How do we have the equipment to picture and see cosmos and stars millions of light years away, but can’t just zoom-in to examine and view the surfaces of our interplanetary planets in the solar system?
In: Physics
There’s a limit to how far you can “zoom in” on something to picture it. The maximum resolution is restricted by the wavelength of light used to capture the image. You can compensate by using a larger lens, but even the largest telescopes in the world aren’t anywhere near being large enough to have anything close to high-resolution photographs.
This question comes up when people ask why we can’t use a telescope to see the flag on the moon which is significantly closer than the planets but still very far away. Turns out just to identify that, you would need a telescope with a lens miles in diameter. If you want to look closely at planets, the lens would need to be larger than the diameter of Earth.
Now there are some neat tricks astronomers can use. Not too long ago, astronomers managed to take a picture of a black hole. The resolution to make this picture indeed would require a lens about the size of Earth, making it seem impossible at first. But what they did is synchronize a bunch of telescopes from all over the world then stitch the resulting data back together in software. Thus they were able to create a picture with sufficient resolution to identify what they were looking at. A similar technique could be used for getting some better precision for imaging other things as well, but it takes a lot of coordination and resources, and while it improves resolution, it still wouldn’t compare to sending over a probe with cameras to take pictures at a closer proximity.
We can?
I have an extremely high res picture of Pluto on my computer that takes up hundreds of gigabytes of space. In it I can zoom in to details the size of about a football field. And that’s not even the level of detail professional astronomers can achieve.
A better question is: why aren’t we creating tons of high res images of the planets and objects within our own solar system. And the answer to that is, we have and they aren’t really that interesting beyond the novelty of them.
We’ve been looking at all planets (not Pluto) in our own solar system with varying degrees of “zoom” for nearly 200 years. Most of them are visible with the naked eye, so magnification on even a small scale has produced some pretty good resolution. And to a certain point that was useful. But by the time your average enthusiast could see details of small craters on the moon with a couple hundred dollar set, we had gotten to the point where it was sort of pointless to be viewing the surface of local planets with super high powered telescopes. You can’t tell a lot of important features through a lens, no matter how powerful. So we started sending probes and rovers instead, and using/building those telescopes to view objects currently beyond our reach.
Imagine it this way: you have a nice telescope. You can use it to look at things very far away with some detail, things you are likely unfamiliar with. Or you can look at familiar things that are much closer with incredible detail (but still less detail than you would have from just being there).
Would you use the telescope to read the sign at the end of your street? Or would you use it to look at the moon and just walk to the sign if you want to read it?
The bottom line is that luminosity is tricky. A star 10,000 light years away may be far brighter than our sun, but the sun obviously appears brighter because it’s so close. We can see distant objects primarily because they are ridiculously bright and sending us their light from across the universe.
The next thing to consider, planets don’t emit their own light, they are reflecting the light from the sun. So while they are rather dim objects, they are close to us so they appear brighter than most stars in the night sky. And while we can actually see some pretty amazing detail of these planets with a telescope on the Earth, there’s still a lot we can’t see because it’s just too far away, but “zooming in” as it were, has its limits in the detail we can see.
Finally, stars from distant solar systems mostly just look like bright blobs, so while they are astoundingly bright, we don’t end up seeing much in the way of detail. Looking at distant galaxies are pretty cool too, but the detail we’re seeing in them is still limited because of distance. In an individual galaxy you can’t even really tell a single star, it’s just a swirly pattern, but the whole thing is made up of a billion billion stars so it’s altogether even brighter than the stars closer to us. The “detail” we supposedly see in distant galaxies is actually billions of stars making up this thing, this pattern.
So we actually can see better detail in the planets in our solar system, it just appears that we’re getting less detail compared to distant galaxies, but yeah, those things are huge, absolutely ginormous, so there appears to be greater detail, but it’s actually all more fuzzy, with individual stars not even discernable other than we know they are there.
Because stars and galaxies are SOOOOOO much bigger and brighter. They’re are literally many many times bigger than our sun in most cases, and those cosmic formations are light-years in size.
One’s a massive ball of nuclear explosions, the other is a big chunk of rock that reflects a bit of light.
Off topic…Why can’t we zoom in on bank robbers, store robbers, etc. ? For real, I’m tired of seeing blurred images of people committing crimes.
A better question would be why can’t we zoom and enhance with CCTV’s like in the movies when we can see stars millions of light-years away.
Wasnt there a post very similar to this a week or two ago….. That the limited resolution of the cameras was the same answer
Most of the high-resolution photos from deep space are of positively ***MASSIVE*** things that dwarf the imagination. Those photos aren’t snapshots, with quick lens openings. They involve leaving the lens open on the camera for hours, if not days. This allows for much more light to be captured, increasing resolution. However, if *anything* moved to any noticeable degree, it would be incredibly blurry because you’re capturing the light the whole time. The planets move too fast to even hope to zoom in like that.
The answer is why you can see a match a mile away on a dark night. The stars we see millions of miles away are smaller than individual pixels, but they are light sources. We are noticing the light they admit, how it changes, how they move, and so forth, but we aren’t making them ‘bigger’.
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