Well of Souls Forums

hi hi

This one is sorta old news, but it seems like NASA is planning on capturing a small asteroid and pulling it into Earth orbit. Which I think is really cool.

Even if we'll probably never build a space elevator, and we won't need it for an anchor, there's still a vast amount of mineral wealth in them asteroids.

(Also, this gives me an excellent opportunity to link this video from Kerbal Space Program. The Kerbal Space Slam!)

NASA's Spitzer and WISE Telescopes Find Close, Cold Neighbor of Sun
Source

Yeah, that's two brown dwarf systems within 7 light years. If brown dwarf systems are as common as red dwarfs (as seems likely), or perhaps even more common, then that's an awful lot of mass that's been completely unaccounted for.

I'm starting to wonder how many rogue planets they'll start discovering in Sol's neighbourhood say in a decade or so.

GeoModder wrote:I'm starting to wonder how many rogue planets they'll start discovering in Sol's neighbourhood say in a decade or so.

Actually that's an important element of the recent WISE surveys: the fact that they're able to detect cool brown dwarfs 7 light years away is making it less and less likely that there are still undiscovered large planets poking around the edges of our own system.

Arioch wrote:Yeah, that's two brown dwarf systems within 7 light years. If brown dwarf systems are as common as red dwarfs (as seems likely), or perhaps even more common, then that's an awful lot of mass that's been completely unaccounted for.

Isn't that what Dark Matter was theorized for? IIRC Relativity wasn't working quite right because things were behaving as if there was a lot more mass than we could see, hence Dark Matter was theorized to fill the gap. An abundance of brown dwarfs could solve that.

fredgiblet wrote:

Arioch wrote:Yeah, that's two brown dwarf systems within 7 light years. If brown dwarf systems are as common as red dwarfs (as seems likely), or perhaps even more common, then that's an awful lot of mass that's been completely unaccounted for.

Isn't that what Dark Matter was theorized for? IIRC Relativity wasn't working quite right because things were behaving as if there was a lot more mass than we could see, hence Dark Matter was theorized to fill the gap. An abundance of brown dwarfs could solve that.

Yes, that's what I was referring to. I have the feeling that astronomers have grossly underestimated the mass of unseen systems (like brown dwarfs), interstellar gas and dust, and black holes.

Arioch wrote:

GeoModder wrote:I'm starting to wonder how many rogue planets they'll start discovering in Sol's neighbourhood say in a decade or so.

Actually that's an important element of the recent WISE surveys: the fact that they're able to detect cool brown dwarfs 7 light years away is making it less and less likely that there are still undiscovered large planets poking around the edges of our own system.

Oh, I meant with "Sol's neighbourhood" lightyears outthere, not in say the Kuiper -or Oortbelt of our system.
Personally, I don't think the changes of detecting a jovian-mass planet on Sol's outskirts are high. Not with the current record of detecting dwarf planet candidates in the same areas.

I've got a vague memory of recently reading (on ArsTechnica, I think) an article that mentions near-consensus among at least one group of scientists that there's probably something Earth sized or bigger beyond main Kuiper belt but probably not as far as Oort cloud distance. Something about a recent finding making this more likely.

fredgiblet wrote:Isn't that what Dark Matter was theorized for? IIRC Relativity wasn't working quite right because things were behaving as if there was a lot more mass than we could see, hence Dark Matter was theorized to fill the gap. An abundance of brown dwarfs could solve that.

Oh I hope so. It would take an awful lot of stuff out there, like implausibly high values of "lots", but oh the schadenfreude. From memory dark matter is supposed to be like 80% of the mass of the universe. Think I said before how dark matter flags my phlogiston filter.

Nemo wrote:

fredgiblet wrote:Isn't that what Dark Matter was theorized for? IIRC Relativity wasn't working quite right because things were behaving as if there was a lot more mass than we could see, hence Dark Matter was theorized to fill the gap. An abundance of brown dwarfs could solve that.

