Why can’t we invent a telescope that zooms infinitely at perfect resolution to look at distant planets?
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Well, that telescope would have to be infinity sized to do such!
The biggest factors in a telescope ability to see are the size of its optics and the medium it’s seeing through. (There’s others but let’s stick to these important ones)
Bigger optics are better. And less “stuff” to see through is better. One reason space based telescopes are so useful is that land based telescopes have to see through the atmosphere which is nasty and turbulent, to get around that you move your telescope higher in altitude (such as placing telescopes on mountains in Hawaii or Chile) so there is less atmosphere to see through, atmosphere distorts the picture or better yet, how about in space where there is no atmosphere!
There are ways to correct some for the atmosphere and tricks to get smaller telescopes to perform better. But ultimately, bigger and less or no atmosphere is gonna be better.
You’re asking a huge question. The laws of physics, telescope aperture, accuracy of optical surfaces, diffraction, many aspects to the answer. Try reading this:
[https://www.cloudynights.com/documents/Understanding%20Resolution.pdf](https://www.cloudynights.com/documents/Understanding%20Resolution.pdf)
The finest, largest telescopes on Earth can’t resolve the Apollo lunar landing sites on the Moon. You use the word “infinitely”… an infinitely large telescope might let you do what you want, but that’s not realistic. They’re presently working on the ELT, the Extremely Large Telescope, which has an aperture of 39.3 meters, or 128 ft 11 inches. Telescopes can also be joined together to make what’s known as an interferometer, basically creating a telescope with an aperture of the distance between the two scopes. Timing between the two scopes must be very precisely monitored as the data from the scopes is married. The largest synthetic aperture interferometer on Earth is the Event Horizon Telescope, which marries radio telescopes around the world, basically creating a “telescope” with an aperture the same as the Earth’s diameter. The Event Horizon Telescope is what was used to image the supermassive black holes in M87 galaxy and at Sag A* in the center of our own galaxy. It took years and tons of computing power to compile the images. There’s talk of creating interferometers out in space, with huge separations between receivers. Still wouldn’t be “infinite”.
Dawes Limit ultimately governs resolution. It’s mentioned in the article linked above.
There are fundamental limits imposed by the laws of physics. Light has a property called diffraction, which means that when it passes through an aperture (like a telescope’s lens or mirror), it spreads out, limiting the ability to focus on extremely distant objects with perfect clarity.
Building larger telescopes can capture more light and provide better resolution, but there are practical limitations. Extremely large telescopes become prohibitively expensive and difficult to construct and maintain. The largest optical telescopes on Earth are already enormous, and building larger ones presents significant engineering challenges.
Earth’s atmosphere introduces distortions and turbulence that can blur the images obtained by telescopes. This is why many advanced telescopes are placed in space (like the Hubble Space Telescope) to avoid these atmospheric effects. Even in space, there are still some limitations.
Planets in our solar system are relatively close compared to stars in other galaxies. However, when we look at planets in distant solar systems (exoplanets), they are incredibly far away. Even with the best telescopes, the resolution might not be sufficient to see fine details on these distant planets.
No matter how advanced a telescope is, there’s a finite limit to the level of detail it can capture. This is due to factors like the size of the telescope’s primary mirror or lens, the wavelength of light being observed, and the inherent limits of optics.
Light waves have a finite wavelength, and this puts limits on how precisely we can observe distant objects.
To see an object with greater detail, we need a telescope with a larger aperture (which allows more light to enter) and a longer focal length (which magnifies the image). However, even the largest telescopes on Earth are limited by the turbulent atmosphere, which distorts the image and reduces the resolution.
Another limitation is the inherent fuzziness or blur that comes from the wave-like nature of light. This is called diffraction, and it makes it impossible to focus light perfectly. To overcome this limitation, astronomers use a technique called “adaptive optics” which involves measuring the distortions caused by the atmosphere and then correcting for them in real-time. However, this technique has its own limitations.
Finally, there are practical limitations to the size and weight of telescopes that can be launched into space. Even if we could build a telescope with perfect resolution and infinite zoom, it would not be feasible to launch such a massive instrument into orbit.
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