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Stars Can't Be Seen from Outer Space

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posted on Sep, 11 2016 @ 12:37 AM
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a reply to: choos



relative to the earth, the object is falling towards earth at roughly 8.6m/s/s (about 88% of 9.81m/s/s)
all those numbers you have given are fairly irrelevant unless you want to work out the forward velocity of the object relative to the earth?


What is m/s/s? meters per second squared?
Isn't m/s/s a rate of accelaration (like saying an average car goes from 0 to 60 miles per hour in 10 seconds).
en.wikipedia.org...
I was asking about the actual drop speed, not the rate of acceleration until the actual drop speed is reached.
How do I calculate the actual drop speed in miles per hour?




posted on Sep, 11 2016 @ 03:49 AM
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originally posted by: InachMarbank

What is m/s/s? meters per second squared?
Isn't m/s/s a rate of accelaration (like saying an average car goes from 0 to 60 miles per hour in 10 seconds).
en.wikipedia.org...
I was asking about the actual drop speed, not the rate of acceleration until the actual drop speed is reached.
How do I calculate the actual drop speed in miles per hour?


yes meters per second squared or m/s^2 and it is a measure of acceleration.

i dont think you can get a downward velocity figure from an object in a stable orbit, maybe you can and i dont know it. but velocity will need an instantaneous position first and then how long it has been falling to that point or from that point.

assuming it is in a stable orbit and always at ~430km altitude its downward velocity would most likely be 0m/s, since it only has a forward velocity.

if for some reason the object comes to a sudden stop 430km above the earths surface its downward velocity will be 0 as well as its forward velocity at this instantaneous position, then it will star to accelerate straight down. kind of like dropping a ball from a certain height i guess.



posted on Sep, 11 2016 @ 11:47 AM
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originally posted by: InachMarbank


So since it seems concluded here, anything in the thermosphere would absorb heat, and particles in the thermosphere can heat up to 2500 degrees Celsius, should we consider this?
According to the known melting points of all the 118 elements listed here:
www.lenntech.com...
there are only 6 elements that have a known melting point higher than 2500 degrees celsius, enough to withstand the heat of the thermosphere. These elements, and there melting points in Celsius are:
Molybdenum, 2617
Tantalum, 2996
Osmium, 3045
Rhenium, 3180
Tungsten, 3410
Carbon, 3500
Carbon seems the best choice, but it conducts heat very well, too, so I'm not sure yet if any person could live inside a carbon space ship in the thermosphere without being vaporized. But the carbon itself could probably withstand the heat, right?
Isn't the ISS built from aluminum?
The melting point of aluminum is 660 degrees Celsius, and at 2500 degrees Celsius the aluminum would eventually become vapor wouldn't it?


As you said, the thermosphere can RANGE from 500C to 2500C, it depends on the orbital altitude.

"Temperatures in the upper thermosphere can range from about 500° C (932° F) to 2,000° C (3,632° F) or higher."

The ISS is made out of many different materials and several different alloys of aluminum such as 2219 aluminum alloy for example (that is just an example of one such alloy, and yes I know of its melting point, it was just an example of a material), but also combined with the thermal control system, it radiates the heat out via exchanges:

"Waste heat is removed in two ways, through cold plates and heat exchangers, both of which are cooled by a circulating water loop. Air and water heat exchangers cool and dehumidify the spacecraft's internal atmosphere. High heat generators are attached to custom-built cold plates. Cold water -- circulated by a 17,000-rpm impeller the size of a quarter -- courses through these heat-exchanging devices to cool the equipment.

"The excess heat is removed by this very efficient liquid heat-exchange system," said Ungar. "Then we send the energy to radiators to reject that heat into space."

But water circulated in pipes outside the space station would quickly freeze. To make this fluid-based system work, waste heat is exchanged a second time to another loop containing ammonia in place of water. Ammonia freezes at -107 degrees F (-77 C) at standard atmospheric pressure. The heated ammonia circulates through huge radiators located on the exterior of the Space Station, releasing the heat as infrared radiation and cooling as it flows.

The Station's outstretched radiators are made of honeycomb aluminum panels. There are 14 panels, each measuring 6 by 10 feet (1.8 by 3 meters), for a total of 1680 square feet (156 square meters) of ammonia-tubing-filled heat exchange area. Compare that majestic radiator with the 3-square-foot grid of coils found in typical home air conditioners and you can begin to appreciate the scope and challenge of doing "routine" things in space."

