APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

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Expand view Topic review: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

Re: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

by SFCass » Sat Jun 30, 2012 7:07 am

Ann: Thank you for the thorough and fascinating explanation for the missing stars!

Re: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

by Mactavish » Wed Jun 27, 2012 7:03 am

Mactavish wrote:The full panorama is even more spectacular!
My apology for not including the link to the full panorama. It was APOD Dec 14, 2007. http://apod.nasa.gov/apod/ap071214.html

Re: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

by rstevenson » Tue Jun 26, 2012 12:41 pm

Dreadmon wrote:Odd that you don't see the rover's tracks in the picture.
It's easier to see some soil disturbance, which I assume indicates the tracks of the rover, on the full panorama picture (linked above.) The disturbed soil is whitish, as you can see around the front of the rover where the astronaut has been walking.

Rob

Re: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

by Dreadmon » Tue Jun 26, 2012 4:30 am

Odd that you don't see the rover's tracks in the picture.

Re: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

by eltodesukane » Mon Jun 25, 2012 9:10 pm

Chris Peterson wrote:
Ann wrote:One of the best arguments that I've ever heard against the claim that the Moon landings were a hoax is that this happened during the height of the Cold War. After all, the Moon landings were just as much about the United States beating the Soviet Union as it was about exploring the Moon...
I've always thought that was a good argument, as well, although hoaxers make a (very weak) case for mutual support of fake space programs.

There's a really good technical demonstration that the landings were real- one which is completely devastating to any suggestion that the imagery was faked. We can see in the movies that the astronauts are operating in a vacuum. How can we tell? By the way the dust flies when they walk, or when the rovers move. Dust in even thin air is very non-ballistic in its motion. With its very low mass, its behavior is dominated by aerodynamic effects, not gravity. Toss a little dust in the air, and you get a cloud that floats off. But the Apollo films show something very different (I love using them in the classroom, because everybody instantly recognizes that something looks "wrong", but it can take a while before anybody figures out what that is)- the dust moves in beautiful little parabolic arcs, purely ballistic. Certainly, no CGI capability existed back then to fake that, so it could only be done in a vacuum. The suggestion that everything was filmed in massive vacuum chambers just adds to the absurdity of hoaxers claims (especially since the same people often suggest the flags are blowing in the wind).
The best argument is this:
Between "going to the Moon" and "faking going to the Moon", they choose the easiest way by far: going to the Moon.

Re: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

by eltodesukane » Mon Jun 25, 2012 8:57 pm

Re: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

by Chris Peterson » Mon Jun 25, 2012 3:59 pm

Ann wrote:One of the best arguments that I've ever heard against the claim that the Moon landings were a hoax is that this happened during the height of the Cold War. After all, the Moon landings were just as much about the United States beating the Soviet Union as it was about exploring the Moon...
I've always thought that was a good argument, as well, although hoaxers make a (very weak) case for mutual support of fake space programs.

There's a really good technical demonstration that the landings were real- one which is completely devastating to any suggestion that the imagery was faked. We can see in the movies that the astronauts are operating in a vacuum. How can we tell? By the way the dust flies when they walk, or when the rovers move. Dust in even thin air is very non-ballistic in its motion. With its very low mass, its behavior is dominated by aerodynamic effects, not gravity. Toss a little dust in the air, and you get a cloud that floats off. But the Apollo films show something very different (I love using them in the classroom, because everybody instantly recognizes that something looks "wrong", but it can take a while before anybody figures out what that is)- the dust moves in beautiful little parabolic arcs, purely ballistic. Certainly, no CGI capability existed back then to fake that, so it could only be done in a vacuum. The suggestion that everything was filmed in massive vacuum chambers just adds to the absurdity of hoaxers claims (especially since the same people often suggest the flags are blowing in the wind).

Re: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

by neufer » Mon Jun 25, 2012 12:21 pm

Chris Peterson wrote:
That said, the thrust of the lander motor was higher than it appears in images. Rockets don't normally produce much visible output, unless they are in the atmosphere. So the Saturn boosters appear more powerful than they actually are, and the lander boosters appear less so. (Not that the Saturn motors weren't vastly more powerful... after all, the fuel laden Saturn with its payload massed nearly 3 million kg, compared with the lunar module ascent stage mass of less than 5000 kg, and the latter with no atmospheric drag and 1/6 the surface gravity.)
Also import is the fact that at just ¼ the orbital diameter
½ the velocity will give the same orbital centrifugal force.
.....................................................................
Earth Orbital velocity ~ 2 X rocket exhaust gas velocity Ve
Lunar Orbital velocity ~ ½ X rocket exhaust gas velocity Ve

