Pluto!

[Jesper de Jong]

Today, New Horizons flew by Pluto, and we got to see Pluto close up for the first time. Super cool!

It's going to take time before we get to see all the images that it made of Pluto, its big moon Charon and the other four small moons. There's no high-speed internet at Pluto, the bitrate is just a few hundred bits per second and you can forget about real-time communication because it's more than four light-hours away. It's going to take 16 months to download all the data that it recorded during the flyby.

[fred rosenberger]

here's an annotated photo, courtesy of xkcd:

[Bear Bibeault]

So. Freaking. Cool.

[Campbell Ritchie]

Nobody has ever been there and they have disputed territory already

[Guillermo Ishi]

Nasa photoshops its photos into looking nothing like reality, for oohs and ahhs and enthusiasm and funding. I wish they would release straight versions as well. I just want a view that looks something like it would if I was there, as uninspiring as that might be in the mind of Nasa - LOL! Even before Nasa, astronomical photos have always gotten the treatment, from the beginning.

[Bear Bibeault]

Party pooper. The visible light spectrum is b-o-o-o-o-o-o-o-o-o-o-o-ring!

[Andrew Polansky]

There is still at least one image coming. I saw on New Horizons Facebook that they are going to release an/the image(s) from the closest point of flyby today (15th).

By the way... did you know that New Horizons uses the PlayStation's CPU?

http://www.theverge.com/2015/1/15/7551365/playstation-cpu-powers-new-horizons-pluto-probe/in/8724384

[Guillermo Ishi]

Bear Bibeault wrote:Party pooper. The visible light spectrum is b-o-o-o-o-o-o-o-o-o-o-o-ring!

If I had to see x-rays and microwaves through kaleidoscope goggles on my way home, I'd probably get lost.

Hmmm, I think I'll make that fuzzy white patch purple. And that one red. And ooooh here's such a nice shade of green, I must use some of that...

[Ferdinand Victorinus]

What is the meaning of that heart formation? Is it some message from the aliens?

[Jesper de Jong]

It means Pluto loves us and isn't angry because we demoted it from planet to dwarf planet.

[Tapas Chand]

Then pluto must have done some anger management

[Ryan McGuire]

Ferdinand Victorinus wrote:What is the meaning of that heart formation? Is it some message from the aliens?

That's not a heart...

[Jesper de Jong]

I'm looking at NASA TV right now where they are showing new, higher resolution images. There are some spectacular new images with much, much higer resolution than the one above.

The "heart" now has an official name, it's now called Tombaugh Region, after Clyde Tombaugh who discovered Pluto in 1930.

[Andrew Polansky]

First released photo of Pluto during the closest approach:

http://www.nasa.gov/image-feature/the-icy-mountains-of-pluto/

[Bear Bibeault]

Oh man. Here we are, looking at close-up photos of Pluto. Pluto! How freaking cool is that?

[Jesper de Jong]

Adam Scheller wrote:By the way... did you know that New Horizons uses the PlayStation's CPU?

http://www.theverge.com/2015/1/15/7551365/playstation-cpu-powers-new-horizons-pluto-probe/in/8724384

New Horizons has two computer systems, for Command and Data Handling, and for Guidance and Control. Each of these is duplicated for redundancy. These computers contain a Mongoose-V CPU, which is a version of the MIPS R3000 CPU, but it's a special radiation-hardened version for space, and it's running at only 12 MHz.

According to Wikipedia the original PlayStation had a MIPS R3000A CPU running at 33.9 MHz.

Amazing that with such slow CPUs they can make the spacecraft do so much.

[Guillermo Ishi]

Jesper de Jong wrote:
Amazing that with such slow CPUs they can make the spacecraft do so much.

It's only got to do what it's got to do. By the way, a couple of them will set you back 80 grand...

http://synova.com/proc/mg5_price.html

[chris webster]

Guillermo Ishi wrote: I just want a view that looks something like it would if I was there, as uninspiring as that might be in the mind of Nasa...

One problem with that idea is that Pluto is 40 times further from the sun than the Earth is, do it receives 1/1600 as much light from the sun. I suspect a pair of human eyes with poor night vision and no nocturnal colour vision wouldn't be seeing very much at all.

Anyway, I see nothing wrong with most of the NASA astro images I've seen - they're a lot better and more revealing than the grey blobs I see through my backyard telescope!

[Guillermo Ishi]

chris webster wrote:

Guillermo Ishi wrote: I just want a view that looks something like it would if I was there, as uninspiring as that might be in the mind of Nasa...

One problem with that idea is that Pluto is 40 times further from the sun than the Earth is, do it receives 1/1600 as much light from the sun. I suspect a pair of human eyes with poor night vision and no nocturnal colour vision wouldn't be seeing very much at all.

Anyway, I see nothing wrong with most of the NASA astro images I've seen - they're a lot better and more revealing than the grey blobs I see through my backyard telescope!