Oh I hope so. It would take an awful lot of stuff out there, like implausibly high values of "lots", but oh the schadenfreude. From memory dark matter is supposed to be like 80% of the mass of the universe. Think I said before how dark matter flags my phlogiston filter.

Dark matter represents about 27% of the mass-energy of the universe. It's about 85% of the total amount of matter, though. This is based on the current standard model of cosmology, which is currently the best fitting description we have of the universe.

As to your, and everyone else's, "phlogiston filter" it's interesting how often it gets brought up in this context (along with the aether). Unlike phlogiston, however, dark matter actually has a very strong theoretical underpinning. There are indirect observations of its existence (galactic rotation curves, galactic clusters, large-scale universe structure, artifacts in the CMB, gravitational lensing). Add to the fact that cosmic models that include dark matter are the only ones that get close to producing what we observe the universe to actually be.

Dark matter isn't random. It was proposed to explain observations of stellar motion in the 1930s. Observations since then have only added to its theoretical existence. And, based on our current understanding, it allows us to explain the universe from the Big Bang to now. To date, no modified theory of gravity has been able to produce the same results to the same level of accuracy.

There's a little bit of Occam's Razor involved with dark matter. It's the simplest explanation for what we see. That's not to say it's ultimately right, but that does give it a leg up on the much more complicated modified theories.

I highly recommend the Wikipedia article on Dark Matter. It's actually a very well written synopsis of the current state of the theory and is well-sourced. It includes a discussion and links to alternative theories.

I understand the theory and underpinnings, and the alternative theories don't pan out.

And, based on our current understanding, it allows us to explain the universe from the Big Bang to now.

This is the part that hangs in the phlogiston filter. Our understanding of things is so complete that when observations don't quite match up there is something wrong with the observation. Yes our understanding of things works well enough for what we do with it and yes non-baryonic matter keeps the current models functioning. Its useful as far as that goes, but in the back of my mind it tingles. There is no (or very little) math to justify that tingle, that doubt. I simply want it to be wrong because I don't want theory to trump contradicting observations.

I believe this is the closest to a pure technology thread, so I'll just leave this here: http://www.theguardian.com/science/2014 ... -positrons

Next stop, replicators?

Grayhome wrote:I believe this is the closest to a pure technology thread, so I'll just leave this here: http://www.theguardian.com/science/2014 ... -positrons

Next stop, replicators?

It said in the article that they aren't on the verge of creating everyday objects.

Scientists can teleport atoms. Doesn't mean they can teleport a person. All this experiment proves is that E=MC^2. That's important, sure, but I'm not sure it has a physical use. Except maybe for providing reaction mass to interstellar spacecraft.

Astronomers Find a New Type of Planet: The "Mega-Earth" Link

Suederwind wrote:Astronomers Find a New Type of Planet: The "Mega-Earth" Link

It's a bit goofy that they insist on classifying every rocky exoplanet as some flavor of "Earth." Kepler-10c is as massive as Neptune and has a smaller orbit than Mercury; it's nothing at all like Earth.

It's a bit goofy that they insist on classifying every rocky exoplanet as some flavor of "Earth."

Yes, Stracciatella would be much better.

Jokes aside: a planet as massive and as close to the sun as this one would come very close to anyones idea of "hell".

Good news!

The Churymov-Gerasimenko comet has entered Rosetta's sights, and more interestingly, it appears to be a contact binary!

Found an interesting article about caves on the moon: Link
I didn't even know such things exist up there. Anyway, Nasa thinks (Link) that they could provide shelter for future settlements.

Fantastic News!

As you know I've been following the progress of Rosetta, from my periodic posts of it's achievements on these forums.

It's been over 10 years in the waiting, but finally Rosetta has just recently entered into orbit around comet 67P (Churyumov-Gerasimenko), a first in space exploration history. Delivering stunning detail of the comet. The Philae lander carried by Rosetta will hopefully be able to land on the surface for November 11th.



EDIT: Link fixed