Code: Select all

7.91 km/s  :  Earth Orbital velocity 	
1.68 km/s  :  Lunar Orbital velocity 	
................................................
Exhaust gas velocity Ve for rocket engines:
2.9 to 4.5 km/s  :  liquid bipropellants
2.1 to 3.2 km/s  :  solid propellants
1.7 to 2.9 km/s  :  liquid monopropellants
NASA Saturn V thrust: 34,000,000 Newtons (~ 2100 LEMs)
Black Brant III thrust: 49,000 Newtons (~ 3 LEMs)
NASA LEM thrust: 16,000 Newtons (~ 530 ESTESs :arrow: )
ESTES Saturn V thrust: ~30 Newtons ~(1/100 scale)3

Re: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

by bystander » Mon Jun 25, 2012 7:34 am

Re: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

by Flase » Mon Jun 25, 2012 7:17 am

Of course under fascist regimes particularly, the propaganda of football results was taken very seriously and ... influenced. Particularly famous is the history between Real Madrid and Barcelona under Franco...

Also in sport there can be match-fixing from betting syndicates. The cricket world has recently been rocked by a few such scandals and I wouldn't be surprised if it happens in American sport.

Re: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

by Ann » Mon Jun 25, 2012 6:35 am

One of the best arguments that I've ever heard against the claim that the Moon landings were a hoax is that this happened during the height of the Cold War. After all, the Moon landings were just as much about the United States beating the Soviet Union as it was about exploring the Moon.

Remember that the Soviet Union had made it into space themselves, and they had various equipment to help them monitor what the Apollo spacecraft were doing. You can be sure that they could see that the Apollo craft really did lift off and really did proceed towards the Moon. They could also make sure that the voice of Neil Armstrong (and other astronauts later on) really did come from the Moon and not from a studio in the Nevada desert.

In other words, the Soviet Union leaders, who would have loved to expose the Apollo landings as a fake, never questioned the authenticity of the landings.

Which makes me wonder: What is it about people in the West these days who want to prove, decades later, that "their own" Moon landings never happened?
Can't resist telling you about a weird Swedish conspiracy. In 1958, the Football (=soccer) World Championship was held in Sweden, and the Swedish team did so well that they reached the final, where they were soundly beaten by Brazil. However, nowadays some Swedes are saying that Sweden can't possibly have played so well and made it so far, and some of them claim that the entire Football World Championships in Sweden in 1958 must be a fake!!

What is it with some people nowadays?

Ann

Re: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

by Flase » Mon Jun 25, 2012 6:17 am

Yeah nah I'm willing to believe that it's deceptive.

Re: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

by Chris Peterson » Mon Jun 25, 2012 4:31 am

Flase wrote:The only thing that doesn't look right to me is how small the Lunar lander was. With a little puff of flame, it was able to reach the Moon's escape velocity, whereas craft that takeoff from Earth require huge whopping booster rockets...
Actually, none of the Apollo spacecraft reached escape velocity with respect to either the Earth or the Moon. They never left orbit from the Earth-Moon system, and were only boosted to a slightly faster velocity than the orbital velocities they were initially lifted into.

That said, the thrust of the lander motor was higher than it appears in images. Rockets don't normally produce much visible output, unless they are in the atmosphere. So the Saturn boosters appear more powerful than they actually are, and the lander boosters appear less so. (Not that the Saturn motors weren't vastly more powerful... after all, the fuel laden Saturn with its payload massed nearly 3 million kg, compared with the lunar module ascent stage mass of less than 5000 kg, and the latter with no atmospheric drag and 1/6 the surface gravity.)

Re: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

by Flase » Mon Jun 25, 2012 3:36 am

If the Moon landings were a hoax, they were much better than I would expect from the American military. Even 2001 A Space Odyssey from the same year (1969) was less realistic.

The only thing that doesn't look right to me is how small the Lunar lander was. With a little puff of flame, it was able to reach the Moon's escape velocity, whereas craft that takeoff from Earth require huge whopping booster rockets...
http://news.nationalgeographic.com/news ... 44445.html

If it's a hoax, I'm willing to admit I'm a sucker for it because it's such a good one.

Re: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

by rigelan » Mon Jun 25, 2012 12:04 am

Man, what an experience to actually walk the edge of the crater on the moon!

Re: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

by eltodesukane » Sun Jun 24, 2012 9:16 pm

In December of 1972, Apollo 17 ... ... almost 40 years ago.

Re: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

by neufer » Sun Jun 24, 2012 4:24 pm

Chris Peterson wrote:
Ann wrote:
The lunar sky is always black, because the Moon has no atmosphere. But when the Sun is up, it shines more brilliantly than it does on the Earth. That is precisely because the Earth has an atmosphere, and some of the sunlight is scattered in the Earth's atmosphere, diluting the Sun's most intense glare. On the Moon the Sun is like an unbelievably white-hot spotlight in the black sky.
That's technically correct, but the actual increase in brightness of the Sun as seen from the Moon is less than a magnitude compared with Earth. Physiologically, the Sun appears no brighter when seen from the Moon or from space.