Backyard telescopes are the pits. But only because of the colored cartoon cells that have been streaming out of Mt. Palomar since about 1947. There's bound to be a little light at Pluto or else what they're showing us is completely phony. I would like the probe to show me what it would be like to be riding on it. I want to see what it would look like to be 1000 mi. away from it, even if it's almost black against a very black. Then I would like it to turn around and show me what the Sun looks like from the same place! Without enhancement.

If the parts weren't priced like the micros that are $40,000 each we could probably afford to scoop up some of Pluto and fly it back here.

[Guillermo Ishi]

But I think what I'm asking for is technically impossible. That closeup of the surface is probably a composite of a dozen exposures with big raster lines and terrible noise with very little discernible detail. So it's probably 90% artist's rendition. Not trolling the Pluto probe, just sayin. Otherwise they'd publish the original feeds along side.

[chris webster]

Guillermo Ishi wrote:But I think what I'm asking for is technically impossible. That closeup of the surface is probably a composite of a dozen exposures with big raster lines and terrible noise with very little discernible detail. So it's probably 90% artist's rendition. Not trolling the Pluto probe, just sayin. Otherwise they'd publish the original feeds along side.

But all modern astronomical images are processed in various ways precisely because raw data is noisy or biased or because you simply cannot gather enough light in a single image so you end up layering multiple images and post-processing them to eliminate noise etc. There are cases where e.g. colours are rendered in a manner that is influenced by the "artists's" aesthetic considerations, or to make a nicely framed shot for public consumption. But much of this stuff is done for real, by and for people who want to make real scientific use of the details contained in the images. "Artist's renditions" won't give you useful data, so why should they waste time doing this when the real stuff is so cool and much more useful anyway?

Here's a shot taken by the ESA Rosetta probe around Comet 67P/Churyumov-Gerasimenko on 12 July, looking towards Pluto to see if it could actually be detected via their camera - the left-hand shot is the raw image, the others are processed:



Incidentally, you can get raw images from New Horizons long-range imaging system (LORRI) here: http://pluto.jhuapl.edu/soc/Pluto-Encounter/

And there's an explanation of the raw LORRI data here: http://pluto.jhuapl.edu/soc/Pluto-Encounter/lorri_about.php

[Jesper de Jong]

Guillermo Ishi wrote:

Jesper de Jong wrote:
Amazing that with such slow CPUs they can make the spacecraft do so much.

It's only got to do what it's got to do. ...

Still, processing all the images and science data, which is many megabytes (the spacecraft has 2 x 8 GB SSD) is going to be really slow with a 12 MHz processor. The 386SX (20 MHz) that I had in the 1990's already took a long time to decode a single JPEG image at 640 x 480 resolution. Those 12 MHz CPUs will have to work hard to process all that data.

[fred rosenberger]

Guillermo Ishi wrote:I just want a view that looks something like it would if I was there

My guess is that would be a field of stars with a big black circle in it. If my math is right, there's about 1 watt / square meter - roughly 1/6th the brightness of a standard night light. Think about what the moon looks like on the dark side - you can barely tell it's there, let alone make out any features.

The human eye really kind of sucks. Look at the image here showing the visible light spectrum as compared to the EM spectrum. We can only see a tiny sliver of it. the instruments on the probe can see a much broader range, giving many more details.

[Guillermo Ishi]

fred rosenberger wrote:

Guillermo Ishi wrote:I just want a view that looks something like it would if I was there

My guess is that would be a field of stars with a big black circle in it. If my math is right, there's about 1 watt / square meter - roughly 1/6th the brightness of a standard night light. Think about what the moon looks like on the dark side - you can barely tell it's there, let alone make out any features.

The human eye really kind of sucks. Look at the image here showing the visible light spectrum as compared to the EM spectrum. We can only see a tiny sliver of it. the instruments on the probe can see a much broader range, giving many more details.

Wow, you did the work? I just googled it
A couple of sources appear to say the light from full sun on Pluto is about like twilight here; several x a full moon.

One time I looked up how big the sun would appear from all the planets. The astronomer was saying that the apparent diameter decreases as you go out but that the brightness of that amount of disk stays the same. So from Pluto I guess Sun would be like a blinding star. The Stars besides Sun are dim because of the very small disk, I guess you could say.

Interesting poitn one time I did a back of an envelope on how loud the Sun would be if our atmosphere existed between here and there. My calculations were it was a little past off the scale, where increases in loudness quit being perceived. Now, googling says it's around 100dB; still ear on a jackhammer loud. I don't know if my method was any good. I used something like loudness of H-bomb at one mile and energy of the H-bomb and energy of the Sun and divided by distance squared.

Now see, if they had just shown us accurate photos, we would not have had to go through this

[Jesper de Jong]

I was just watching NASA TV again. They released a few new close-up images of the terrain on Pluto, one with icy planes, quite different than the mountains in the close-up picture from a few days ago.

We won't be getting many new pictures soon. The team is now going to concentrate on downloading the first batch of the science data that the various instruments recorded. It won't be before mid-September that we get to see more images.