ISS Thermal Control


While that is from 2001, it gives you you an idea.



posted on Sep, 11 2016 @ 12:32 PM
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originally posted by: InachMarbank
So since it seems concluded here, anything in the thermosphere would absorb heat, and particles in the thermosphere can heat up to 2500 degrees Celsius, should we consider this?
According to the known melting points of all the 118 elements listed here:
www.lenntech.com...
there are only 6 elements that have a known melting point higher than 2500 degrees celsius, enough to withstand the heat of the thermosphere. These elements, and there melting points in Celsius are:
Molybdenum, 2617
Tantalum, 2996
Osmium, 3045
Rhenium, 3180
Tungsten, 3410
Carbon, 3500
Carbon seems the best choice, but it conducts heat very well, too, so I'm not sure yet if any person could live inside a carbon space ship in the thermosphere without being vaporized. But the carbon itself could probably withstand the heat, right?
Isn't the ISS built from aluminum?
The melting point of aluminum is 660 degrees Celsius, and at 2500 degrees Celsius the aluminum would eventually become vapor wouldn't it?

Air molecules in thermosphere can get so hot primarily because they are far and few in-between, and thus can attain much greater kinetic energy (which is what creates heat) than atoms and molecules in various materials the ISS is made out of. As has been mentioned, the ISS does get hot from sunlight, and has elaborate cooling systems, but it doesn't get anywhere near as hot as those air molecules. Besides, being so large and having large surface area, the ISS also radiates its heat out into space like all objects in vacuum do.

Even the Moon's surface only gets to 123 C during its 13-day lunar "day".



posted on Sep, 11 2016 @ 03:32 PM
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originally posted by: InachMarbank

Approximately, the Earth and the thermosphere are both said to be 93,000,000 miles from the Sun.

Why would the thermosphere absorb heat to such a greater degree?
And why wouldn't this heat make it to Earth?



Interesting questions. There are a lot of answers, some mysteries, and some learning and unlearning to do, just looking at the way you have been asking in this and other posts.

First and foremost, I get the impression that you, like most people who aren't into physics, are mixing heat and temperature together in your head as being the same thing. Also, you seem to be thinking of solar radiation as all one homogeneous lump, and it isn't. You have to pick these things apart a bit to get a less confusing mental image of what's going on.

So, let's start with temperature and heat. Temperature, or how 'hot' something is, isn't heat. Heat is thermal energy. Hot is how a defined object reacts to the heat it has. So something can be very very hot (high temperature) and have little heat (total thermal energy). A useful way to look at it is a white hot needle and a bath full of cool water. The needle is very hot. But since it's got low mass, the heat is low. If you drop it into the tub, the temperature of the water will change very little. Heat and temperature aren't the same units, since they're not the same thing. In the thermosphere, any one particle is likely to be hauling ass, and thus has a 'high temperature'. But since there are only a very few of them, there's hardly any heat, in terms of total thermal energy per cubic meter of thermosphere.

Next, when you're talking about the temperature of something like a gas, you're also talking about the velocity of the particles at the same time. The faster the particles are moving, the higher the temperature is, because the velocity of the particles in the gas IS the temperature in a very real way. Similarly, the velocity of free electrons is also considered (and stated as) their temperature. In the thermosphere, you get a lot of loose electrons and THEIR RMS speed is considered to be 'the electron temperature'. You couldn't measure it with a thermometer but it's still a temperature, and guys who putz around with this measure their success by how they changed the electron temperature in a region. So, think less of a meat thermometer and more of a speed gun that could detect particle velocities, if you had such a thing. As a sort of mental calibration, assuming you remember CRT televisions and monitors, the electron temperature at the faceplate of the tube is in the hundreds of millions Kelvin. Yet, the total heat is only a few dozen Watts, and the glass and the faceplate easily dissipate it.

One more point, the thermosphere is so low a density as to be a really decent lab vacuum. Most high school labs don't have a pump that can produce as good a vacuum as you have where the ISS orbits. So don't picture it as 'hot air' like coming out of a solder reflow work station or something. It's a good moderately hard vacuum, with the occasional molecule of oxygen, nitrogen, sodium and whatnot tearing around in there.


