Pandora
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« on: July 15, 2011, 10:57:32 AM » |
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How come we cannot see the smallest details of the planets and moons in our own solar system without sending probes. If we can see so detailed photos of the great pillars then we should be able to see an ant butt on Saturn without probes. And now based on the wobble of other stars we now think we see other planets around those stars and determine that life might be there. I just wonder if we really know facts or if most are theories. What are the standards used to govern these findings other than bands of light?
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Kowalski
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« Reply #1 on: July 16, 2011, 01:57:14 PM » |
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Confucius say, a mountain is easier to see then an ant at the same distance.
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GeoffG
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« Reply #2 on: July 16, 2011, 08:45:42 PM » |
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It is a question of angular resolution. Even though they are close to us, the planets are very small in angular size, so that fine detail is beyond the resolution of the largest telescopes. To use your own example, the Eagle Nebula ("the pillars of creation") fills the field of the lowest power eyepiece in my telescope, whereas Saturn is still tiny even at the highest magnification I have available. I was looking at both these objects two nights ago, and the difference was amazing!
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William_E
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« Reply #3 on: July 17, 2011, 08:20:49 PM » |
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Good question!
Fact is, it can be done and has been done, only seeing a shape and seeing below its atmosphere are two different situations, requiring a different approach.
Proximity detectors can probe for wavelengths with clarity where fixed devices a thousand times more powerful could not dream.
Would it make matters better, if you had a million times magnification lens pointing at an object behind a brick, when you could just remove the brick and look at it? No amount of optical magnification would suffice if the brick was impermeable to light within the visual spectrum.
(GeoffG) is also correct.
This is a case of photon separation, where as we get closer, we see more exponentially. This is due to the spreading of the light from the source, but in a straight line, hence (angular resolution). Its like when you are thrown three spheres, the spheres, unless thrown off in exactly the same direction, will separate in the direction of their trajectory. If someone throws these three spheres to you from close proximity, you will have a good chance of catching them and seeing them, as they have little time to separate and go of in their unique direction, or out of sight. If however you are 50 meters away, separation would have you running after each one. If we were a mile away, we may only ever see one sphere! As we can’t move that fast, we can’t catch all these photons or otherwise electromagnetic emissions. This, because our telescopes are fixed and relatively stationary.
Though why we don’t have access to images of the footprint on the moon is seriously beyond me! Though (Morningfox) has just answered that one!
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Morningfox
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« Reply #4 on: July 17, 2011, 08:45:58 PM » |
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Light and a few neutrinos, plus a few cosmic rays and the occasional rock or dust, are all we get from space.
The best telescopes can resolve 0.01 arcseconds in visible light. At the distance of Mars, that works out to 3.8 kilometers; that's a pretty large ant butt! In order to see anything smaller, we need to send those probes to get closer.
The Pillars of Creation are about 7000 light years away. The smallest detail that we can see in visible light is about 21.5 AU (3.2 billion km). And that's just one pixel.
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goring
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« Reply #5 on: July 17, 2011, 09:24:23 PM » |
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The Reason is relativity. The further away an observer on Earth is from a celestial body ,the more the body appears to contract and by the same token its motion appears very slow ,hence time appear longer than it actually is.
If an observer sitting at the edge of the Universe was to view the house you live in, it would appear so microscopic that the details would be a tiny dot. And if you stepped out the door to get your mail, to the observer it would seem that you took 13.7 billion years to get to the mail box.
That is what Einstein called Time dilation.
The earth was uniquely designed to support biological life while moving inside the milky way. There are another one trillion galaxies besides the milky way. and we have not seen any thing like the Earth.
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J__Douglas_Wolfe
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« Reply #6 on: July 17, 2011, 10:12:51 PM » |
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>>>...If we can see other stars, galaxies and to the edge of the universe...>>>
It is NOT true that we can see to the edge of the universe. It is entirely possible that the universe does not have an edge.
>>>...How come we cannot see the smallest details of the planets and moons in our own solar system without sending probes...>>>
Many reasons. One is that the earth's atmosphere blurs the image when we look through it. Spacecraft do not have to deal with looking through our atmosphere.
>>>....If we can see so detailed photos of the great pillars then we should be able to see an ant butt on Saturn...>>>
The so-called 'pillars' are a famous picture taken by the Space Telescope. Again, the Space Telescope does not have to deal with looking through the armosphere.
>>>...based on the wobble of other stars we now think we see other planets around those stars...>>>
We have never 'seen' these planets. Their wobble has been detected using a process quite different from what the human eye does.
>>>... and determine that life might be there...>>>
No scientist has said that there is life there, because there is no data to indicate life.
>>>...What are the standards used to govern these findings other than bands of light?..>>>
Many of these discoveries have been made using wavelengths of electro-magnetic radiation other than visible light. These wavelengths are useful tools, but they are not the same as what we usually mean when we talk about what something 'looks like.' We can detect them with lab instruments, but that is not the same as 'seeing' them. When a writer says we 'see' these things, it is a metaphor.
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