Brown Dwarf With Water Clouds Tentatively Detected Just 7 Light-Years From Earth

sciencehabit (1205606) writes Astronomers have found signs of water ice clouds on an object just 7.3 light-years from Earth — less than twice the distance of Alpha Centauri. If confirmed, the discovery is the first sighting of water clouds beyond our solar system. The clouds shroud a Jupiter-sized object known as a brown dwarf and should yield insight into the nature of cool giant planets orbiting other suns.

Comments

Is this the missing "dark matter"?

[Anonymous Coward]

There was not enough mass in what we can see from the galaxies. And people came up with strange theories like dark matter.

Now we have an (arguably not so super heavy, but nonetheless) object just around the corner. Could it be that there's no dark matter, but that simply the galaxies are full of these things?

Re:Is this the missing "dark matter"?

[Buggz]

Logic fail. Dark matter can be explained by such small objects if they are incredibly numerous. It's just math: divide the missing mass by the mass of one brown dwarf to get the number needed. If you want to disprove the brown dwarf explanation you need to explain why the number that is needed contradicts something.

The hypothesized dark matter does not emit or absord any type of electromagnetic radiation, in other words it does not interfere with or react to light. Numerous small objects would. Also, and this is the most important bit in your logic fail fail, if you have enough small objects to account for five times the mass of the visible universe, you would have something five times more visible than the visible universe. Matter attracts other matter (which is why there is a dark matter hypothesis to begin with, something invisible attracts the visible) and such a copious amount of "small objects" would form larger objects. Which is how stars and planets form to begin with.

Re:Is this the missing "dark matter"?

[Anonymous Coward]

No, they have not eliminated the possibility that dark matter does interact with electromagnetism weakly, which is the basis of some particle detection searches and some scans of the skies for things similar to antimatter-matter interactions. But they have pretty much eliminated that dark matter is dense piles of regular matter (e.g. brown dwarfs, or black holes, or rogue planets) by doing microlensing surveys which set an upper bound on the number of such objects. If there were enough to account for dark matter amounts required for rotation curve of galaxies, they would have seen way more microlensing events than they did. This applies regardless of evidence suggesting that dark matter is not baryonic (the same evidence points out that there is unseen regular matter too, which would mean there is stuff like this not yet observed that needs to be found before you would even start edging into the dark matter category).

Occam's razor.

[TapeCutter]

Could it be that there's no dark matter, but that simply the galaxies are full of these things?

Could it be that all the cosmologists and physicist who have been looking at this for a couple of decades somehow missed that blindly obvious "possibility". Or is it more likely you are simply unaware of the evidence that forces these people to dismiss the obvious "common sense" answer?

Re:Occam's razor.

[TapeCutter]

How was my reply "uncivil"? Blunt with just a hint of sarcasm certainly, but there's nothing in there that should offend someone who is genuinely interested in an answer. In fact I deliberately used the word "unaware" because "ignorant" is normally viewed as derogatory (even though it actually isn't).

If you feel a gentler more informative answer can be provided then why not provide it? I'm sure the OP is quite capable of defending himself against my prose if it has unintentionally offended him in some way that I'm unaware of. What I'm not so sure of is why do you feel the need to be offended on his behalf?