Given that as a starting point, let's start with 'why does the thermosphere become that hot'.

Well, the Sun puts out a lot of different sorts of radiation. It's not just yellow-white light and a feeling of heat on your skin that you might be thinking of as you step outside at noon. One thing you get quite a lot of is really hard UV and some soft x-rays, the occasional really fast moving particle we call 'solar wind'. These hit the very thin atmo in the thermosphere and are almost totally absorbed there, because they interact strongly with gas atoms. Some of the atoms actually have electrons knocked off, and become ions. The electrons that are knocked loose hoon around by themselves for quite a bit. The ions and electrons form what you've heard of as 'the ionosphere'. Other gas atoms absorb the hard UV photons and instead of losing an electron, they just get a kick in the ass from the momentum and become 'hot', or gain a bit of velocity from the photon, depending on how you want to view it. Both are true. The thermosphere and the ionosphere are the same place. They overlap almost totally. The difference being, the ionosphere has bits knocked off or, conversely, the loose bits (electrons). The thermosphere atoms didn't quite lose one, and the energy went into speeding the gas atom up instead. So one way of looking at the thermosphere is that it's the neutral component of the ionosphere region.



posted on Sep, 11 2016 @ 03:44 PM
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(more long winded explanation)

So, "why is the gas in the thermosphere hot", that's because it happily sucks up the gammas, xrays, and hard UV coming in from space, whether that's from the Sun (mostly) or from a nearby GRB. We occasionally get hit with bursts of gammas from deep space events, and the bigger ones actually increase the thermospheric temperature and enhance the ionosphere by those two means - knocking off electrons or converting the photon momentum to gas velocity.

There are other mechanisms for 'why is this gas so hot' as well. Remember, you have a lot of loose electrons and ionized gas mixed in with your neutral gas, since the thermosphere and ionosphere overlap. So, anything that whups the ionized gas or electrons around will speed that up. And they can collide with neutral particles, and transfer their momentum to the neutral particles THAT way. So anything that heats the ionosphere in a region will heat (eventually) the thermosphere as well. There are a lot of mechanisms for doing this. A big one is magnetospheric oscillation. The magnetic field of the Earth moves around. It sort of 'flutters' in the solar wind, for one. As it moves back and forth, it agitates the ionosphere, and that will heat the thermosphere. You get more or less of that over your location depending on where you are in the day-night cycle. Too, anything that causes geomagnetic disturbances will cause more of this.

So that's mostly 'why is the thermosphere so hot'. What you're seeing is a gas so thin as to be a really decent vacuum, the molecules of which are sometimes ionized and sometimes accelerated by hard UV, x-rays and gammas. Since they absorb the bulk of this type of energy within the ionospheric region, there's none left to work that magic at lower altitudes.

That means that the thermosphere is hot mostly because it's absorbing the entire solar (and extra system) budget of gammas, x-rays and hard UV. All of that energy goes into heating the thermospheric region and/or creating the ionosphere out of the thermosphere. By the time you get to the bottom of the thermosphere, it's all been used up. So there's none left to heat the atmosphere below. Relatively speaking.


edit on 11-9-2016 by Bedlam because: (no reason given)



posted on Sep, 12 2016 @ 04:01 PM
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I wiki’d the following assessments…

All the atmosphere weighs around 56,700,000,000,000 tonnes. Around 75% of that weight is within the altitude of 6.8 miles. More than 98% of the atmosphere is nitrogen (78%) and oxygen (20%), having melting points of -210 and -219 degrees Celsius respectively (seeming to make better coolants than Ammonia, which has a melting point of -78 degrees Celsius)

It seems the greatest rate of atmospheric cooling starts before the greatest mass. The remaining mass would only be around 14,000,000,000,000 tonnes. The greatest cooling starts around 120 miles, and temperatures drop to a bearable range by around 50 miles. Above 120 miles, the temperatures seem to range from around 2000 to 2500 degrees Celsius.

The area where the greatest rate of cooling occurs has been called the ionospheric dynamo region.
There is a lot about magnetism reported for this area of the atmosphere.
Magnetism is probably a different topic, and perhaps we will wind up discussing it here…

I wonder what the weight of the atmosphere is in the ionospheric dynamo region…
If it is only 10% of 14,000,000,000,000, that would be 1,400,000,000,000 tonnes.
I wonder if that weight of nitrogen and oxygen is enough to cool heat blasts of 2000 to 2500 degrees Celsius.

