Stars Can't Be Seen from Outer Space

originally posted by: wildespace
a reply to: sadang

The Spain image is 0.5 sec (or 1/2 sec) exposure. eol.jsc.nasa.gov... (The bright light is the overexposed Moon, by the way)

The Italy image was taken at 1/8 sec exposure, so about 4 times longer. eol.jsc.nasa.gov...

I think you meant the Spain pic is 4 times longer than the Italy pic.

Eric Dollard: The Sun Is Not What We Have Been Told (2013)


www.youtube.com...

originally posted by: zagnuzer
Eric Dollard: The Sun Is Not What We Have Been Told (2013)


www.youtube.com...

Anyone can come up with a theory. Lets see this idiot put his hollow sun through the maths wringer. Because if he doesnt show any maths then this is the equivalent of getting your scientific knowledge from the drunk guy in the pub

originally posted by: sadang
a reply to: 3danimator2014
- so which is what according to your pretty basic knowledge? which is long and which is short?
---
- the last image is for sure and artwork - fotoforensics.com...

it makes no difference which is long and which is short. Im not a photographer.but i do understand that you cant have light sources of wildly differing brightness showing in one exposure. This is as basic as photography knowledge can get.

try taking a picture of your light bulb and the sun at the same time. I really cant believe i need to explain this to adults

a reply to: choos

not sure what you are asking but 6 hours of night time mixed in with starting during sunset or finishing with sunrise could give you this effect.

Do you know what the time lapse period of the J.C. Casado pic was?
I had been assuming it was something like dusk to dawn, but I'm not sure of this...

the reason there is no light from stars seen as explained has to do with who is looking. the light from what were is directed by way of a sort of attraction it seems towards the planet so when looked for elsewhere it bends and is not visible.

a reply to: InachMarbank

I'll add my two cents...

As others have mentioned, going by the trails, the exposure time looks to have been about 6 hours (give or take).

However, there is also no reason to believe the entire thing is one single image; it may be made of two or more images stitched together. Therefore, even if the exposure time of the image/images was 6 hours, the north celestial pole part of the picture could have been taken at a different time of day (a different 6-hour span) than the south celestial pole part of the image.

a reply to: wildespace

The Spain image is 0.5 sec (or 1/2 sec) exposure. eol.jsc.nasa.gov... (The bright light is the overexposed Moon, by the way)

The Italy image was taken at 1/8 sec exposure, so about 4 times longer. eol.jsc.nasa.gov...

Thanks for the different Italy pic... I'll go with that one in the future...

There are conflicting statements about what the bright light in the left of the Spain pic is.

Here is an article saying it is a camera flash:

www.dailymail.co.uk...

But the NASA link you provided said it is thought to be the moon.
You can see light on the sea just below it, too, so seems reasonable to think it is the moon.

If it is the moon, would that rule out the fact, that moonlight cancels visibility to stars?

Here is a different link to pictures of star trails, where it says an old moon (I think 1/4 crescent) lit up the sky.
sguisard.astrosurf.com...

To experiment, I took a picture of stars from where I live, between San Francisco and San Jose. There seems to be quite a lot of light interference where I live, but I could at least find 1 visible star.
With my cell phone, I snapped a picture at

1/10th shutter speed:



1/2 shutter speed:



The 1/10th shutter speed was the setting originally set on the phone. This speed captured the star similar to how I would view it with my eye.
The 1/2 shutter speed seemed to grossly exaggerate the star twinkle to something I would not view with my eye.

So, if there are stars visible to a person's eye from inside the ISS, a 1/10th shutter speed seems like it would capture them.

Can anyone explain if the ISS needed to be specially built to withstand temperatures of 2,500 degrees celsius that Wikipedia reports the Thermosphere reaches in the day?

en.wikipedia.org...

a reply to: InachMarbank

While that is a fairly high temperature, there is not much heat involved with the thermosphere. This is because of the extremely low density of the region. The particles that are there are very active, but there are very few of them.

www.ecoca.ro...

originally posted by: InachMarbank
Can anyone explain if the ISS needed to be specially built to withstand temperatures of 2,500 degrees celsius that Wikipedia reports the Thermosphere reaches in the day?

en.wikipedia.org...

That really should be the subject for another thread. However...

This is the difference between temperature and heat.

Temperature is how energetically the atoms or molecules in an area are vibrating.
Heat has to do with how many atoms in that area are vibrating.

A candle in a room has a high temperature (~1,500° F), but doesn't generate enough heat to warm the room.
A large electric heater will be operating at a much lower temperature, but can warm the whole room because it is generating a lot of heat.

The molecules in the thermosphere are vibrating at a high temperature, but there are so few of them (it's effectively a vacuum) that there is very little heat there.

Hope this helps.

originally posted by: InachMarbank
a reply to: wildespace

The Spain image is 0.5 sec (or 1/2 sec) exposure. eol.jsc.nasa.gov... (The bright light is the overexposed Moon, by the way)

The Italy image was taken at 1/8 sec exposure, so about 4 times longer. eol.jsc.nasa.gov...

