Pictures of Earth From Mars

11223 writes "Mars Global Surveyor has snapped a picture of Earth from its Mars orbit. This picture, the first of its kind, shows Earth, the Moon, and Jupiter. Earth is visible as a half disc exposing North and South America; apparently the Moon had to be "processed" into the picture."

Slashdotted before out of "The Mysterious future"

[Binestar]

Mirror available here [atecgroup.com]. Please do not mod this up, and go gently, also once you've seen it please mirror somewhere else, this is only a T1 for gods sake! =)

Mirror?

[Ignorant Aardvark]

Whoa, I was gonna try and mirror these images ... but to no avail! The webserver stopped dead during the subscriber preview time. Oh well, here's a BitTorrent link for everything I was able to get before the site went down:

BitTorrent images mirror link [bounceme.net]

Re:Very nice.

[polymath69]

Space.com [space.com] has the pictures, and is not (yet) slashdotted.

Mirror

[realdpk]

Or maybe this is "another mirror" by the time I finish posting this. The site is getting pounded hard. This is just the JPEG that was linked to, not the entire site.

429319 byte JPEG [dpk.net]. It's on a beefy connection, have a blast.

It's really too bad /. doesn't have any consideration for other sites when they post links.

Re:Slashdotted before out of "The Mysterious futur

[KrispyKringle]

Seems like a good way to test my pII 400:

mirror here [dnsalias.net].

If you can, mirror it somewhere else, too.

Re:Images look funny

[antis0c]

I downloaded the unprocessed images of Earth. The only difference is Earth is colorized, and the moon brightness is enhanced.

Re:Very nice.

[terkozer]

National Geographic has picked up the article as well...

It can be found here [nationalgeographic.com]

Re:"Processed" into the picture?

[Clomer]

Sadly, you're probably right. Fortunately, they explained exactly how it was "processed" and why, as well as provided links to the original, unprocessed images.

The simple fact is that it is virtually impossible to get a good, unprocessed image of this type because of how much of a difference in brightness there is between the Earth and the Moon. I once read somewhere that the moon only reflects about 10% of the light that hits it. It's dark grey, essentially the color of asphalt, but it looks white in the sky because you see it against the pitch black background. The Earth, OTOH, reflects about 45% of the light that strikes it, which makes it's apparent magnitude (brightness) much higher when seen from afar. This is why they had to process it the image.

Re:Better format?

[Lxy]

what about PNG? it should give you an image of comperable size without people lashing about how evil Unisys is.

Celestia

[msheppard]

Pretty kewl to enter the date/time May 8, 9:00Est, navigate to mars and see the rendered view for yourself. Celstia lets you do this, it's a free solar system simulator. Really high-quality too IMHO. It gets the image pretty close. Make Jupiters moons a little brighter, and the earth is too clear, but it's still an educational exersize... but then again what isn't.

M@

Re:What happened

[AlabamaMike]

Ahh ... one who hasn't heard of the moon shot conspiracy. Basically, the stars are of much lower magnitude than the celestial bodies being imaged, and therefore they don't show up in this picture. Many have tried to claim that evidence of the vast NASA conspiracy lies in the fact that no stars are to be seen on any of the photos taken by Apollo astronauts. If you've had any exposure to physics (or if you can perform logical deduction on your own) you'd be keen to why this happens the way it does.
-A.M.

Re:Images look funny

[travisbecker]

Why does Jupiter look so big in that picture?

From one of the astronomy programs I have, I was able to get this data for 08-May-2003:

Earth-Mars range: 1.398e8 km
Jupiter-Mars range: 9.438e8 km

Earth radius: 6378.12 km
Jupiter radius: 71492.35 km

So using

size = atan( radius / range )

we obtain apparent sizes from Mars:

Jupiter: 0.0043 deg
Earth: 0.0026 deg

So Jupiter should be almost twice as big, even though it's almost 7 times farther away. One can probably also figure out the magnification based on the image.

Travis

Re:Better format?

[CWCarlson]

Indeed. Converted with the Gimp at compression level 6, this 429,319 byte image shrinks to a mere 40,714.

Not bad, for a 24-bit non-lossy image format.

--- Chris

Re:What happened to stars

[Anonymous Coward]

Even in space, starlight is very faint - when you expose for planets (which are just reflecting the sun's light) the star's light is just way to faint to register. If they had exposed to show the stars, both planets would just be super big blobs many many many times overexposed.

Re:"Processed" into the picture?

[geekoid]

they have NO ammunition. There 'evidence' is caused by the fact they have no understanding of basic photographic principles, and think the the moon is just like the earth.

Optimal image format

[Wonko42]

Is there some reason why this image, which is mostly black with just a few colored fingernail-sized areas, needs to be a 419K JPEG? When I converted it to a 69K PNG, I couldn't even tell the two images apart.