The ISS weighs around 450 tonnes.
How many tonnes of water and ammonia does the ISS have circulating its structure to keep cool?

The assumption in this comment is that heat comes from the Sun, or from heat bursts near the Sun above half of Earth, and is cooled by the atmosphere.

You could also assume heat comes from Earth too, but considering this discussion is about heat in the thermosphere, it seems unlikely, heat coming from Earth could be increased in temperature by the ionosheric dynamo region...



posted on Sep, 12 2016 @ 04:04 PM
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Another piece of information I wiki’d about the thermosphere:

“The air is so rarefied that an individual molecule (of oxygen, for example) travels an average of 1 kilometre (0.62 mi; 3300 ft) between collisions with other molecules.”

Is that enough oxygen to breath with?



posted on Sep, 12 2016 @ 04:10 PM
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Here's one of the sun. Taken in space.



Here's a gallery of Hubble Telescope pictures.

hubblesite.org...

Enjoy



posted on Sep, 12 2016 @ 05:47 PM
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a reply to: grey580

The light from the sun isn't interfering with the light from the stars in that picture...



posted on Sep, 12 2016 @ 06:29 PM
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Considering the spin of the Earth, you might be tempted to think, if you took a commercial flight, that travels at an altitude of around 5 miles, traveling against the earth’s spin, westward, like New York City to San Francisco, you would get there faster, (because the earth would spin beneath you, toward you) than if you took a flight traveling eastward, like San Francisco to New York, (because the earth would spin beneath you, from you)

But it is the opposite that occurs, based on the typical flight times reported:

SF to NYC: 5 hr 15 min
NYC to SF: 6 hr 20 min

The reason for this seems to be found: it is due to wind. There is always more wind resistance flying west, so planes can’t fly as fast.

It seems the wind resistance accounts for all the decrease in time span traveling westward, and the spin of the earth has 0% effect on flight time.

But it seems to also be agreed, the spin of the Earth is the reason for this wind resistance. This seems to make sense, because the wind resistance against flights seems to always push in the same direction.

This seems to me as saying, the air in the atmosphere, at least at an altitude of 5 miles, also spins at the same rate with Earth.

And this seems to me as also saying, a flying airplane (made up its own particles), in addition to traveling at its own speed, also spins with Earth, and in no way escapes the gravitational force of the spin at an altitude of 5 miles, no matter the additional speed it is traveling.

At 210 miles altitude, it has here been stated the gravity force is almost the same as it is on Earth, and I think it was also stated to be around 88% as much.
210 miles altitude is a bit higher than the ionospheric dynamo region of 50 to 120 miles.

Is the spin of Earth caused by gravity, or is the spin of Earth what partially causes gravity?

If gravity is almost the same at 210 miles altitude, is the ISS spun with the Earth, like particles in the atmosphere are at 5 miles altitude?



posted on Sep, 12 2016 @ 09:55 PM
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originally posted by: InachMarbank

This seems to me as saying, the air in the atmosphere, at least at an altitude of 5 miles, also spins at the same rate with Earth.


its the jet stream, and I dont believe it flows at the same rate as the earth its caused by temperature and the coriolis effect, so partially the earths rotation.


And this seems to me as also saying, a flying airplane (made up its own particles), in addition to traveling at its own speed, also spins with Earth, and in no way escapes the gravitational force of the spin at an altitude of 5 miles, no matter the additional speed it is traveling.


in theory if an aircraft could obtain a speed high enough at a 5 mile altitude it could reach a stable 5 mile orbit therefore kind of escaping earths gravity, but that speed would be impossibly fast to maintain and nearly impossible to obtain.


Is the spin of Earth caused by gravity, or is the spin of Earth what partially causes gravity?


mass creates gravity. Anything with mass has gravity, so yes even you but by comparison to other forces your gravitational "force" is basically 0.
if anything, the spin of earth would be creating a sort of "anti-gravity" in that it is trying to throw you into space with centrifugal force but the gravity of earth stops this from happening.


