Nemesis, Tyche, and/or the Hills Cloud Super-Earths: Real or unreal?

[cantab]

Everything gives off heat. Maybe not a lot, but everything gives off some. In the absence of the Sun, Earth's internal heat flux would warm it to around 35 K (depending somewhat on the surface albedo), and its emissions would peak around 80 microns in the far infrared. Various space telescopes have been capable of observing such wavelengths though I don't know if any were large enough to detect such a planet.

Figures from messing around here http://www.spectralcalc.com/blackbody_calculator/blackbody.php

[AngelLestat]

If there was a Mars or Earth sized planet out in the Oort cloud covered in coal black dust and not giving off heat, what type of equipment could detect it?

If you know where it is, then it will be possible to detect it.

But the problem is that we dont. So it can be an earth size planet at 1000au with the same albedo than earth or more; but almost impossible to discover.

The sun at that distance is like any other star, imagine the few photons that reach the planet, then imagine the few photons that bounce and comeback to earth.

Is a lot easier to search planets in other stars, first you know where they can be... "close to the star"

With the transit method, the planet is so close to the star that it block a lot of photons when this pass upon.

The second method using telescopes, you measure the tiny gravity wobble from the star.

Here you dont have any of those benefics.

As cantab said you have more chances to detect heat radiation, but even with that, you would need point at a very specific direction with an IR telescope in orbit (they can work close to 4 kevins degrees which gives a lot more sensibility)

You can not use the picture-picture comparition with high or moderate angle of arch as we do with asteroids, because this planet moves so slow as any other star in the sky.

And if you use the IR telescope to scan all the sky, it may take centuries to find it.

[Duxwing]

If we really were lazy we could just send a Project-Orion-eqsue probe out there in just a few years.

Of course though this would require a repeal of the Partial Test Ban treaty.

Three cheers for Ol' Boom-Boom! A nuclear pulse drive, especially one launched from a graphite barge in the Arctic, would enable missions well-worth their risk and expense.

-Duxwing

Edited January 21, 2015 by Duxwing

[Tommygun]

Thanks guys, I was thinking it would come down to knowing where to look, the Oort cloud is a big place to fully survey at high resolutions.

I'm surprised they can't measure the Sun's wobble from Earth to confirm the number of known orbiting objects with any unexplained influences.

[Bill Phil]

Thanks guys, I was thinking it would come down to knowing where to look, the Oort cloud is a big place to fully survey at high resolutions.

I'm surprised they can't measure the Sun's wobble from Earth to confirm the number of known orbiting objects with any unexplained influences.

Jupiter and the other gas (really fluid) giants have so much mass that the barycenter of the solar system isn't within the sun. So, measuring the sun's wobble wouldn't work that well, the margins for objects that are very far out are tiny, even massive ones.

[Jovus]

At around 6 arcseconds, I wouldn't really trust WISE to notice individual planets at 1000 AU. Not that it can't, but that nondetection isn't definitive, I wouldn't think.

[daniel l.]

Even if one exists, we'll never go there until we get FTL. If at all. So it matters little.

Actually quantum vaccuum engines can get you there in less than 10 years

[Bill Phil]

Actually quantum vaccuum engines can get you there in less than 10 years

Barring cheats...

[Whirligig Girl]

Here's the thing:

Our Sun has a SoI that's pretty large. However, if you're any further than about a light-year out, it is very difficult for a smaller body to orbit the Sun consistently and for long periods of time.

This is because the SoI of objects doesn't work quite like it does in KSP. Instead of having only one object pulling on any given space rock, there are many different objects exerting their gravitational pull. Some of them would have a larger amount of pull than others.

Now, consider a space rock orbiting at about 1 AU.

A star, with about one solar mass, passes by our Sun at a distance of 2 AU. This is far from unusual: Our sun has many celestial neighbors, and they sometimes get rather close. And, after all, this planet has spent four billion years out there.

As the star passes, nobody really cares very much. Any inner planets are deep inside the Sun's gravity well. Their orbits will change very, very subtly, but it's no cause for alarm.

That outer planet, though? If it gets too close to that star, its orbit will be significantly disturbed. It may enter a highly elliptical trajectory around our Sun, it may be ejected from our Solar System, or it may even fall into orbit around the other star, if it's lucky.

Saying that such a planet could remain in orbit around our Sun for billions of years, on a relatively undisturbed path? That's a little unlikely.

...and saying that things could orbit the Sun if they were anywhere in the Sun's sphere of influence makes me think that you're subscribing a bit too much to the simpler physics of KSP. Not that there's anything wrong with KSP... it's just that the real world is a bit different.

I'm just going to guess you mean 20 or 200 AU. 2 AU is closer than Jupiter.

