched from a sling shot).

[skyrick]

The X plane didn't travel 25,000 mph and it went to space. The space shuttle tops out at about 17,500 mph. If a Patriot Missile didn't run out of fuel it could escape the Earth as well. The 25,000 figure you guys are talking about would be the speed needed at launch if there was no propulsion system pushing it along (like if it was launched from a sling shot).

The X-Plane and space shuttles achieve earth orbit. They don't leave the earth's gravitational influence. If the shuttle and ISS did not fire their boosters every once in a while, they would begin to return to earth. Once again, the quote was about "escape velocity". The physics don't change, however much you may wish them to.

[Kerry]

The X-Plane and space shuttles achieve earth orbit. They don't leave the earth's gravitational influence. If the shuttle and ISS did not fire their boosters every once in a while, they would begin to return to earth. Once again, the quote was about "escape velocity". The physics don't change, however much you may wish them to.

Once again, the 25,000 figure you guys are talking about would be the speed needed at launch if there was no propulsion system pushing it along (like if it was launched from a sling shot). Once in space an astronaught in his space walking suit could send himself into deep space. We send things into deep space all the time and a delta rocket does not go 25,000 mph. When it first takes off it is barely moving.


This is basic physics 101.

[Martin]

it takes a tremendous amount of energy to get off of the planet earth. if you were at the surface of the earth, you'd have to be moving at around 40,000 km/hr (or 25,000 mi/hr) to escape from the earth's gravity!

once again, the 25,000 figure you guys are talking about would be the speed needed at launch if there was no propulsion system pushing it along

so you agree with the scientist you originally quoted. -M

[Swake2]

Once again, the 25,000 figure you guys are talking about would be the speed needed at launch if there was no propulsion system pushing it along (like if it was launched from a sling shot). Once in space an astronaught in his space walking suit could send himself into deep space. We send things into deep space all the time and a delta rocket does not go 25,000 mph. When it first takes off it is barely moving.


This is basic physics 101.

How would you know what's in Physics 101, it's very obvious you never took any class in physics at all.

[Kerry]

I actually spent 2 1/2 years majoring in aerospace engineering. I have had more than my fair share of physics. After Calculus III I just got burned out.

[Swake2]

I actually spent 2 1/2 years majoring in aerospace engineering. I have had more than my fair share of physics. After Calculus III I just got burned out.

You mean Diff EQ, right?

Sure you did.

[PennyQuilts]

Who the hell doesn't believe in black holes?

Most of us don't understand enough about it to have an opinion - certainly not enough to rebut what the scientists tell us. And even the christian fundamentalists don't have any biblical reason to argue against them.

[Kerry]

You mean Diff EQ, right?

Sure you did.

Differential Equations was after Calc III (at least at OU it was).

[jn1780]

Once again, the 25,000 figure you guys are talking about would be the speed needed at launch if there was no propulsion system pushing it along (like if it was launched from a sling shot). Once in space an astronaught in his space walking suit could send himself into deep space. We send things into deep space all the time and a delta rocket does not go 25,000 mph. When it first takes off it is barely moving.


This is basic physics 101.

Define "outer space". A space walking astronaut who pushes off of the shuttle or ISS can only make relatively small changes to their orbit around Earth. To them it would seem like to them that they were in outer space because the vehicle they pushed off is in a "slightly" different orbit relative to them and they would feel truly screwed. Eventually their body would burn up like everything else in low Earth orbit.

Launching a ship from high altitudes would be easier because the atmosphere is less dense and it would take less fuel. However, the ship would still need to get enough velocity to escape Earth's gravity and who knows how many ballons it would take to lift the ship loaded with the necessary fuel. Its take a lot more than a simple push off.

[Swake2]

Differential Equations was after Calc III (at least at OU it was).

I don't buy that you have taken any of these courses anywhere. If you don't understand the difference between a balloon filled with a lighter than air gas rising in the atmosphere to find equilibrium with the air (and air pressure) around it and the force needed to launch an object out of earth orbit you have never taken any physics class.