Slashdotted !! Don't worry...

[Anonymous Coward]

Pics are here:

http://news.nationalgeographic.com/news/2003/05/05 22_030522_earthmars.html [nationalgeographic.com]

Here:
http://story.news.yahoo.com/news?tmpl=story&cid=62 4&ncid=753&e=10&u=/ap/20030522/ap_on_sc/earth_from _mars [yahoo.com]

Here:
http://www.spaceref.com/news/viewpr.html?pid=11583 [spaceref.com]

Here:
http://story.news.yahoo.com/news?tmpl=story&u=/030 522/168/45jfk.html [yahoo.com]

Here:
http://www.cnn.com/2003/TECH/space/05/22/earth.mar s.ap/ [cnn.com]

And Here:
http://abcnews.go.com/sections/scitech/World/viewo fearth030522.html [go.com]

Here is a pic of earth taken by the Voyager 1 spacecraft in 1991 from more than 4 billion miles away (showing only a dot):
http://www.space.com/scienceastronomy/astronomy/to p10_images_010925-11.html [space.com]

Posting as AC, I don't seek any karma. Mod up if you want to

Re:Very nice.

[Anonymous Coward]

if you want the full resolution tiffs (and jpgs too) look at the jpl site:

jupiter and moons [nasa.gov]

earth and moon [nasa.gov]

itty bitty earth and jupiter [nasa.gov]

Re:Celestia

[Anonymous Coward]

Celestia homepage [sourceforge.net]

Fast and working mirror

[Anonymous Coward]

This seems to be a fast mirror: http://nwps.ws/mars_images/ [nwps.ws]

Re:Fake fake fake

[KewlPC]

For those not in the know, it should've been "Consume." and "Marry and Reproduce."

They're from the John Carpenter film They Live [imdb.com], in which aliens are trying to take over the planet, and have bribed some human leaders into helping. The aliens masquerade as humans, and insert subliminal messages into advertisements. Roddy Piper, who plays the protagonist, finds a special pair of sunglasses that allow him to see things as they really are. There's a scene where he walks outside and sees some billboards. Then he puts on the sunglasses, and sees what the billboards really say: one says "Consume", another says "Marry and reproduce".

Re:Makes you realize how big Jupiter is...

[ashitaka]

One word: Celestia [shatters.net]

Re:Better format?

[KewlPC]

Except that GIFs can only have 8-bit indexed color, which means you've got a maximum of 256 different colors.

Both PNG and JPEG support 24-bit true color (which uses 8 bits for each channel, and is not indexed), giving a maximum of around 16.7 million colors.

Re:Hmmmm, interesting

[Jeffv323]

I bet most of what you see are compression artifacts. I just turned up the contrast on the JPEG for kicks, and what interests me, is the fact that the shadow side of the earth becomes visible. Maybe it could be due to refraction of light in the atmosphere or actual city lights (could it?) but I don't know enough about optics and light to answer that. At least jpeg compression could be ruled out.

Here's [jdccs.com] the original. Here's [jdccs.com] my version.

Also, somebody said something about the original grayscale GIF right from the camera being available. I couldn't find it but if anybody else has it, please post a link.

-- Jeff

Re:Hmmmm, interesting

[Zakabog]

Someone explained this before, but if you want a picture of the planets with stars, the planets will be overexposed. If you want the planets exposed correctly the stars will be too dark to see. Besides turning up contrast and brightness isn't going to expose the image more, if I take a picture with a 1/2000 shutter speed of a dark room, no amount of brightness, contrast, changing will make it a clear picture.

Re:Hmmmm, interesting

[laughing_badger]

Astronomer, image processing guy, blah blah... Right, there will be sufficient light from the sun scattered from the illuminated atmosphere and then rescattered from the dark hemisphere towards the camera to make the dark hemisphere visable. You can see a similar effect by looking at a half moon on a dark night. You will be able to see the 'dark' side of the moon illuminated by light that has been reflected from the surface of the Earth. Its called Earthshine.

Yep, bang on about most of the effects that the parent saw being compression artifacts.

Ok, now as to why there are no stars. The Earth recieves a lot more solar radiation than Mars (distance squared). Presume that the albedo (amount reflected) is the same. So you have a lot more photons going into your camera if you take a picture of the Earth from Mars than vv. This means that you can use a shorter exposure and hence less stars will appear. Then do JPEG compression and watch the few point-like stars get smoothed out. Also, we don't know what else has been done to the image. Subsample and point like stars can go.

If you want to hunt around in the depths of an image looking for cool stuff, start off with an unprocessed original.

Re:Nice pics of home

[bill_mcgonigle]

Staggering that they could even get that pic.

They didn't, technically. The camera on the MGS is grayscale. They used stock photos to apply color to the images. They're totally forthcoming about this and the technique [msss.com] if you go straight to the source.