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Proxima Centauri is about 4.24ly away and has a mass of about 0.12x the mass of the sun. I think that means our sun is the object with the deepest gravity well

Proxima Centauri is about 4.24ly away and has a mass of about 0.12x the mass of the sun. I think that means our sun is the object with the deepest gravity well, out to about (1/1.12)*4.24 = 3.79ly away. I think that means that there could plausibly be objects out to about 3.79ly away that are in orbit around our sun. The object from the article is about 0.0019ly away, so there could be quite a lot of new most-distant solar system objects still to be discovered!

gammateam 8y ago
Thats an interesting way to think about things I had always thought of the solar system ending with the planets with some ambiguity about the ort cloud But thinking about it as a system influenced by the biggest gravity well makes a lot more sense
Thorondor 8y ago
You're ignoring Alpha Centauri A and B, which are much larger. Also, even without the Alpha Centauri system, very distant orbits (more than 2-3 ly or so) would be destabilized by the galactic tide, i.e. the gravitational gradient of the Milky Way galaxy.
XaspR8d 8y ago
Some estimates for the outer boundary of the Oort Cloud put it at 200,000AU = 3.16ly (more conservative estimates seem to be 1ly or less). Even the inner boundary is thought to be at least double the distance of the object just discovered, so current astonomical hypotheses align with your idea that there's a lot more out there.
- jstanley 8y ago
  Given Thorondor's sibling comment to yours: Alpha Centauri A has a mass of 1.1x the sun, and is about 4.37ly away, which would mean our sun's gravity well runs out at (1/2.1)*4.37 = 2.08ly - i.e. any object in orbit 2.08 ly away would (even if affected by nothing else), fall into Alpha Centauri A's gravity well before completing a full orbit and therefore couldn't possibly remain in orbit around our sun. If that's true (and I have no idea whether any of it is true), then I think 2.08ly must be an upper bound on the outer boundary of the Oort cloud. EDIT: Ah, I'm thinking 2-dimensionally. Of course, something could be in a much larger orbit in a plane that doesn't go near Alpha Centauri.
- misthop 8y ago
  I think the hypothesized inner boundary of the Oort cloud is 2,000 AU[0] making it 20x the distance as this new object, not double. [0]https://en.wikipedia.org/wiki/Oort_cloud https://en.wikipedia.org/wiki/Oort_cloud
hyperpape 8y ago
While it's currently closer, "The Goblin" has an aphelion of 1955 AU: https://en.wikipedia.org/wiki/2015_TG387 https://en.wikipedia.org/wiki/2015_TG387. That's still only .03 ly, but we already know about objects whose orbits go much further.
phkahler 8y ago
>> The object from the article is about 0.0019ly away, so there could be quite a lot of new most-distant solar system objects still to be discovered! And yet, Voyager 1 and 2 have now "left the solar system" and entered interstellar space. It looks to me like the definition of what's part of the solar system is a bit squishy.

gammateam 8y ago

Thats an interesting way to think about things I had always thought of the solar system ending with the planets with some ambiguity about the ort cloud But thinking about it as a system influenced by the biggest gravity well makes a lot more sense

Thorondor 8y ago

You're ignoring Alpha Centauri A and B, which are much larger. Also, even without the Alpha Centauri system, very distant orbits (more than 2-3 ly or so) would be destabilized by the galactic tide, i.e. the gravitational gradient of the Milky Way galaxy.

XaspR8d 8y ago

Some estimates for the outer boundary of the Oort Cloud put it at 200,000AU = 3.16ly (more conservative estimates seem to be 1ly or less). Even the inner boundary is thought to be at least double the distance of the object just discovered, so current astonomical hypotheses align with your idea that there's a lot more out there.

jstanley 8y ago
Given Thorondor's sibling comment to yours: Alpha Centauri A has a mass of 1.1x the sun, and is about 4.37ly away, which would mean our sun's gravity well runs out at (1/2.1)*4.37 = 2.08ly - i.e. any object in orbit 2.08 ly away would (even if affected by nothing else), fall into Alpha Centauri A's gravity well before completing a full orbit and therefore couldn't possibly remain in orbit around our sun. If that's true (and I have no idea whether any of it is true), then I think 2.08ly must be an upper bound on the outer boundary of the Oort cloud. EDIT: Ah, I'm thinking 2-dimensionally. Of course, something could be in a much larger orbit in a plane that doesn't go near Alpha Centauri.
misthop 8y ago
I think the hypothesized inner boundary of the Oort cloud is 2,000 AU[0] making it 20x the distance as this new object, not double. [0]https://en.wikipedia.org/wiki/Oort_cloud https://en.wikipedia.org/wiki/Oort_cloud

hyperpape 8y ago

While it's currently closer, "The Goblin" has an aphelion of 1955 AU: https://en.wikipedia.org/wiki/2015_TG387 https://en.wikipedia.org/wiki/2015_TG387. That's still only .03 ly, but we already know about objects whose orbits go much further.

phkahler 8y ago

>> The object from the article is about 0.0019ly away, so there could be quite a lot of new most-distant solar system objects still to be discovered! And yet, Voyager 1 and 2 have now "left the solar system" and entered interstellar space. It looks to me like the definition of what's part of the solar system is a bit squishy.