Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: grahamsteen on 28/02/2010 16:29:05
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we essentially see/study the universe from a single point of view: earth's orbit. I know, I know, the orbit itself is millions of miles in diameter. but cmon, millions of miles? thats nothing. we inhabit a single point in the universe. and we move a little.
would it be to our advantage to create space telescopes with galactic-stereoscopic vision?
that is to say, link two identical telescopes we place very, very far apart (and I'm talking REALLY far apart here). granted it would take a long time to collect any data... but would this not add another dimension to our visual understanding of the universe just as having two eyes has done for us?
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We do in effect do this. both by using the solar system and by using spacecraft. The earth's orbit provides parallax and the Hipparchus satellite did a classic set of measurements on thousands of stars using this source of stereoscopic vision. There is also a motion of the solar system around the galaxy and with care this can be used to reach further. There is also a pair of satellites called stereo that is generating stereoscopic images of the sun and spacecraft like this may be used in the future for other types of measurements. I am sure that the sending of a pair or even better a trio of powerful imaging telescopes with a long life into widely separated orbits out of the solar system will eventually be considered to enable detailed observations of very remote objects
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The starting point for measuring the distance to the stars and galaxies was via parallax.
The starting point was to take measurements of parallax, at opposite sides of the Earth's orbit around the Sun, which gives a parallax baseline of ~186 million miles, to enable us to directly measure the distance to a wide range of different star types. Once the different types of stars, and their properties (especially the Cepheid variables), had been established we could then use those properties (the properties of Cepheid variables) to establish the distances to the even more distant galaxies. After enough different galaxies had been surveyed we were then able to come up with yardsticks relating luminance to distance (for each type of galaxy) which then brings us up to Hubble's work, which established that the more distant a galaxy was from us, the more quickly it was receding from us.
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oh, good! while this forum is a fun and interesting place, it would be crazy ironic and sad if any truly revolutionary ideas came of it. (i think some people here think they're einstein incarnate... but shhh...)
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though, wouldn't it be amazing if the images that come back from whatever system we eventually deploy reveal an entire different picture of the universe that we've been missing all this time? i think it's entirely possible that that could be the case. maybe we've got every bit of it wrong...
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grahamsteen, we've tried to offer you our meager knowledge :)
Now it's time for you to really explain what you're expecting to come from your intergalactic observation posts? When it comes to what we can do it's very much as LeeE and SoulSurfer says. We are restricted by what we have in resources and ingenuity. If you f.ex have a better proposition, don't hesitate to put it forward for our titillation.
But we're trying Telescope the size of Earth (http://www.physorg.com/news151078629.html) :)
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when i said these people 'here' i didn't mean any disrespect to anyone in the thread. was just an attempt at humour in regard to some of the more ridiculous wall-of-text style novels that i've seen on the forum. as for my idea here, i was heartened by the fact that an idea that i thought was original has in fact been a standard in astronomy for a number of years, and has encouraged me to do a good deal more reading on the subject.
as for the original premise of my post, I simply meant to point out that what we've viewed so far of the universe is from a relatively fixed point in space, even if the diameter of our orbit is about 186 million miles, that is nothing on the cosmic scale of distances. i am essentially equating a 186 million mile ellipse to a single point in space.
my subsequent thought was to imagine that for all the work we've done with parallax so far, the difference simply is not enough. while it is almost useless to think of these things because it is impossible at present to prove otherwise, i imagined that perhaps several viewing devices separated by a great distance, maybe of a light year or so, could answer some significant questions.
like going from being able to only see a square to realizing it was a cube all along. i can't even begin to hypothesize what that view would entail, and i'm very probably wrong. but it was a thought i figured i'd share.
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A longer baseline would obviously be better, such as using Pluto, or one of Neptune's moons instead of the Earth, but there's the practical difficulty in getting the observation equipment there and set up correctly. In some ways it's a shame that the Voyager probes couldn't used for long baseline stuff, but then you've got to remember how much technology has advanced since they were launched and what seems relatively easy now was much more difficult even just twenty years ago, let alone when the Voyagers were sent up.