Thanks for the different Italy pic... I'll go with that one in the future...

There are conflicting statements about what the bright light in the left of the Spain pic is.

Here is an article saying it is a camera flash:

www.dailymail.co.uk...

But the NASA link you provided said it is thought to be the moon.
You can see light on the sea just below it, too, so seems reasonable to think it is the moon.

Daily Mail is tabloid press, and they do get a lot of things wrong. Definitely not the most reliable source of information.

Ask yourself, why would a person taking a long-exposure photo of space and night-time Earth use the flash?...

If it is the moon, would that rule out the fact, that moonlight cancels visibility to stars?

Well, you can still see some stars in that photo. In space, the visibility of stars in a photo is all about the exposure.

P.S. I've checked with Stellarium (a free planetarium software) for the time and position that Spain photo was taken, and can confirm that it's indeed the Moon. The smaller bright blob in the top left corner is Jupiter. I've matched some of the stars, too, and this photo shows some faint stars that wouldn't be visible to the naked eye.

a reply to: Saint Exupery

The molecules in the thermosphere are vibrating at a high temperature, but there are so few of them (it's effectively a vacuum) that there is very little heat there.

That is similar to what Wikipedia said...

"Even though the temperature is so high, one would not feel warm in the thermosphere, because it is so near vacuum that there is not enough contact with the few atoms of gas to transfer much heat. A normal thermometer might be significantly below 0 °C (32 °F), at least at night, because the energy lost by thermal radiation would exceed the energy acquired from the atmospheric gas by direct contact."

A couple questions...

1. Since one could not feel the warmth, but only know that it exists in the few atoms of gas there, how were those atoms measured in temperature? Were astronauts able to obtain a sample of gaseous atoms from the almost vacuous space in the thermosphere and measure the temperature?

2. Wikipedia states at night a thermometer might measure the thermosphere as below freezing. Would a thermometer get a reading close to that during the day?

a reply to: InachMarbank
How hot the ISS gets in the orbit is defined by sunlight. Things in space get hot when under direct sunlight, and cool down when not in direct sunlight (the Moon's surface being a very extreme example). The ISS employs an ammonia cooling system to cool itself down from all that heat.

originally posted by: InachMarbank
1. Since one could not feel the warmth, but only know that it exists in the few atoms of gas there, how were those atoms measured in temperature? Were astronauts able to obtain a sample of gaseous atoms from the almost vacuous space in the thermosphere and measure the temperature?

Iirc, the thermosphere was detected by infrared sensors on high altitude balloons and sounding rockets.

a reply to: wildespace

The ISS employs an ammonia cooling system to cool itself down from all that heat.

I read there was recently (July 2016) an ammonia leak, that astronauts must repair by doing a space walk.
www.nasa.gov...

Do you know if the ISS must come to halt, from traveling approximately 17,000 miles per hour, to allow these repairs to be done?

a reply to: InachMarbank

Do you know if the ISS must come to halt, from traveling approximately 17,000 miles per hour, to allow these repairs to be done?

The ISS cannot come to a halt.

originally posted by: Phage
a reply to: InachMarbank

Do you know if the ISS must come to halt, from traveling approximately 17,000 miles per hour, to allow these repairs to be done?

The ISS cannot come to a halt.

Do you know if the ISS is still traveling near 17,000 miles per hour when the repairs are being done by space walking astronauts?

a reply to: InachMarbank

Yes, it is. Relative to Earth's surface. So are the astronauts.
Is that problematic for you?

originally posted by: InachMarbank

originally posted by: Phage
a reply to: InachMarbank

Do you know if the ISS must come to halt, from traveling approximately 17,000 miles per hour, to allow these repairs to be done?

The ISS cannot come to a halt.

Do you know if the ISS is still traveling near 17,000 miles per hour when the repairs are being done by space walking astronauts?

Yes , both the astronauts and the ISS are moving at about 17,000 mph all the time -- whether they are inside the ISS or outside of it on a spacewalk. That's what makes them "weightless"...

The astronauts are weightless because they are in a free fall along with the ISS. Both the ISS and the astronauts are falling at generally the same speed and in generally the same direction, which is what accounts for them being weightless -- i.e., they fall together in the same direction, giving the astronauts an appearance of weightlessness relative to the ISS.

The direction that they are falling is "sideways", generally parallel to the surface of the earth. That way as they are being pulled down to the Earth by Earth's gravity, their sideways motion is fast enough (17,000 mph in the case of the ISS), that the spherical Earth curves away from them before they have a chance to impact the Earth's surface.

...And that is what defines an orbit. An orbit is a controlled fall as gravity pulls the orbiting object back to earth -- controlled in such a way that the orbiting object never hits the Earth due to the object's very fast sideways velocity.

If the orbiting object came to a halt relative to the Earth (such as the ISS as you suggested), it would fall straight down to Earth's surface due to Earth's gravity pulling it down.