APOD: Endeavour's Starry Night (2011 Jun 02)

[APOD Robot]

Endeavour's Starry Night

Explanation: This luminous night view of the space shuttle orbiter Endeavour, docked with the International Space Station for a final time, was captured on May 28. Orbiting 350 kilometers above planet Earth, Endeavour's payload bay is lit up as it hurtles through Earth's shadow at 17,000 miles per hour. At the top of the frame, the jointed appendages of the station's robotic manipulator arm Dextre appear in silhouette. Motion during the long exposure produced streaks in the starry background and the city lights on the darkened planet below. Completing a 16 day mission, Endeavour made a it's final landing at Kennedy Space Center in the dark, early morning hours of June 1.

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[Guest]

Nope, not 27,000 mph. That's higher than escape velocity. 17,000 mph would be closer.

[skiptic]

27,000 kph

[Beyond]

Star light,star bright, i wish upon a star tonight. I wish i may,i wish i might, but alas; i'm not equipped for flight.

[Giordano Bruno]

We do see stars ...
Remember Apollo 11 Post flight Press Conference : " We have not seen any star ... "
Never too late to replace an old lie belief by truth and evidence
Let's have together a good day

[nstahl]

I take it the 27,000 was changed to 17,000 here in the Discussion; it's still 27,000 mph on the APOD page.

[neufer]

We do see stars ...
Remember Apollo 11 Post flight Press Conference : " We have not seen any star ... "
Never too late to replace an old lie belief by truth and evidence
Let's have together a good day

Apollo crews never stuck around until nighttime (nor when the earth wasn't mostly full).

The stationary stars and shuttle make a good companion piece with:
http://apod.nasa.gov/apod/ap110601.html

[Ann]

We do see stars ...
Remember Apollo 11 Post flight Press Conference : " We have not seen any star ... "
Never too late to replace an old lie belief by truth and evidence
Let's have together a good day

Presumably you mean that because we could see no stars in the Apollo photos of the astronauts on the Moon, those pictures must have been faked.

OK, Giordano Bruno. The pictures of astronauts on the Moon were daylight photos, which means that the astronauts were out on the Moon while the Sun was up. Here is a daylight photo of the Earth. Can you see any stars here?

Click to view full size image

See any stars? No?

This is a photo of the Earth at night. The Moon is up, but the Sun is down. Can you see any stars?

Click to view full size image

Yes, look carefully, and you can see the constellation Scorpius to the left of the Moon.

Ah, but now you object, perhaps, that the daylight sky of the Moon is different from the daylight sky of the Earth. The daylight sky of the Earth is bright, but the daylight sky of the Moon is always black. So we ought to see the stars in that blackness. Right?

Wrong. Because the Sun is always right there in the daylight sky of the Moon. The Sun is right there - and it is brighter than it is on the Earth, precisely because the sky of the Moon is black. When you try to look at the stars in the blackness of the daylight sky of the Moon, you are always looking more or less straight at the blinding Sun. Do you think you'll see any stars?

Click to view full size image

See any stars? No?

Lesson number one, Giordano Bruno. When the Sun is up in the sky, you don't see any stars.

So why are there stars in today's APOD? Why, because Endeavour has just flown into the Earth's shadow. The Sun is behind us. It is night. Look at the dark face of the Earth. It is night. We are not looking at the Sun.

And that's why we can see the stars.

Ann

[orin stepanek]

Ann; the disbelievers are always among us!
Orin

[Asya]

What is that purple light seen on Earth's surface on the left??

[Ann]

Perhaps you still don't accept my line of reasoning, Giordano Bruno. Perhaps you say that the camera that snapped the Apollo photos was never looking straight at the Sun. Instead, the Sun was always behind the camera. So the camera ought not to have been blinded, and the sky was black, so clearly we should have seen stars in the sky. Right?

Wrong. Take a look at this youtube video from downtown Las Vegas at night. See any stars?

Click to play embedded YouTube video.

See any stars? No, you don't, because all the lights in the sky are artificial.

Why don't we see any stars here? Because the city is too brightly lit up. The bright lights of Las Vegas overwhelm the faint lights of the stars. Remember, however, that the bright lights of night-time Las Vegas are nowhere near as bright as the daytime Sun of the Moon. The Moon is lit up far, far brighter by the Sun than Las Vegas is ever lit up at night.

You just can't see any stars from the Earth or the Moon when the unocculted Sun is in their skies. Get used to it.

Ann

[GordonR]

First the speed was wrong -- 27,000 mph. Then the grammar is wrong. "Endeavour made a it's final landing . . ." "It's" is short for "it is". The possessive is "its", without the apostrophe.

[owlice]

Amazingly enough, the APOD editors are (gasp!) human!

[Mike K]

Is that thick layer at the horizon that you can see stars through the Earth's atmosphere? I'm surprised it looks that thick.

[neufer]

What is that purple light seen on Earth's surface on the left??

Blue lightning reddened by a long optical passage through the atmosphere?

http://apod.nasa.gov/apod/ap100419.html

Lightning photographs: The hue of lightning channels in photographs is usually a function of the type of film, camera, exposure and/or recording media used. The same lightning channel can appear blue, purple, red or orange depending on the type of film, length of exposure, and other factors. Slide film is more likely to produce a more purple/blue image, while print film tends to give lightning a more yellow/orange tint. >>

Your reference to different emulsions producing different colors isn't very relevant to a digital image like this. In fact, lightning ionizes nitrogen, which results in the purple color seen here. The main lightning path is saturated, making it appear nearly white. Less bright paths show as a combination of the blue-white thermal continuum and the purple output of ionized nitrogen. The color of lightning can be further modified by scattering processes, depending on the amount of dust, rain, or hail in the air.

