Stars Can't Be Seen from Outer Space

a reply to: Soylent Green Is People

Yeah sure its about the curve, not the spin.

I keep thinking about the spin because I keep thinking the spin has partially to do with gravity (is a half of it)...

But maybe I'm trying to jump ahead too much... Anyway...

210 miles is not really a vacuum is it? There is still gravity, right?

And, as evidenced by Felix Baumgartner, with less particles at an altitude of 20+ miles, the push down of gravity became stronger.

Wouldn't this push down from gravity eventually overcome the momentum from the, basically, one time, or upfront only, thrust of a rocket?

I don't see how a rocket could maintain infinite momentum, without using its engine, in the absence of particles, but with the full, or almost full, presence of gravity.

Isn't gravity a permanent force and the rocket only a temporary force?

originally posted by: InachMarbank

210 miles is not really a vacuum is it? There is still gravity, right?

gravity extends far, very far.

And, as evidenced by Felix Baumgartner, with less particles at an altitude of 20+ miles, the push down of gravity became stronger.

Wouldn't this push down from gravity eventually overcome the momentum from the, basically, one time, or upfront only, thrust of a rocket?

gravity gets less the further from the surface you are, so gravity at 5 miles is higher than graivty at 20+miles.

Felix didnt demonstrate a higher gravity, he would have demonstrated the effects of friction and lack thereof.
ie. 20+ miles there would be fewer particles than at 5 miles so he would have less friction and would fall faster (reach a higher terminal velocity) even though at 20+ miles there is less gravity.

I don't see how a rocket could maintain infinite momentum, without using its engine, in the absence of particles, but with the full, or almost full, presence of gravity.

at the altitude the ISS orbits there is basically no friction, therefore basically nothing to slow the velocity of the rocket when it was put into that orbit.
think of newtons first law.

the ISS is put into motion by the rocket, the rocket switches off, there is no friction to slow the ISS down, so by newtons first law it will maintain that initial velocity since there is nothing to slow it down.

Isn't gravity a permanent force and the rocket only a temporary force?

yes.

a reply to: choos

Newton's first law says an object in motion will stay in motion unless acted upon by an unbalanced force.

So it is said there is a forward acceleration to 17000 mph, then the engines are shut off.

Now, let's say there is also a straight down force that will cause acceleration to 1000 mph (gravity)...

Isn't this an unbalanced force upon the forward momentum (or inertia) of 17000 miles per hour.

And if the forward force is shut off, but the downward force is never shut off, wouldn't the downward force slow down the forward momentum?

originally posted by: InachMarbank

Now, let's say there is also a straight down force that will cause acceleration to 1000 mph (gravity)...

Isn't this an unbalanced force upon the forward momentum (or inertia) of 17000 miles per hour.

there will be one resultant for and that is the acceleration downwards.
but there is no force to stop or slow the forward momentum.

assume its over a flat surface that goes on into infinity, what you will see after observing the object for one hour is that from its first point you began watching the object has moved 17000miles horizontally and lost a whole lot of height. dont have a calculator so i cant be bothered working out exactly how much it has fallen.

but since this is assumed to be over a flat surface that stretches out horizontally to infinity it will eventually hit the ground. but will always maintain its forward velocity (atleast until impact)

And if the forward force is shut off, but the downward force is never shut off, wouldn't the downward force slow down the forward momentum?

once the forward force is shut off, it will maintain its velocity, ie. since there is no friction there is no forward force and no stopping force so net force is 0.

the down ward force acts independantly of the horizontal force.

basically in order to stop the forward/horizontal velocity you need a force acting in the opposite direction (which is what friction does)

a reply to: choos
- are you sure? how deep understanding! exactly as for light and its creation.
- the thermosphere has a specific matter density and there are gravitational and magnetic fields forces influences and also a influence from solar wind, which all these act over the ISS and make it loose about 5cm/s in velocity and about 100m/day.
- now how is with "there is no force to stop or slow the forward momentum."? in every corner of this universe there are forces that act stronger or lesser on matter or on other fields if you want to consider the wave duality of particles.
- and finally what all these have to do with the main theme of this topic?

a reply to: choos

Perhaps you have almost no push back from particles at a 180 degree angle (reverse force), since there are so few particles.