[Bear Bibeault]

Guillermo Ishi wrote:The astronomer was saying that the apparent diameter decreases as you go out but that the brightness of that amount of disk stays the same. So from Pluto I guess Sun would be like a blinding star.

That makes no sense to me. If that were the case, then a flashlight viewed from a distance would be as blinding as close-up, just smaller, and we know that's not the case.

[Guillermo Ishi]

Bear Bibeault wrote:

Guillermo Ishi wrote:The astronomer was saying that the apparent diameter decreases as you go out but that the brightness of that amount of disk stays the same. So from Pluto I guess Sun would be like a blinding star.

That makes no sense to me. If that were the case, then a flashlight viewed from a distance would be as blinding as close-up, just smaller, and we know that's not the case.

I know. Me either. I think it comes down to if the Sun is a BB at Pluto, the luminosity is something like luminosity x 1/BB, but the brightness of the BB itself is the same; a BB sized piece of the normal Sun. The statement is "The actual surface that you see is of the same brightness. its just the area in the sky that is decreasing". Also when thinking about the brightness, remember that Pluto is much, much closer to the Sun than the solar system is to any other star.

I found the article again. I saw it a long time ago. They start talking about this in the comments. I couldn't find anything about the author, except that he's Bob King and has articles in Sky and Telescope. The article itself says the light at Pluto is 240 full moons.

http://astrobob.areavoices.com/2012/01/05/what-would-the-sun-look-like-from-jupiter-or-pluto/

[Campbell Ritchie]

It is a very long time since I did any physics but I think brightness is not ∝ 1 ÷ distance, but ∝ 1 ÷ distance².

[Greg Charles]

Campbell Ritchie wrote:It is a very long time since I did any physics but I think brightness is not ∝ 1 ÷ distance, but ∝ 1 ÷ distance².

Yep, that's the Inverse-Square Law. It's more geometry than physics, but hey ... tomato tomato. (Hmm, that analogy doesn't work so well in written form.)

[Greg Charles]

Guillermo Ishi wrote:

Bear Bibeault wrote:

Guillermo Ishi wrote:The astronomer was saying that the apparent diameter decreases as you go out but that the brightness of that amount of disk stays the same. So from Pluto I guess Sun would be like a blinding star.

That makes no sense to me. If that were the case, then a flashlight viewed from a distance would be as blinding as close-up, just smaller, and we know that's not the case.

I know. Me either. I think it comes down to if the Sun is a BB at Pluto, the luminosity is something like luminosity x 1/BB, but the brightness of the BB itself is the same; a BB sized piece of the normal Sun. The statement is "The actual surface that you see is of the same brightness. its just the area in the sky that is decreasing". Also when thinking about the brightness, remember that Pluto is much, much closer to the Sun than the solar system is to any other star.

I found the article again. I saw it a long time ago. They start talking about this in the comments. I couldn't find anything about the author, except that he's Bob King and has articles in Sky and Telescope. The article itself says the light at Pluto is 240 full moons.

http://astrobob.areavoices.com/2012/01/05/what-would-the-sun-look-like-from-jupiter-or-pluto/

IANAA (I am not an astrophysicist), but I don't think you're representing that article correctly. Yes, it says that the apparent brightness of the sun from Pluto (at one particular point in its highly eccentric orbit) would be like 240 full moons, but it also says that is eight orders of magnitude less bright than the sun from the Earth. I'm not actually sure what he means by that, but Pluto is on average about 39 A.U. from the sun, while Earth is, of course, 1 A.U. If you take 240 full moons multiplied by 39², that makes 365,040. In fact the apparent brightness of the sun from the Earth is about 400,000 full moons, so that more or less comes out right.

[chris webster]

Greg Charles wrote:...it also says that is eight orders of magnitude less bright than the sun from the Earth. I'm not actually sure what he means by that...

(Apparent)Magnitude is a logarithmic scale for the relative apparent brightness of astronomical objects. Each step in the scale varies by a factor of around 2.512, and lower values are brighter. So a mag 2 star is roughly 2.512 times brighter than a mag 3 star. The numbers for objects in the solar system - like the sun or moon - are negative because these objects are so much brighter than the distant stars the scale was originally invented for (by the ancient Greeks).

[Guillermo Ishi]

Greg Charles wrote:
IANAA (I am not an astrophysicist), but I don't think you're representing that article correctly. Yes, it says that the apparent brightness of the sun from Pluto (at one particular point in its highly eccentric orbit) would be like 240 full moons, but it also says that is eight orders of magnitude less bright than the sun from the Earth.

Not sure what you think I misrepresented. For what I was originally talking about you have to go to a comment by one Mathias. Bob then endorses the comment.

[Bear Bibeault]

This is What Pluto and Charon Look Like in Real Life

[Campbell Ritchie]

But the animation of the fly‑past is annoying; it moves forwards for about 2″ and then snaps back to its original position, like optokinetic nystagmus.