[Fixxxer]

What's the red band going across the frame just above the horizon? Is it just an upper-layer of the atmosphere?

[neufer]

What's the red band going across the frame just above the horizon?
Is it just an upper-layer of the atmosphere?

http://apod.nasa.gov/apod/ap100216.html

[gar37bic]

What's the red band going across the frame just above the horizon? Is it just an upper-layer of the atmosphere?

I'm curious about this too. I assume that the atmosphere appears as that skinny blue band with yellow and green. So what is that reddish band? It follows the curve of the Earth, but it appears to be several hundred miles above the earth, if it is a real Earth-surrounding phenomenon and not some kind of camera effect. If it weren't so high I could think it might be a sort of sunset effect - the last bit of red light 'bent' around the atmosphere. But the atmosphere just isn't that thick compared to the Earth's diameter.

Neuter's reply (http://asterisk.apod.com/posting.php?mo ... #ppr149600) does not apply, I think. That picture is a very different scale, so close that the curvature of the Earth is not very apparent whereas at the scale of this picture the atmosphere is just a thin 'skin'. In this picture the red band must be 400-500 miles above the Earth's surface. (One can extrapolate from the picture - take two perpendiculars from the Earth's surface on the opposite sides of the picture, and where they meet. about the height of the picture below the frame, we can estimate the center of the Earth. That is about 4000 miles from the surface. The red band is about 1/10th of that distance above the surface - ergo, 400 miles.)

[gar37bic]

It also seems to be too _low_ to be the geocorona!

[neufer]

What's the red band going across the frame just above the horizon? Is it just an upper-layer of the atmosphere?

Neuter's reply does not apply, I think.

Well... at least "Fixxxer" didn't call me Neuter.

Sam Spade

[Amir]

I have something to say regarding Giordano Bruno's question and Ann's response. I may be wrong, but if someone asked me 'why there are no stars in the pictures taken out of the Earth? (e.g. on the Moon)' or 'why Apollo crews said they have not seen any stars?', I would've answered that because those picture were taken somewhere that was lit up by the Sun, sub-second exposure time was selected and that's why there are no stars. but in the pictures which were taken in the absence of the Sun, multi-second exposure time was needed to gather enough light of the objects around, and that's why stars appeared too... like today's APOD.
and the reason Apollo crews haven't seen any stars, is the same reason that when we go home in a sunny day and we cannot see anything at first; our eyes are not dark adapted to see less illuminated things. I think if Apollo crews blocked the Sun and surface of the Moon (and anything else that reflected sunlight) out of their view and let their eyes get dark adapted they would have seen some stars... sun would not have made any problem since there is no atmosphere to reflect it.

I say the reasons that make it impossible for us to see the stars daytime are:
1. our pupils are not opened enough to let us see the stars.
2. reflected sunlight from atmosphere is brighter than stars.

[rstevenson]

You just can't see any stars from the Earth or the Moon when the unocculted Sun is in their skies. Get used to it.

You may have overstated your case there Ann.

Let's go stand on the Moon for a few minutes, wearing the very latest in space suits. Let's time our arrival before mid-morning or after mid-afternoon so the sun isn't directly overhead. Now turn your back to the Sun and raise your head (tilt back, I guess, since the helmets don't move much) so that you can't see any of the surface in your visor. (I know, you said "unocculted" and I just proposed occulting the Sun with your helmet.) Now wait for a few minutes for your eyes to adjust. You'll see stars, and not just because you tilted back too far and fell over. You'll see stars for the same reason you can see them from your back yard at night, once your eyes dark adapt -- because there's no atmospheric water vapour and dust to spread the sunlight around.

Cameras react similarly to our eyes. The Apollo astronauts could have taken photos of the surface which showed stars in the background, but they'd have needed a strong graduated neutral density filter on the lens -- one that left the upper portion of the image unfiltered -- so that a longer exposure could image the stars without washing out the surface detail. Of course they never bothered doing that, but it would work. I'd be happy to take the next train up and prove it -- if I could just find the platform it leaves from.

Rob

[spameroo]

Um, Ann, I understand the temptation to get defensive against people putting forth bunk... even the temptation to go overboard with multiple posts and lines of reasoning... but...

"Never too late to replace an old lie belief by truth and evidence "

Am I the only one who took this to be saying the exact same thing you are? It's possible you have prior experience with this guy and know from that that he believes the "omglol no stars lol" crap... but I reeally don't get that from his post here. I read it as "hah! Take that Apollo doubters! Never too late to put a long-standing lie or misbelief to rest by presenting truth and evidence. Now let's move forward."

I know there are plenty of ignorant people who actually believe the Apollo astronauts didn't see any stars because the moon landing was all faked... But launching into a breathless diatribe spanning multiple posts at the first mention of an anti-science conspiracy theory is NOT the way to encourage understanding of the facts and evidence. It does harm to the cause of promoting science and rational thought, in my opinion... Especially when the person you're attacking is on the same side of the issue as you, which might have become clear if you had attempted to understand what was written, instead of launching into a hostile rant based on your admitted presumption of his meaning.

[Ann]

spameroo, I may have been wrong in my interpretation of what Giordano Bruno was saying. If so, I apologize.

Ann

[islader2]

Bruno, one cannot see stars in this APOD because--as you-well know--Earth is flat! Planeta planus est. (yuk, yuk and har, har)