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New Horizons
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Ace Attorney wrote: »Neil degrasse Tyson, Man is a legend. Humble and a very likeable person.
This traitor?
Wash your mouth out with soap!
https://youtu.be/_oxGy7zN7bs0 -
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Curly Judge wrote: »
There's an inspiring little short film, about 15 minutes long, called Naming Pluto. I think it's still available to buy online. They talk to Venetia Burney and show her talking to local school kids in Banstead, Surrey where she lived (down the road from my sis'). Was made in '08, the year before she died. She's also shown talking to Patrick Moore, and visiting a telescope in the south of England where they showed her Pluto in the flesh. And of course, they were talking about New Horizons which had been launched two years before.
EDIT: clip here ...
https://www.youtube.com/watch?v=Y6D9AQuB3QU0 -
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Mosaic of the 2 LORRI pics released so far for Pluto:
NASA / JPL / JHUAPL / SwRI / Emily Lakdawalla
Sources0 -
Those pictures reminded me about the statement I've seen printed that "the Sun looks like just another star from Pluto". Yet we've got clear shadows of mountains and crater rims. I realise that the contrast is probably enhanced many times, but I still doubt you could do that by ordinary starlight.
It turns out that the Sun looks like another star only in the sense that it is too small to be resolved into a visible disc by the human eye most of the time from Pluto. At it's closest to the Sun, it appears about same size as Venus does from Earth, which is considered to be just at the limit of human resolution (about one arcminute).
The comparison ends there, though. Depending on time of Plutonian year, the Sun would be 150 to 450 times as bright as a terrestrial full moon. Your surroundings would be lit as brightly as inside an electrically lit room on Earth. Yes, it would be one or two thousand times dimmer than a sunlit day on Earth, but the eye compensates quite easily. (I'm always tickled by the factoid that when you read a book in bright sunlight, the black print on the page is brighter than the white page itself is under electric light).
Another interesting point is that while the Sun's luminosity decreases with the square of the distance from it, so does the apparent area of the solar disc. This means that the brightness per unit area of the disc is constant. So you can simulate the Sun on Pluto by looking at it from Earth through a one millimetre hole cut in, say, metal foil and held at a distance of one metre. Of course, you'd have to block out all extraneous light, so you'd have to be inside a completely darkened room while doing it.
EDIT: It occurs to me that it's not quite a fair comparison. On earth, about 16% of the visible sunlight is not coming to you from the sun's disc at all, but in diffuse form from the sky. Above the atmosphere, that 16% of scattered light would be added to the direct light from the sun, plus another 8% or so that doesn't make it through the earth's atmosphere at all, so the sun is quite a bit more intense (and less yellow). So maybe you need to make the hole 1.12 mm to increase its area by 25%. Then again, the 1 mm was a rough guesstimate to being with, so I'm splitting hairs.
(Sources: 1, 2)
Here's the relative size of the Sun seen from different bodies in the Solar System. From the Earth it is half a degree, or 30 arcminutes:
On my screen, that solar disc from Earth is about 3.5 cm across. That means you'd have to stand 4 metres from the screen to see the correct angular sizes. (Just multiply the width on your screen by 720). I did a very unscientific test, and stood roughly 4 metres from the screen. Although I could still see the Pluto disc, I was seeing the black circle around it whereas I think the solar disc is supposed to be the area enclosed by it. The perception of a circular area enclosed by the black surround did indeed disappear somewhere between 3 and 4 metres distance.0 -
Those pictures reminded me about the statement I've seen printed that "the Sun looks like just another star from Pluto". Yet we've got clear shadows of mountains and crater rims. I realise that the contrast is probably enhanced many times, but I still doubt you could do that by ordinary starlight.
It turns out that the Sun looks like another star only in the sense that it is too small to be resolved into a visible disc by the human eye most of the time from Pluto. At it's closest to the Sun, it appears about same size as Venus does from Earth, which is considered to be just at the limit of human resolution (about one arcminute).
The comparison ends there, though. Depending on time of Plutonian year, the Sun would be 150 to 450 times as bright as a terrestrial full moon. Your surroundings would be lit as brightly as inside an electrically lit room on Earth. Yes, it would be one or two thousand times dimmer than a sunlit day on Earth, but the eye compensates quite easily. (I'm always tickled by the factoid that when you read a book in bright sunlight, the black print on the page is brighter than the white page itself is under electric light).
Another interesting point is that while the Sun's luminosity decreases with the square of the distance from it, so does the apparent area of the solar disc. This means that the brightness per unit area of the disc is constant. So you can simulate the Sun on Pluto by looking at it from Earth through a one millimetre hole cut in, say, metal foil and held at a distance of one metre. Of course, you'd have to block out all extraneous light, so you'd have to be inside a completely darkened room while doing it.
(Sources: 1, 2)
Here's the relative size of the Sun seen from different bodies in the Solar System. From the Earth it is half a degree, or 30 arcminutes:
On my screen, that solar disc from Earth is about 3.5 cm across. That means you'd have to stand 4 metres from the screen to see the correct angular sizes. (Just multiply the width on your screen by 720). I did a very unscientific test, and stood roughly 4 metres from the screen. Although I could still see the Pluto disc, I was seeing the black circle around it whereas I think the solar disc is supposed to be the area enclosed by it. The perception of a circular area enclosed by the black surround did indeed disappear somewhere between 3 and 4 metres distance.
Great stuff ps.
Keep them coming.0 -
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Stunning nightside view of Pluto! Speeding away from the dwarf planet just seven hours after its July 14 #PlutoFlyby, our New Horizons spacecraft looked back and captured this spectacular image of Pluto’s atmosphere, backlit by the sun. The image reveals layers of haze that are several times higher than scientists predicted. Details: http://go.nasa.gov/1SGfx0i
http://www.nasa.gov/feature/stunning-nightside-image-reveals-pluto-s-hazy-skies0 -
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Curly Judge wrote: »
The complexity of this surface is stunning.
They'll be years sorting it out.
mountains on icesheets by the looks of it crazy.0 -
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