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-3

So this is really really easy and I don't know why the top answer doesn't explain what's going on. I have a lamp on my desk, which is opposite the headboard of my bed. Sometimes I lie there reading with the lamp on to illuminate the room, but with my lowered vantage point, oh no, a first world problem hits - there's a bright light in my field of vision ...


1

It's a combination of a few things. Firstly when we are looking for exo-planets we know we are not going to observe them based on their luminoscity, therefore we use different techniques based on how the exo planet will effect the light we observe from their sun. This method works brilliantly if the star and exoplanet are in relatively close proximity but ...


5

Pretty simple reason really. We only see exoplanets under extremely lucky circumstances. So we are only seeing a tiny tiny fraction of all exoplanets. If for example we are only seeing 0.1% of all exoplanets in each star system we look at, that is a HECK of a lot worse than the 8 out of 9 in our own star system.


23

The reason why we can see exoplanets 13,000 light years away but not a planet 200 AU away (about 30 light-hours) is because these planets are found using different techniques. The planet discussed in the article I linked was discovered using a technique known as "microlensing," which requires a star to pass behind another star with a planet around it. The ...


67

The problem with finding a new planet in our solar system is not that it is too faint, but knowing where to look in a big, big sky. This putative planet 9 is likely to be in the range 20-28th magnitude. This is faint (especially at the faint end), but certainly not out of reach of today's big telescopes. I understand that various parts of the sky are ...


6

We haven't detected planets millions of light years away. Right now the most distant is less than 20,000 light years away. Even for the planets we have detected, they are for the most part not "seen" or imaged directly. Instead they are found by the effect they have on the parent star (usually gravitational wobble or transit detection). In both cases, ...


0

You would most definitely use Kepler's third law. With almost all planets, the mass of the planet is negligible so it is ignored. We know the orbital period and the mass. Use those and Kepler's third law to write an equation for the orbital radius.



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