If gravity is almost the same at 210 miles altitude, is the ISS spun with the Earth, like particles in the atmosphere are at 5 miles altitude?


being affected by the earths spin has more to do with friction than gravity.
at 210 miles there is basically no friction, so the earths spin wont affect the ISS in this respect.



posted on Sep, 14 2016 @ 03:30 PM
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a reply to: choos

Comparable figures:
A plane travels east 3000 miles at 600 miles per hour; its flight time is 5 hours.
A plane travels west 3000 miles at 500 miles per hour; its flight time is 6 hours.
The reason the plane flew slower traveling west was greater friction (wind/jet stream).
And I think the greater friction comes from the nitrogen and oxygen (and few other particles in the air) locked in the spin east, with earth, causing greater resistance on the plane, slowing it down.

If the plane was not affected by earth's spin as soon as it took off the ground:
It could fly 500 miles per hour, opposite earth's spin, and travel 3000 miles west in 2 hours
And it could never even travel west, without winding up further east, because the earth would spin faster than it traveled.
Obviously this must be false.
If there is a spin to earth, which I think there is, the plane must be locked in with earth's spin.
And I cannot see any reason to think the plane could break away from being locked in with earth's spin, whether it is traveling 500 or 50,000 miles per hour.

And since being locked in with earth's spin seems to be a function of gravity, I am thinking the plane cannot escape gravity using velocity no matter what.
Perhaps there is another means to escape gravity that involves something different than velocity, but I don't know what that could be.
And, if gravity, effectively, has almost the same force at 210 miles altitude that it does at 5 miles altitude, I don't see how the ISS could defy gravity using only velocity.

www.youtube.com...
edit on 14-9-2016 by InachMarbank because: (no reason given)



posted on Sep, 14 2016 @ 04:33 PM
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originally posted by: InachMarbank
a reply to: choos

And since being locked in with earth's spin seems to be a function of gravity, I am thinking the plane cannot escape gravity using velocity no matter what.


A plane being locked to the Earth's spin is not (directly) a function of gravity. I say "not directly" because gravity is involved, but it is NOT the gravity of the Earth directly acting on the plane that is causing the plane to be relatively locked to the Earth's spin. Rather, it is that the Earth's atmosphere is held down by gravity, and that atmosphere (locked to the Earth by gravity) is also being dragged around with the Earth's spin...

...Therefore, you can basically consider the spinning surface of the Earth and the spinning atmosphere to be one thing -- and the plane flying in that atmosphere is part of that atmosphere. So as the atmosphere is locked down by gravity and move with the earth's spin, things in the atmosphere also move with the earth's spin.

Momentum also plays a part in all of this. A plane on the ground is spinning along with the Earth and thus has momentum, but it holds onto that momentum even when it is in the air. It's like if you jumped up in the air; while you are in the air, you have the momentum that the spinning Earth imparted on you, so you continue to spin with the Earth. If you had no momentum, then the Earth would spin under you at 1000 mph while you were in the air -- but that doesn't happen.


edit on 2016-9-14 by Soylent Green Is People because: (no reason given)



posted on Sep, 14 2016 @ 10:30 PM
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originally posted by: InachMarbank

Comparable figures:
A plane travels east 3000 miles at 600 miles per hour; its flight time is 5 hours.
A plane travels west 3000 miles at 500 miles per hour; its flight time is 6 hours.
The reason the plane flew slower traveling west was greater friction (wind/jet stream).
And I think the greater friction comes from the nitrogen and oxygen (and few other particles in the air) locked in the spin east, with earth, causing greater resistance on the plane, slowing it down.


the jetstream is not precisely locked with earths spin, it is indirectly affected by it but also by temperature.
the jetstream represents a tailwind or a headwind depending on the direction of flight. headwind more friction slower flight, tailwind less friction shorter flight.


If the plane was not affected by earth's spin as soon as it took off the ground:
It could fly 500 miles per hour, opposite earth's spin, and travel 3000 miles west in 2 hours
And it could never even travel west, without winding up further east, because the earth would spin faster than it traveled.
Obviously this must be false.


this is all relative, if its relative to a point on earth, that point on earth can be considered stationary.


