Wednesday, March 07, 2007

Starry Night?

Gary asks:
"I have a serious question I need answered. Whenever the space shuttle astronauts take pictures why can't we see any stars in the background anywhere?
Also when they landed on the moon and snapped pics of the earth, where in creation is the stars at? This has always troubled me because at night I see the stars but when they snap photos in space it's all black.
Please explain? This is something I've never understood?"

I'm not sure. It could be because the moonlanding was fake as some say. Or it could be because they were photographing sun-lit objects (the Earth or the Moon), and so the stars are too faint to show up in comparison. When you see the stars at night, there are no huge sun-lit objects to cause your pupils to contract.

Oooh, I just remembered, back in school we were told that if you stand at the bottom of a well, you can see stars in the small piece of sky above. It didn't make sense to me back then because I thought it was the blue of the sky which was too bright for the stars. But if instead it is the daylight on the landscape around you doing it, then that datum makes sense.
... I still don't quite see why the sky would not be too bright all by itself to show any stars though. Ah well.

15 comments:

Michael Burton said...

All the manned spacecraft photos we're familiar with were taken to show objects brightly lit by the sun, so lens apertures and shutter speeds are not appropriate to capture the very faint light of stars. Here's how a website at the University of Wisconsin explains it:

"The Apollo astronauts all landed on the day side of the moon, and all the videos they shot from orbit were over the day side, so the exposure settings were all for daylight. Set your camera to 1/125 at f/8 (a setting typical of the slower films in use in 1969). Aim it at the night sky and shoot pictures. Tell me how many stars you see. Aim your camcorder at the sky and see how many stars you can film."

The same effect applies to photography from the space shuttle during the daylight portion of its orbit.

Apollo astronauts, including the moon walkers, reported that they could not see stars with the naked eye, even during the long coast from the earth to the moon. They were able to see stars through a sextant that was used to confirm the spacecraft's position and orientation, and they saw lots and lots of stars through the windows when the spacecraft moved into the shadow of the moon. I assume the same effect would be true in earth orbit, but I've never heard a first-person account of that.

Pascal said...

Michael,

That was a hugely interesting link. Thank you.

terry said...

i still don't understand this. the sun is bright, the moon relects the sun's light, our other neighboring planets can be seen, yet not one single star is in view. just plain incredible.
so you must slide into a shawow to see any stars?
so whole distant galaxies are literally hidden by light? just doesn't make sense.

damien said...

The eye can capture a wider range of shades than a camera, but still it cannot see all of them at once. It needs to adapt the brightest object in view, and loses sensitivity in the darker areas.
This is why you cannot see the milky way in a city where the sky is flooded with light, whereas it stands out so clearly in rural areas.

M Beep behind the Moon said...

Once upon a time we were all sitting in front of our TV sets, in feverish amazement and admiration of the first astronauts on the moon. And Uncle Sam was a good friend.
Was it the beginning of a misconception? Was it true adventuring into space, or was Uncle Sam only showing off, trying to be ahead of the USSR?
I think both is true. And today? Uncle Sam has become an old man.
Playing no role anymore in modern technology, especially to save the earth. His leadership has withered.
Anyway, thanks, Sam, for coming to the rescue of Germany decades ago, giving back freedom to our people.

(Sorry it's a bit off topic)

Lee said...

It has to do with the effects of the atmosphere adding 'sparkle' to the otherwise very small stars. That's about all I know.

Oh, happy birthday, Friday Melbourne time, Eolake.

eolake said...

Hah. Thanks, dude.

terry said...

Anyway, thanks, Sam, for coming to the rescue of Germany decades ago, giving back freedom to our people.

To M Beep,
My father-in-law was in England when the Nazi's were bombing it and He was also in northern Africa.
He said he would do it all over again to save Germany and the world from Hitler.(He served in the U.S. Army.)
My father-in-law passed away in 1992, but I'm sure today he would say, "Your Welcome."
I still believe that America is still the greatest country ever (forgive 1/2 the country for Bush) for when He leaves office perhaps we can regain the world's respect.

Monsieur Beep said...

Terry, many feel as you do.

GWB is too stubborn and too religious.

I hope all goes well until the end of his term. In the end he might have thought well for his country, but he isn't a gifted leader, right?

Pascal said...