[Kerry]

so you agree with the scientist you originally quoted. -M

I would agree with the 'some scientist' if he had cited an example of a non-propulsion vehicle, but he didn't - he cited a patriot missile. If the patriot missile doesn't run out of fuel it goes to space and gets nowhere close to 25,000 mph.

Now back to the original post - who doesn't believe in black holes?

[Swake2]

I would agree with the 'some scientist' if he had cited an example of a non-propulsion vehicle, but he didn't - he cited a patriot missile. If the patriot missile doesn't run out of fuel it goes to space and gets nowhere close to 25,000 mph.

Now back to the original post - who doesn't believe in black holes?

Ok Mr Physics, why don't you show us the math on that?

[Kerry]

Ok Mr Physics, why don't you show us the math on that?

LOL - show you the math on what? The space shuttle tops out at about 17,000 mph before it leaves the Earth's atmosphere. How much more proof do you want? If you throw a baseball it has to go 25,000 mph to escape gravity, but if the baseball has its own power it could do it traveling 1 mph so long as it has enough fuel. The only physics involved is the weight and burn time of the fuel.

[skyrick]

LOL - show you the math on what? The space shuttle tops out at about 17,000 mph before it leaves the Earth's atmosphere. How much more proof do you want? If you throw a baseball it has to go 25,000 mph to escape gravity, but if the baseball has its own power it could do it traveling 1 mph so long as it has enough fuel. The only physics involved is the weight and burn time of the fuel.

Once again, the space shuttle leaves the Earth's atmosphere, but not its gravitational influence. Without booster firings at measured intervals it would start to fall back to Earth. I think you are confusing escape velocity with orbital velocity.

[Martin]

i would agree with the 'some scientist' if he had cited an example of a non-propulsion vehicle, but he didn't - he cited a patriot missile.

well... let's review the quote, shall we. first, we have:

if you were at the surface of the earth, you'd have to be moving at around 40,000 km/hr (or 25,000 mi/hr) to escape from the earth's gravity!

it can plainly be seen that the first example is you... a person. any person. this example doesn't include the idea of propulsion at all. the only thing discussed so far is initial velocity. without propulsion, one would have to be moving with an initial velocity of 40,000 km/h in order to escape earth's gravity. you agree with this.

then, we have:

not even a patriot missile, above, has the juice to escape from the earth.

notice the words, "not even?" that should give you a grammatical cue that the author is changing subject. you might try to say, "but it says 'above' in the quote!" in the original article there is a picture of a patriot missile and 'above' refers to that and not the 'above' example of initial velocity. so now we're talking patriot missiles and propulsion. as noted, patriot missiles don't have enough "juice" (propellant) in order to break orbit. there's nothing about having to go a minimum speed. you also agree with this.

in fact, there is nothing in the caption you quoted that you disagree with.

once again, the space shuttle leaves the earth's atmosphere, but not its gravitational influence.

true... but the shuttle could break earth's gravity without going faster than 17,000 mp/h provided it had enough propellant to do so.

-M

[Kerry]

All right - I agree with your summation MMM. Now who didn't believe in black holes again?

[Martin]

now who didn't believe in black holes again?

i'm not sure who, but i suspect he's made of straw. : ) -M

[HewenttoJared]

Becareful what you read - and believe. This quote is from your 'scientist'.



This photo is from guy with a $1,000 worth of balloons, duct tape and a digital camera.



http://www.robertharrison.org/icarus/wordpress/about/



NASA has ballons that have gone much much higher. None have even come close to 25,000 mph. Check out http://en.wikipedia.org/wiki/Project_Excelsior from the 1950s.

The moral is, if you can't get the well known and basic stuff correct it cast a shadow on what you think you know.

For the record, I believe in black holes.

Is this some kind of joke? There is a huge difference between leaving Earth and merely getting high enough to take some pretty pics. The guy was right, and if you can't see why i don't really know what to say.