If there is a spin to earth, which I think there is, the plane must be locked in with earth's spin.
And I cannot see any reason to think the plane could break away from being locked in with earth's spin, whether it is traveling 500 or 50,000 miles per hour.


the earth is spinning, and the plane while on the ground it is spinning with the earth at the same rate effectively. but relative to that point on earth both are stationary.
once in the air it is indirectly connected to the earths spin since its in the atmosphere but that is only friction related.

but there is no friction at 250 miles. there is basically nothing connecting the earths spin to the anything at altitude of 250miles.


And since being locked in with earth's spin seems to be a function of gravity, I am thinking the plane cannot escape gravity using velocity no matter what.
Perhaps there is another means to escape gravity that involves something different than velocity, but I don't know what that could be.
And, if gravity, effectively, has almost the same force at 210 miles altitude that it does at 5 miles altitude, I don't see how the ISS could defy gravity using only velocity.



the ISS isnt defying gravity at all, it is merely using gravity and velocity to maintain its altitude.
theoretically if friction didnt exist the ISS could maintain a 5mile high altitude orbit.. but in reality that is impossible.
edit on 14-9-2016 by choos because: (no reason given)



posted on Sep, 15 2016 @ 02:42 PM
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a reply to: Soylent Green Is People

We seem to be making a similar point, that the spinning of atmosphere and Earth are 1 thing.

I still wonder... how far up into the atmosphere does this 1 spin extend?

My current assumption (or perhaps bias) is the source of the force for the spin comes from the ionospheric dynamo region (50 to 120 miles altitude) because of the magnetism of the area.

Because the ISS is said to be only about 100 miles or so above the ionospheric dynamo region, even if it is traveling 17,000 miles per hour, I would assume it is still locked in with the spin of the Earth and atmosphere. Therefore, I don't see how, it could be continuously falling, and not hit Earth. If it was continuously moving forward at the same altitude, then I could understand why it wouldn't hit Earth. But that isn't the official explanation. As per Isaac Newton's thought experiment, the ISS is in a constant free fall, but avoids hitting Earth, because it is traveling forward so fast, Earth spins out of the way before the ISS can hit Earth. Again, if the ISS is locked in with the spin of the Earth and atmosphere, I don't see how this is possible.

On a seperate note...

You seem to have differentiated between the gravity of Earth, and another gravity. Is that correct, or am I misreading that?



posted on Sep, 15 2016 @ 02:56 PM
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a reply to: choos



the earth is spinning, and the plane while on the ground it is spinning with the earth at the same rate effectively. but relative to that point on earth both are stationary.
once in the air it is indirectly connected to the earths spin since its in the atmosphere but that is only friction related.


What do you mean, once a plane is in the air it is indirectly connected to Earth's spin?
The earlier point was that the spin of the atmosphere, and the spin of the Earth are 1 thing; and the plane in the atmosphere is locked in with this spin.
Is this your understanding?
Friction affects the speed of the plane, but this doesn't change how the plane is locked in with the spin of Earth and atmosphere, if such spin exists, which I currently think does.



the ISS isnt defying gravity at all, it is merely using gravity and velocity to maintain its altitude.


Here is a quote from the ESA:
"The International Space Station with ESA’s Columbus laboratory flies 400 km high at speeds that defy gravity – literally."
www.esa.int...

I think this response to Soylent Green is People could just be copied in response again... Sorry if redundant.

Even if the ISS is traveling 17,000 miles per hour, I would assume it is still locked in with the spin of the Earth and atmosphere. Therefore, I don't see how, it could be continuously falling, and not hit Earth. If it was continuously moving forward at the same altitude, then I could understand why it wouldn't hit Earth. But that isn't the official explanation. As per Isaac Newton's thought experiment, the ISS is in a constant free fall, but avoids hitting Earth, because it is traveling forward so fast, Earth spins out of the way before the ISS can hit Earth. Again, if the ISS is locked in with the spin of the Earth and atmosphere, I don't see how this is possible.
edit on 15-9-2016 by InachMarbank because: (no reason given)

edit on 15-9-2016 by InachMarbank because: (no reason given)



posted on Sep, 15 2016 @ 03:08 PM
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originally posted by: InachMarbank
a reply to: Soylent Green Is People


Because the ISS is said to be only about 100 miles or so above the ionospheric dynamo region, even if it is traveling 17,000 miles per hour, I would assume it is still locked in with the spin of the Earth and atmosphere. Therefore, I don't see how, it could be continuously falling, and not hit Earth.