Monsieur Beep said...
"In the end [GWB] might have thought well for his country"


Very generous from you to give him so much credit. Your optimism feels... cute! :-/

But I don't trust Democrats much more, either (only a little bit). In spite of how good a President Clinton was for his country, I'm still waiting for somebody to explain to me the first shred of sense behind that whole bloody Kosovo mess. Looks like it was only a deliberate plot to screw the Europe of Security and Peace, and the influence of Russia there. And today, it's pay-back BIG time for Comrades Putin and Hu Jintao, who don't hesitate to support Iran for obvious reasons of spite and influence. (Remember that triple missile strike on the Chinese Embassy in Belgrad? Well, China hasn't forgotten either. Or forgiven.)

Milosevic was a warm-up training for Saddam. Alledgedly, he was pretexting a "false secessionist plan" from Kosovo in order to oppress it. So Serbia was enthusiastically half-levelled.
Nowadays, after a reverse ethnic cleansing of nearly all Serbs in Kosovo in front of a powerless UN administration, the separatists have been "democratically elected", and the only "reasonable" political outcome proposed by these same righteous UN is a de facto independance, most likely a first step before they choose to unite with Albania!

I wonder... Why doesn't the world wage war on Turkey for denying the Kurds their autonomy? On France, following the claims of some Basques and people in Corsica? On the UK, for remaining in Ulster? And on Washington for imposing their racial mixity laws on Southern States (subdued after a fierce military campaign, BTW)? Forget the cat : the whole pack of rabid tigers is out of the bag!

I globally have much admiration for Bill Clinton, but he really f***ed-up with this one.

Not to mention that Lebanon was OFFERED to Syria for 15 years, as a prize and reward after Assad Sr supported the first Gulf War against Iraq. (But why would any Lebanese hold bitterness, right?)

As for the noble attitudes of WW2, a few reminders :
- The USA stubbornly refused to go to war against a clear planetary threat, until that bitter threat bit their butts in Pearl Harbor.
- If it wasn't for De Gaulle's unrelenting efforts, the liberated France was terribly close to becoming a protectorate, like Germany. To this day, The portrayal of Charles De Gaulle in US movies is that of a useless, pathetic, outdated, rigid scarecrow. To the French, he's their George Washington...
- Germany was split between its "noble" Allies, effectively handing half of it directly to Stalin... and all that ensued.
- WW2 was barely over that the Cold War had already begun.

Nothing noble in all that. Just a fortuitous converging of temporary interests. Mostly, stinky interests. One word : Yalta.

"Clio (the muse of History) is a whore, and she's always in the victor's bed." (Jean-Charles, French school teacher.)

Tell you what : because I'm a polite chap and we're among friends and pleasant company, I'll abstain from stating any further opinions on the moral politics of any powerful nation, present or past. It's not worth the ulcer.

Let us dream upon the stars. No two frontiered bits of land on this planet are true friends. Not yet. The children inside them have yet to grow up and stop bickering.
("Just you wait! I'm telling Dayy God, and he'll sent you to Hell, serves you right!")

Last night, in my dreams, I flew again. I'm getting real good at flying. I go high, I go far, I go fast, I leap over tall buildings in a single bound, light as a feather... and all I see from above is beauty and peace. And the occasional collision with a bird or a sycomore branch. :-)
Let us dream. And bring our dreams to the real world.

It is only up to us to clear the smog and see the stars again.

Typo correction! Pascal said...

That should read :

"I'm telling Daddy God"

Monsieur Beep said...

Pascal I agree with you on what you write and on your perception of the political world.

There's a two-level system: the ordinary people level (not "the U.S." "Germany" etc) and the political level (politicians speak of "the U.S." Germany" etc, as if all members of the nations supported what the politicians say).
I belong to the ordinary level and back in the 1950s, aged 10 or so, I couldn't think of any better country than the USA. The Atlantic was just a pond, whereas Eastern Europe was in another galaxy. I was looking forward to that roll of bw movie-film with the latest news from New York which was shown weekly on German TV. I enjoyed all the Wild West films. The childrens' programmes - Fury, the horse, was my favourite.
And then Elvis. I do have good memories of the U.S. indeed.

But: today, I share your perception as well, Pascal.

Pascal, citizen of the World, said...

Monsieur Beep said...
"There's a two-level system: the ordinary people level and the political level."


Perfectly correct. Which is why I'll never be "into" xenophobia.
I can't stand the guts of the Syrian regime. However, the guardian of our neighbor's house (his summer residence), and the husband of our housemaid, are both syrians. Civilians, ordinary people. And friends.
Better friends, sometimes, than some Lebanese, even some family members. These days, a lot of people are politically polarized, and identifying themselves with the party they support. The last family reunion was not very pleasant. I hope this idiocy will be short-lived. I've always refused to mix politics with family and friends (as long as they're not active milicia members!). Great for one's serenity, and it preserved me many friendships.
It's such a hassle to keep enemies, isn't it? :-)

"The Atlantic was just a pond, whereas Eastern Europe was in another galaxy."
It would be funny if it weren't so true. When I go to France, I instantly feel like I've switched planets. A dangerous illusion sometimes : global warming snickers at frontiers.