Anyway, I was writing a short-ish sci-fi story about Tyche, a brown dwarf, nearing the solar system during the 1950s to the 1970s, and both NASA and the ROSCOSMOS recognized that this would be a very very rare event. Soviets develop an Orion Nuclear Pulse Rocket, while the Americans build fleets of Nova Rockets to assemble a spacecraft in orbit. The latter launches in 1969, the day before the Apollo spacecraft landed. THe former is late in construction, and is only launched in 1975. But the Americans are much slower to reach the target, using flybys of Jupiter and to some small extent the edge of Saturn to reach Tyche at as low a relative velocity as possible before it's too late. The Russians however, boost their Orion NukePulser so fast that they reach Tyche only 3 months before the Americans.

[PB666]

Wow, no one's reading this thread.

no one's my nick, how did you guess.

- - - Updated - - -

Barring cheats...

let's start that thread up again!!!!! (not)

[PB666]

Jupiter and the other gas (really fluid) giants have so much mass that the barycenter of the solar system isn't within the sun. So, measuring the sun's wobble wouldn't work that well, the margins for objects that are very far out are tiny, even massive ones.

Doing some sloppy math here if the earth has a period of a year and is 8 lm from the sun and object X is 1 ly from the sun (the object is roughly 67,000 AU from the sun) then its period would be T_P(earth) * 67,000^3/2 or 16000000 yrs (+/- a Planck's time unit). So if our precise astrological observations of the sun and objects nearby have been ongoning for say 400 years roughly the sun has wobble 1/100th of a degree or 1/6000th of a radian during that time.

Lets start with that object within the Oort cloud, it would have cleansed the local area of mass, but their might also be Trojan comets at +/- 120' and 180 that act as balancers and all kinds of mass interior to the object in the Oort cloud. We can top that off with the fact that if there is 1 object that size there are probably other objects that are smaller, so then you have to consider the probability that these might have a balancing effect, in which case the wobble may not be directional to the object particularly when we factor in the contributions of Jupiter, Saturn and the two outer planets.

Also, we don't know the gravitational constant securely past the 4th digit, which means we also do not know the suns mass to also beyond the 4th digit, our solar system is also is an incalculably complex N-body problem, other objects in the vicinity of the sun also pull on the sun. And the inner solar system objects are so close to the sun and there are so many unknown inter-actors (asteroids and the like) and given the underlying variable definition problems, the mass issues is not the only problem . . . . . . . . . .

The point is that it would be difficult to distinguish a tiny wobble anomaly in the sun's historical motion from anomaly from all other possible sources mindful of the mass, but weighing more heavily the orbital period.

Note if you did not catch the joke about the Planck's time unit .... go bang your head against a tomato 6 times.

[Astrofox]

Considering that we don't know too much about our place in space, I guess that there MAY BE something out there, but it probably won't collide with the Earth and instead will be in a near circular orbit (the gravity of all masses in the solar system would have little effect on something that is a couple thousand AU away), so therefore we won't know until we have the strong technology of a highly advanced telescope. But until then we will only make assumptions and guesses.

[YNM]

The point isn't about resolution - the point is on the limiting magnitude and the correct wavelength (which is around IR-NIR for these objects). You don't need to resolve a star (AFAIK there're no star resolved truly beyond a dot (so saturation don't count) yet) to know there's a star - you only need to catch enough photons from that star to intensify the signal. Same goes for asteroids and even, comets.

My belief would be on near-passing dim brown dwarves in the past or future. The latest known nearest passing (<1 ly ! Compare that to Proxima's 4 ly or Oort cloud's ~1 ly radius) star in the past (70000 yr ago !) was found at a fair distance from us, and a fairly faint magnitude - yet most observer doesn't seriously consider these kind of stars ! Maybe wait for Gaia for an automated one...

Or maybe the PIDM-disk hypothesis is correct... Or maybe it's purely only Sun's orbit wobble wrt the Galactic plane (enter it, leave, return again, leave).

Edited March 12, 2015 by YNM

[Albert VDS]

A better question, than asking if Nemesis, Nimbiru or planet X exist, is if it's even possible a planet can be formed inbetween the Kuiper Belt and Oort Cloud.

By planet I mean something bigger than Mercury. Would the bigger orbital path create more space between objects when they form into asteroid/plutoids?

What about the orbital speed? Would it make it harder for planets to form?

[maltesh]

Also, we don't know the gravitational constant securely past the 4th digit, which means we also do not know the suns mass to also beyond the 4th digit,

. In all the math that's used to work out gravitational effects, it's the Gravitational Parameter of the Sun that's used, and that's been measured to 12 significant figures.