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A dwarf planet coming within 11 AU of the sun over the next 10 years
141–150 of 330 posts
Re: A dwarf planet coming within 11 AU of the sun over the next 10 years
#142I know very little about the subject, but does this mean that there are planet-sized objects in orbit around the sun of which we are unaware of?
There definitely are. A major reason for "demoting" Pluto was there are more such Pluto-scale planets in the Kuiper belt. Maybe we will find one bigger than Pluto.
Thanks! That's wild to me. All talk about exoplanets and other pop-sci headlines makes you think we would have our own backyard figured out. Then again, I suppose the vastness of space is vast even within our solar system.
Re: A dwarf planet coming within 11 AU of the sun over the next 10 years
#143Earlier quoted context omitted.
Let's send some boosters out there, redirect it to earth, and make a second moon. Come on people, what ever happened to doing shit cause its fuckin' rad, do you know how cool another moon would be?!
Constructive interference from multiple tidal waves could flood huge coastal areas, killing or displacing millions. Uncool.
Or very cool if you're an evil villain in a movie/comic. Give me one milllllion dollars, or I will bring in a second moon!
Re: A dwarf planet coming within 11 AU of the sun over the next 10 years
#144Earlier quoted context omitted.
> The presence of natural satellites indicates this can indeed happen No, it doesn't, because natural satellites are generally not captured, and for those that are captured, the process involves interactions with other bodies.
The first hit when I search "planets capturing moons" says natural satellites generally are captured. "Most satellites of the outer solar system didn’t form with their host planets" https://astronomy.com/news/2016/12/captured-moons-of-the-gia... Even Triton, which is the size of a planet and in an almost circular orbit, is thought to be captured, the last I heard.
Jupiter’s moons are I’m harmonic orbits because they trade momentum until they balance out.
From what I understand any eccentric orbits would either flatten out or crash into Jupiter.
Re: A dwarf planet coming within 11 AU of the sun over the next 10 years
#145Earlier quoted context omitted.
It's an old unit, so there wasn't a global standard yet, and it's exact value wasn't known for a long time, but it was still useful for ratios. E.g. if you observe the orbit time of another planet, you can tell its distance from the sun relative to the distance of Earth to Sun (1 astronomical unit) relatively accurately, even if you can't measure what it is in meters very well.
For my purposes 10 AU has a lot more meaning than 1 billion km. 1 AU has a lot more context
It's one of those things that I still tilt my head slightly at when thinking about how the human brain struggles with really large numbers. Its just an odd thing.
Re: A dwarf planet coming within 11 AU of the sun over the next 10 years
#146Earlier quoted context omitted.
Getting into orbit would be rather difficult, as the probe would have have to match the planets velocity at perihelion. My instinct says it’s probably just on the edge of doable (although I’m not sure on which side), but I haven’t crunched the numbers. It would almost certainly need to be launched on a Delta-IV or Falcon Heavy class vehicle. EDIT: s/perigee/perihelion. I could say periapse and be neutral, but perihel…
In a few years, can't we look forward to SpaceX making it routine to refuel in orbit? If we assume that's feasible, I wonder what sort of missions it would enable, other than human spaceflight.
Hopefully yes. I was being conservative with my suggestions.
Re: A dwarf planet coming within 11 AU of the sun over the next 10 years
#147Earlier quoted context omitted.
Let's send some boosters out there, redirect it to earth, and make a second moon. Come on people, what ever happened to doing shit cause its fuckin' rad, do you know how cool another moon would be?!
Constructive interference from multiple tidal waves could flood huge coastal areas, killing or displacing millions. Uncool.
Then again, global warming is going to flood huge coastal areas, killing or displacing millions, which is a pretty uncool thing we're doing to ourselves, so maybe Second Moon will counter-act that? There's literally no way of knowing until we try. And worst case scenario, we ruin a bunch of earth and we've got a second moon to move to. Its a win-win.
Re: A dwarf planet coming within 11 AU of the sun over the next 10 years
#148Earlier quoted context omitted.
It can reduce the delta-V requirements, though - by the same principles as a gravity assist, a capture burn (especially into a loosely-bound planet-centric orbit) often takes less work than burning into the equivalent heliocentric orbit on your own.
Right! The Oberth effect for a smaller body is not as large as it would be for earth, but would still be non-zero.
"Non-zero" is the key word here.
Oberth effect from fast flyby of a body with low gravity would be negligible.
Re: A dwarf planet coming within 11 AU of the sun over the next 10 years
#149Earlier quoted context omitted.
It can reduce the delta-V requirements, though - by the same principles as a gravity assist, a capture burn (especially into a loosely-bound planet-centric orbit) often takes less work than burning into the equivalent heliocentric orbit on your own.
> by the same principles as a gravity assist, a capture burn Note to the audience: these mechanisms don’t violate the conservation of energy because you aren’t tapping the object’s gravitational energy per se but instead its orbital energy around the sun. Put another way, you can’t do a gravity assist or capture burn in any direction.
The usual way I explain it is as a transfer of kinetic energy and momentum from the large body to the small one. The interaction is through gravity, rather than the mix of electrostatic, degeneracy, and strong/weak forces involved in collisions; but the equations are more or less the same.
(Usually textbooks use a baseball bouncing off a semi truck to illustrate.)
Re: A dwarf planet coming within 11 AU of the sun over the next 10 years
#150Earlier quoted context omitted.
It can reduce the delta-V requirements, though - by the same principles as a gravity assist, a capture burn (especially into a loosely-bound planet-centric orbit) often takes less work than burning into the equivalent heliocentric orbit on your own.
Ok, good point. Thanks.
Still definitely not worth it for something so small, though!