American politics suck. Like nearly all politics. But America is a great country inhabited by lots of excellent peace-loving and friendly folks. Seating Pascal has spoken, how!

I don't know... am I a hopeless dreamer for expecting that some day, the countries will stop being sickeningly schizophrenic like this? Tolerance and coexistence are not so hard. I know, I've tried.

"When you wish upon a star, lalalala..."

terry said...

Monsieur Beep said...
Terry, many feel as you do.

GWB is too stubborn and too religious.

I hope all goes well until the end of his term. In the end he might have thought well for his country, but he isn't a gifted leader, right?

That's true M Beep. He's also an embarrasment to our great nation for illegally invading Iraq and deceiving millions with his ongoing lies and manipulations.


I globally have much admiration for Bill Clinton, but he really f***ed-up with this one. Pascal said.

It hurts me somewhat that you think President Clinton screwed up.
I still love my country very deeply and would never leave it. But Clinton was human and made mistakes. But as an American I am still very proud of our accomplishments throughout the ages.
We are the only country I know of that has to block people from trying to get in. AKA (Mexicans)
I'm glad M Beep that you have fond memories of America. I love her still today and will defend her if she were ever attacked.
If America ever falls, the world is doomed. I know some may disagree with my statement but I feel it's true. I am blessed to be an American.
But I'm also ashamed of Bush who has caused a civil war in Iraq. For that, I'm sorry, but I didn't vote for him.
And actually Pascal, the democrats will change our nation once the heartless sociopath is gone or impeached.

Pascal said...

Terry said...
"It hurts me somewhat that you think President Clinton screwed up."


As I said, it hurts me too, but he did. At least this once. What's the difference between the Kosovo mess and Iraq? A needless war, based on lies, against a dictator no worse than many friendly ones, and no exit strategy to solve a problem that was only made worse.
Wait! There IS one difference : the Serbs are not terrorists. They're civilized enough to not target their own civilians or do suicide bombings against UN troops.

Which makes Kosovo, in a way, a worse mistake. Because "we" (the righteous world) have wronged a country and people which, in average, were quite decent. Compare, for instance, with the Darfur. For years now, hundreds of thousands of victims, in broad daylight. 10 to 100 times worse than anything Milosevic ever caused. Perhaps as many dead as there are INHABITANTS in all of Kosovo! But maybe "they're just n******s", right? So nobody out there really cares.

I like Clinton, but on the day of Accounts, bonking Monika will be a very trivial worry of his. Unjustly ravaging a country is infinitely worse. The war probably killed more Serbian victims than SOME of the Serbs are charged with causing. And the Kosovars are doing to the Serbs (all of them) exactly what was blamed from the Serbs (some of them). Will THEY, the Kosovars, be bombed for ethnic cleansing too? Plus, theirs is far more efficient. Nearly completed, and irreversible.
Which is why US media keep most neys about former Yugoslavia in the paper bin. It's nothing to brag about...

Two wrongs never make a right. Never. Especially "righting" a wrong with a bigger one!!!

"We are the only country I know of that has to block people from trying to get in."

Then you don't know many countries very well. Spain, Italy, and most of Western Europe are constantly struggling to keep African, Middle-Eastern, East-European and Asian clandestine immigrants from rushing in. Often at the price of their life. Very few Mexicans drown from crossing the Rio Grande on overloaded rickety canoes. THEY don't cross the ocean in any season regardless, or risk freezing by grabbing to an airliner's landing gear. The Boat-People are still there, man. And as desperate as always.

"the democrats will change our nation"
OF COURSE they will! But it's still about choosing the lesser of two evils, most of the time. In every country.
A Gandhi or a Nelson Mandela come once in a century. And very few of their friends are as upstanding once they are left on their own. I'm seeing right now in Lebanon.

A return to Democrat rule would be a great improvement. But given the circumstances, that's really not difficult. Easier than it has ever been, perhaps. :-(

Remember that two-level system : I have little trust in Democrat politicians, but it doesn't imply a thing toward their supporters. I instinctively distrust ALL politicians. Only, at varying degrees. Believe me, I can imagine even worse than Bush Jr in power. Jerry Falwell or Pat Robertson, to name but two examples.