Viewing a single comment thread. View all comments

Always2ndB3ST OP t1_jd58ak8 wrote

Reply to comment by reddit455 in Is there another massive planet beyond Neptune? If so, why haven’t we found it? by Always2ndB3ST

Sure it’s a gigantic area, but my logic was that we are discovering exoplanets left and right. Why is it so harder in our own backyard?

−3

UrsusRomanus t1_jd596gh wrote

We discover exoplanets because they are little black dots in front of a giant field of light.

Finding another planet past Neptune would be looking for a tiny black dot in front of a giant field of black.

15

TorontoCorsair t1_jd5fk2c wrote

This.

Exoplanet hunting is significantly easier because of this. We also know where to look because each star acts as a beacon indicating that there may be planets and the field of view required for detection is minimal. We don't really need to calculate where they may be, we just have to observe in one small spot of the sky for a bit of time and see if the brightness level changes.

Trying to detect another planet around our own sun we could potentially calculate for, but even trying to observe it may be incredibly difficult as it could be a very dark object that doesn't radiate much of anything and if it is passed neptune it is barely receiving any light from our sun. Add in that it technically could be anywhere within sky, more realistically within the 17 degrees all other planets of the sky are within, we still would have to look over huge swaths of the sky to try and find it. A most difficult task indeed.

5

sifuyee t1_jd5h5q4 wrote

And most of the Exoplanets are actually found by observing the small doppler (color) shift of the parent star light as the planet tugs the star towards us then away from us, which is why most of the planets found so far are close to their parent stars (means we can find the color/doppler shift with shorter observation times). Since this object would be beyond the orbit of Neptune, its orbit period is longer, thus one would have to make very precise observations over baselines of a century or so to see the signal start to show up in solar observations. We might just be getting close to that threshold now though if someone wanted to try to compile the last century of data and try to correct for all the instrument bias and other sources from the rest of the known solar system. That would only give us the general orbit period and distance though.

3

otatop t1_jd5aw5x wrote

> we are discovering exoplanets left and right. Why is it so order in our own backyard?

Discovering exoplanets is sort of like seeing distant mountains, we can spot them because they're "easy" to find by just looking for dips in light from their respective stars.

Discovering a planet near us is like being able to identify a small pebble from far away because we can't use the same methods we use to find exoplanets, so we're just blindly looking into space trying to see if one of the millions of little dots we can see moves like a planet would.

2

Designer-Wolverine47 t1_jd5fypy wrote

One way would be to send out two observatories in perpendicular directions then at a sufficient(?) distance, have them look back at the sun and look for unexpected perturbations. Then calculate.

It wouldn't be cheap though...

0

cantwejustbefiends t1_jd5khps wrote

With this object being so far away, and a possible 10,000 year orbit, it would take a long long long time to make out perturbations due to it.

2

reddit455 t1_jd5hfj0 wrote

there's a lot of stars with planets. you want to find ONE PLANET.

​

>Why is it so order in our own backyard?

this covers a patch of sky the size of your thumbnail held at arms length. 10,000 galaxies, each with tens of millions of stars... each of those stars with planets.

​

The Hubble Ultra-Deep Field (HUDF) is a deep-field image of a small region of space in the constellation Fornax, containing an estimated 10,000 galaxies.

https://en.wikipedia.org/wiki/Hubble_Ultra-Deep_Field

​

this covers a patch of sky the size of a grain of sand held at arms length

NASA’s Webb Delivers Deepest Infrared Image of Universe Yet
https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-delivers-deepest-infrared-image-of-universe-yet/

NASA’s James Webb Space Telescope has delivered the deepest and sharpest infrared image of the distant universe so far. Webb’s First Deep Field is galaxy cluster SMACS 0723, and it is teeming with thousands of galaxies – including the faintest objects ever observed in the infrared.

1

Always2ndB3ST OP t1_jd5p81w wrote

Man, the incomprehensible size of space never ceases to amaze me..

1