But you do have push down at a 90 degree angle (downward force) don't you?

And again, if the forward force is shut off, wouldn't the perpetual downward force eventually overcome the forward momentum?

Twice, it seems you have made comments I can't wrap my head around.

Earlier you seemed to suggest particles in Earth's atmosphere are independent (not part) of Earth's spin. But a round trip flight from San Francisco to New York conflicts with this point.

And recently you seemed to suggest an object's temporary forward momentum cannot be stopped or slowed by a permanent downward force.

originally posted by: InachMarbank

But you do have push down at a 90 degree angle (downward force) don't you?

And again, if the forward force is shut off, wouldn't the perpetual downward force eventually overcome the forward momentum?

not really because they are always at right angles.

Earlier you seemed to suggest particles in Earth's atmosphere are independent (not part) of Earth's spin. But a round trip flight from San Francisco to New York conflicts with this point.

the jet stream is affected by the earths spin, but this is more due to friction, temperature plays a larger role.

And recently you seemed to suggest an object's temporary forward momentum cannot be stopped or slowed by a permanent downward force.

the forward momentum needs a force that is in the opposite direction for it to slow down, since this forward momentum is always parralel with the earths surface it will always be at right angles with the downward pull of gravity.

gravity cannot slow the forward mometum of the object. only friction can (of which there is basically none) or using the thrusters.

a reply to: choos

How does temperature play a larger role in regards to the wind/jet stream that seems to always move eastward?

I read the average person uses 550 liters of oxygen per day. I also read that oxygen particles could be mile(s) apart in the thermosphere. The videos of astronauts inside the ISS make it seem the astronauts are breathing very comfortably. Are there oxygen support systems on the ISS?

Can anyone else confirm it true, in a vacuum, gravity cannot slow forward momentum?

a reply to: InachMarbank

Are there oxygen support systems on the ISS?

Yup.
I had my suspicions, now confirmed. Troll.

originally posted by: InachMarbank

How does temperature play a larger role in regards to the wind/jet stream that seems to always move eastward?

because temperature differences is the primary drive for movement of air. although i would probably be wrong saying it plays a larger role than the rotation of earth as im not sure, its still most likely the major component as you do get easterly jets.

a reply to: Phage

Are you saying there are oxygen support systems on the ISS?

originally posted by: InachMarbank
a reply to: Phage

Are you saying there are oxygen support systems on the ISS?

Well done, mate, you can pat yourself on the back. At least it's been somewhat enterntaining, and we do enjoy doing some research when answering the questions (even if they are troll questions), and sometimes learn something new for ourselves.

a reply to: wildespace

I'm not a troll. I'm here to learn... just like you are, right?

I miss GaryN. Don't you?

Hasn't been a thread or post about "no stars in space" in a long while.

originally posted by: grey580
Here's one of the sun. Taken in space.

If thats what the sun looks like in space. Why does the Apollo 12 sun look like this ? Why is it so big ?

a reply to: Ove38

different :

lense properties

focal length

arpeture

shutter speed

film stock // digital sensor properties

I want to see where is he going to take this .

a reply to: 23432

i know where he is going : round in circles

originally posted by: ignorant_ape
a reply to: Ove38

different :

lense properties

focal length

arpeture

shutter speed

film stock // digital sensor properties

So, it's the camera that creates the fake Apollo sun ? in reality it is as small as the Space Station (ISS) sun ?

originally posted by: Ove38

originally posted by: grey580
Here's one of the sun. Taken in space.

If thats what the sun looks like in space. Why does the Apollo 12 sun look like this ? Why is it so big ?

Exposure and focal length.