There is virtually no atmosphere where the ISS orbits (at 200 to 250 miles up). Granted, there is some atmospheric drag that does, over time, affect the orbital velocity of the ISS, it is generally negligible as it pertains to this "big picture" discussion as to how orbits work.

In short, there is an effect that atmospheric drag has on the ISS that NASA needs to consider, but it is NOWHERE NEAR the same effect that a plane flying through the atmosphere experiences.



As per Isaac Newton's thought experiment, the ISS is in a constant free fall, but avoids hitting Earth, because it is traveling forward so fast, Earth spins out of the way before the ISS can hit Earth. Again, if the ISS is locked in with the spin of the Earth and atmosphere, I don't see how this is possible.

The earth doesn't "spin" pout of the way, but rather the surface curves out of the way.

The Earth, being a sphere, has a curved surface. As an orbiting object is being pulled by gravity back to earth, that lateral motion that the object has allows it to move in a direction generally parallel to the surface as it is also being pulled toward the surface. However, because the surface "curves around and out of the way" (because the Earth is shaped similar to a ball), the surface gets out of the way before the object can impact it....

...Again, look at the "Newton's Cannonball" graphic below. It has nothing to do with the Earth spinning. The Earth could be sitting still (not spinning) in the graphic below and the ability to orbit would be similar:
Image Source

In this example, cannonball "B" goes farther than "A" in part because the Earth's surface is curving out of the way. "B" would not go as far if the cannon was fired on a flat surface rather than a curved one. Cannonball "C" misses the Earth because the Earth curves out of the way before gravity pull "C" to the surface, and once that happens, "C" can theoretically continue orbiting indefinitely.

But all of this has nothing to do with the Earth spinning.


edit on 2016-9-15 by Soylent Green Is People because: (no reason given)



posted on Sep, 15 2016 @ 03:16 PM
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originally posted by: InachMarbank
Even if the ISS is traveling 17,000 miles per hour, I would assume it is still locked in with the spin of the Earth and atmosphere. ... Again, if the ISS is locked in with the spin of the Earth and atmosphere, I don't see how this is possible.


Your assumption is incorrect. The ISS is not "locked in" with the spin of the Earth or its atmosphere. If the atmosphere vanished, and/or the Earth started spinning at half (or twice) its normal speed, the ISS and all of the other satellites would stay in the same orbit they are in now.

The only thing that matters in maintaining Low Earth Orbit is the mass of the Earth and the forward momentum of the spacecraft. That's it. No atmosphere needed (or wanted). No spin required (though it helps with launching).



posted on Sep, 15 2016 @ 09:11 PM
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originally posted by: InachMarbank

What do you mean, once a plane is in the air it is indirectly connected to Earth's spin?
The earlier point was that the spin of the atmosphere, and the spin of the Earth are 1 thing; and the plane in the atmosphere is locked in with this spin.
Is this your understanding?
Friction affects the speed of the plane, but this doesn't change how the plane is locked in with the spin of Earth and atmosphere, if such spin exists, which I currently think does.


the atmosphere and the earths spin isnt one thing. the earth spins, friction and temperature differences causes the jet stream. so indirectly the earth is affecting the plane. when the plane is on the ground then yes the earths spin is directly affecting the plane.

to simplify things i can assume that the atmosphere is locked precisely with the earths spin if it will help with the explaination?




Even if the ISS is traveling 17,000 miles per hour, I would assume it is still locked in with the spin of the Earth and atmosphere. Therefore, I don't see how, it could be continuously falling, and not hit Earth. If it was continuously moving forward at the same altitude, then I could understand why it wouldn't hit Earth. But that isn't the official explanation. As per Isaac Newton's thought experiment, the ISS is in a constant free fall, but avoids hitting Earth, because it is traveling forward so fast, Earth spins out of the way before the ISS can hit Earth. Again, if the ISS is locked in with the spin of the Earth and atmosphere, I don't see how this is possible.


its not that the Earth spins out of the way before the ISS can hit earth, its that the earth is a sphere and curves away.

the ISS that is continually moving forward, the earth being a sphere curves downwards so that for every meter the earth curves away the ISS has moved sufficiently forward enough to also fall the same distance the earth has curved away, therefore always maintaining its altitude.

and in this sense it would look like it is defying gravity but in reality it isnt.



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