"where oranges have been laid to rust"

by neufer » Sun Jun 24, 2012 3:57 pm

APOD Robot wrote:Image Apollo 17 at Shorty Crater

The image shows Schmitt on the left with the lunar rover at the edge of Shorty Crater,
near the spot where geologist Schmitt discovered orange lunar soil.
  • The great fall of the offwall entailed at such short notice the pftjschute of Finnegan,
    erse solid man, that the humptyhillhead of humself prumptly sends
    an unquiring one well to the west in quest of his tumptytumtoes:
    and their upturnpikepointandplace is at the knock out in the park
    where oranges have been laid to rust upon the green since devlinsfirst loved livvy.

Re: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

by Chris Peterson » Sun Jun 24, 2012 2:30 pm

Ann wrote:Yes, the sky is black in today's APOD. The lunar sky is always black, because the Moon has no atmosphere. But when the Sun is up, it shines more brilliantly than it does on the Earth. That is precisely because the Earth has an atmosphere, and some of the sunlight is scattered in the Earth's atmosphere, diluting the Sun's most intense glare. On the Moon the Sun is like an unbelievably white-hot spotlight in the black sky.
That's technically correct, but the actual increase in brightness of the Sun as seen from the Moon is less than a magnitude compared with Earth. Physiologically, the Sun appears no brighter when seen from the Moon or from space.
The contrast between brightness and darkness becomes intolerable. Even if you look away from the Sun, the contrast between the brilliantly lit-up lunar landscape and the black sky is so great that the faint stars are completely drowned out.
Photographically, that's certainly true. But the lunar surface is about the same color and reflectivity as coal, so it reflects less light than most ground on the Earth. The astronauts reported that they could see stars if they were out of the direct light. The biggest problem for them in this regard was the filters in their helmet visors. They were basically wearing super sunglasses.

Re: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

by Chris Peterson » Sun Jun 24, 2012 2:18 pm

no one wrote:What Magnitude star would have been necessary to have been visible in the photo??
You can estimate the f-stop and time for the exposure if the documentation is unavailable.
Venus (mag -4) occasionally shows up in lunar images, and images of the Earth from ISS.

Re: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

by neufer » Sun Jun 24, 2012 2:16 pm

Giordano Bruno wrote:
I understand the shadow of anything standing on Moon's Taurus Valley between 12 and 14 december 1972 should cast a shadow at least as long as the height of the objet itself.

Which is not the case on the picture presented.

" There is a mystery or a lie " . ( quoted from Inspector Columbo )
The sun is behind the photographer such that the elongated shadows are either foreshortened or hidden by the objects themselves.

Inspector Jacques Clouseau: There is a time to laugh and a time not to laugh, and this is not one of them.

Re: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

by Chris Peterson » Sun Jun 24, 2012 2:15 pm

Giordano Bruno wrote:I understand the shadow of anything standing on Moon's Taurus Valley between 12 and 14 december 1972 should cast a shadow at least as long as the height of the objet itself.

Which is not the case on the picture presented.
Only because you are failing to interpret the image correctly.

You are also overlooking the fact that much of this image appears to show an area sloped towards the Sun, which raises its apparent height, and that when the Sun is behind you, objects in front cast shadows that- from your perspective- appear to have nearly the same cross-section as the objects themselves.

Re: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

by geckzilla » Sun Jun 24, 2012 2:12 pm

There's nothing wrong with the lighting in the moon photos. If you think there is, you are confused. There's no mystery to it at all. Enough insinuating. If you think the moon landings are a hoax, just say so and I can remove your post and ban your IP promptly because arguing with you is like arguing with someone who has a brain tumor.

Re: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

by Chris Peterson » Sun Jun 24, 2012 2:10 pm

Giordano Bruno wrote:The picture shows overhead illumination .
This is your error. The photo does not show overhead illumination. The Sun is behind and to the left of the photographer, and the shadows are pointing as expected. You can easily see the long shadow of the rover around the wheels... if the illumination were overhead, you wouldn't see the shadows of the wheels at all.

Of course, it's always difficult figuring out where the Sun is just by looking at shadows, either on the Earth or the Moon. Many images cover a wide enough angle that the direction of shadows varies substantially from one side to the other, and on hilly terrain direction and length is strongly influenced by the slope of the ground.

Google images for Apollo 17 and you'll see that most show long shadows, indicative of the Sun being low in the sky.

Re: APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

by Giordano Bruno » Sun Jun 24, 2012 2:04 pm

Thank you, Case,for your clear and documented mathematical explanation.

I understand the shadow of anything standing on Moon's Taurus Valley between 12 and 14 december 1972 should cast a shadow at least as long as the height of the objet itself.

Which is not the case on the picture presented.

" There is a mystery or a lie " . ( quoted from Inspector Columbo )

Daring to face strongly a single fact is sometimes the path leading from illusion to truth.

That would really be " a small step for man ,but a giant leap for mankind "

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