Outbound space probe looks back at tiny Earth and Moon NASA's space probe Juno, outward bound for Jupiter, has sent pack a pic of the Earth-Moon system from 6 million miles away. The Earth and Moon, seen from the Juno spacecraft 6 million miles out. Credit: NASA/JPL-Caltech I can see the pub from here According to NASA, Juno was further away than the Moon within a day of being …
What I don't know (and can't be arsed to find out quite frankly) is why NASA chose to limit the mission to solar power. What advantages does it hold? Considering the incredible expense and time it takes to put together a mission I would have thought they would want to wring every last drop of usefulness out of the probe.
Enquiring, yet lazy, minds want to know...
If it meets the needs of the mission then why not. The payload is to operate at a 2% duty cycle (from the article) so you can spend all that off time charging the batteries or caps or whatever. I would guess that the solar array is lighter than a nuke power plant and probably cheaper too.
In part it's a technology demonstrator that solar power can be used for deep space missions with low pier requirements, but in part it's been forced on the US by a lack of Pu-238 to go into radio thermal generators. The US has very limited supplies of the isotope which have to be shared between NASA and the military, and in recent years the US has been buying supplies from Russia. The US is ramping up production again, so this might only be a temporary bottleneck.
What tends to get forgotten in all the climate change debates is that climate change almost certainly won't destroy the planet, it *might* make it uninhabitable for *us* and a fair chunk of other "higher" lifeforms, but if we're wiped out by it then the planet and something like 90% of life will continue on quite happily - probably much more happily than it is at the moment.
Still, it'll finally put the Apple vs Android vs Samsung debates into perspective.
Yes, I think we should talk less about endangering 'the Earth' and more about endangering 'our civilisation's ability to continue'. Would drive the point in a bit better, considering average human self-centered-ness.
Of course the emphasis is on 'civilisation'. Even with catastrophic climate change there is a good chance a small portion of homosapiens would hang on at a subscistence level for hundreds of thousands of years. May even get back up to steam-power, but can't progress as all the readily accessible high-calorie fuels and 'rare' metals are long-since extracted and you can't get the rest without the boost that the easy stuff gave us.
So it very likely we have only once chance in the span of our species and if we blow it, many millions of years for the next opportunity (by which time homo sapiens is very unlikely to still be around, so some other species will be doing it by then).
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It could also be that all the "OMG NUKES! IT MIGHT CRASH ON TAKEOFF AND SPREAD RADIATION EVERYWHERE!!!!11" people caused NASA to think it'd just be easier to go solar and not deal with the protesters. I imagine it's also cheaper than having to build a small nuclear reactor and fuel it.
'cause I recall reading about the Voyager's last pic of the earth as it was heading past Jupiter/Saturn and it was coloured and described as a "pale blue dot". Look it up in Google, there is an interesting and moving story behind, it done by Carl Sagan's team. Or just start here: http://http:www.carlsagan.com
...not bad at all.
Now the zoom on Google Earth seems a triffle limiting.
Is there a laymans page that explains the mimimun dimension? Is it that dimensions quantize? If not then you can't have 1.5 times the minimum, becuase you can't say how much bigger than 1 it is, no?
Also why is the minimum / quanta so much smaller than any physical thing? Do the physical things move around on a grid of that size? or do they move around gridless, but if they get closer than that minimum then something weird happens?
After thinking about that, my worst case analysis has just got interesting again :)
space is quantized into units at the planck length apparently.
as for the notion that they can get closer than that, well, space and time cease to have meaning below that threshold because of the experimentally verified uncertainty principle, so any traditional definition of 'closeness' doesnt inherently make any sense.
as for how these minimum units of space are arranged (is it regular grid? a hexagonal grid? etc), this seems to fall into the same category. and at this scale extra dimensions from super-string theory might come into play anyway (if it turns out to be correct).
intuitive questions like -- "what happens when a particle emits a photon? shouldnt there be a fraction of time as it is being released when the photon is half in / half out, or half-formed?" -- dont necessarily make sense, as space-time is quantized, and the 'fraction of time' isnt something that can be said to exist in the real world on that scale.
Brian green has a decent section at the end of "The Fabric Of The Cosmos" about ideas that underpin space time.
Because of the vast difference in scale between gravitational strength and the planck length, it is extremely difficult to do experiments that probe how space-time (gravity / relativity / dimensions, etc) interact on a tiny scale.
What level of zoom is that camera using I wonder, to bring us that picture from 6 million miles.
Can someone answer why we can't see any other celestial bodies? Have they isolated Earth and the Moon somehow?
I'd rather see the heavens in their entirety, with Earth and the Moon highlighted.
But there was a discussion on space travel, and the gist of it was that if the Earth was the size of a basketball, the moon would be the size of a tennis ball 9 meters away. That was how far we traveled in the late 60s/early 70s.
Then if you take a ruler and measured 1cm from the surface of the basketball Earth, That's the ISS and how far we've been since then.
Sad, isn't it?
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It struck me as well, and as far as I can calculate, the picture doesn't even tell the full story. The orbit of the Moon places it either closer or farther away from the probe than Earth, so the full distance doesn't show.
The picture creeps me out actually. I know the distances and the scale of things in the universe, but they are so vast they become just numbers. That picture however is the closest thing to a total perspective vortex I have ever come (look it up). It is close enough that for brief moments my brain gets a little perspective, or dare I say "sense of proportion". And let me tell you, it doesn't like it at all.
Btw, I can see the Paris Hilton angle, but, well...
Now then, somebody mentioned a pub.
The gameplay... geez ...the freaking User's Manual is not in the box. The PvP flag is open all the time.
I won't even begin to complain about the GM apparent absence, abundance of PKs (that would be player-killers for the uninitiated), and general foul-play. Or heavy cheating and general, widespread abuse of the rules.
... trying to recompile the kernel will start a Flame War in a heartbeat. Specially without GM consent, no matter if you actually heard him telling you to do it, and you can't prove it to the other players.
... and the game takes freaking 9 months to download, and it takes 2 people already in the game to get you invited.
I 'll stop right now...
...already left the solar system and is still beeping back to Earth. Last I heard about it, anyway.
Radiation shouldn't be a concern (isn't it powered by plutonium?) and no micro meteors got hold of it yet.
This Juno thing heading to Jupiter should have no problems.
Voyager holds right now the most range covered by a human-made working device, I guess. And I also guess you can count the distance to it light-hours or light-days, or a small percentage of a light-year. Pluto for instance is 4 light-hours away.
These distances are enornous, eh?
I once looked at the moon across a plateau, with it hung low in the sky. I could grasp the distance and actually feel it was close by.
I've driven the 200,000 miles to the moon, and back. OK, it took 20 years on and off, but it's not that far. At the time, I could even see the possibility of a space highway going to the moon.
But, where Juno is, and looking back, that's a different matter altogether. Does not compute!
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