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NASA Discovers 7th Closest Star
Thorfinn.au says "Scientists using data from NASA's Wide-field Infrared Survey Explorer (WISE) have discovered the coldest class of star-like bodies, with temperatures as cool as the human body. Astronomers hunted these dark orbs, termed Y dwarfs, for more than a decade without success. When viewed with a visible-light telescope, they are nearly impossible to see. WISE's infrared vision allowed the telescope to finally spot the faint glow of six Y dwarfs relatively close to our sun, within a distance of about 40 light-years. 'WISE scanned the entire sky for these and other objects, and was able to spot their feeble light with its highly sensitive infrared vision,' said Jon Morse, Astrophysics Division director at NASA Headquarters in Washington. 'They are 5,000 times brighter at the longer infrared wavelengths WISE observed from space than those observable from the ground.'"
40 lightyears! I hereby dub these "ninja stars", for their ability to sneak up on us like this.
http://alternatives.rzero.com/
They are (relatively) cold. They are also (relatively) close.
http://alternatives.rzero.com/
I'm not sure that NASA is taking the most efficient path here: If you want to discover cold, distant objects, any marriage counselor who is a bit flexible about confidentiality should be able to provide you with dozens of them, without any of the trouble of sophisticated infrared astronomy...
Bring back PizzaAnalogyGuy! He had real promise as an up-and-coming troll, but sadly fizzled out too quickly.
Nope, no typo.
FTFA:
The Y dwarfs are in our sun's neighborhood, from approximately nine to 40 light-years away. The Y dwarf approximately nine light-years away, WISE 1541-2250, may become the seventh closest star system, bumping Ross 154 back to eighth. By comparison, the star closest to our solar system, Proxima Centauri, is about four light-years away.
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If what I just said sounded like a troll, it was probably just a failed attempt at humor.
Based on how many cold dwarf stars we have found so far, there may be stars like this one within 2 LY or less. In which case they would make for a great candidate for a high speed interstellar probe.
Tsukasa: All I really want, is to be left alone...
Closer than you're comfortable with, and colder than you can possibly imagine.
Closest, yes. Coldest? Maybe - but what if they're inside Dyson spheres and just not radiating much to the outside universe?
Isn't it cool that we're working on launching an infrared telescope into space, which might discover that there are lots of such things all over the place? Oh wait, congress is suddenly saying that we can't afford it, even though it costs less than the air conditioning budget for 60 days of the Iraq occupation. (link)
Then that would be the most awesome finding ever.
The Kruger Dunning explains most post on
Yeah well, that's coming from a guy who never made the Kessel Run in under 12 parsecs!
The world's burning. Moped Jesus spotted on I50. Details at 11.
No, it does not. Allowances were made for brown dwarfs, and they do not in any substantial way bump up the amount of observed mass.
The world's burning. Moped Jesus spotted on I50. Details at 11.
Do you want to be the one to tell a bunch of soldiers that they have to go without air-conditioning for two months?
http://alternatives.rzero.com/
At what point do we start to see a picture of the small/cold tail of size distributions? One of the questions that interests me greatly is the frequency of rogue planets in the interstellar medium. If you could see a curve of brown dwarf sizes (weighted by the difficulty of detecting them), it would be fun to just naively extend the graph and see how common gas-giant sized objects would be relative to detectable stars.
He posits a large number of these dwarf gas giants, and a spacefaring civilization that lives around them: http://www.kschroeder.com/my-books/permanence
PHEM - party like it's 1997-2003!
I think one of the definitions of a brown dwarf is that there is no sustained fusion (I think the larger ones can have limited fusion reactions, but many orders of a magnitude less than even a dim, cool star).
The world's burning. Moped Jesus spotted on I50. Details at 11.
I'll share with you a technique that has helped me immeasurably throughout my life: when I find a glaring mistake in someone's output, something that they just should not have overlooked, I first assume that I've misunderstood something and the mistake is actually mine and check again. 90% of the time, it saves me from looking like a jackass.
I think it's a fuzzy definition, and I don't think there's ever been any consensus on calling them stars. Pretty much every article I've read on them refers to them as brown dwarfs (or M, L, Y or T dwarfs), so I'd fault the editor of that one for sloppy use of the word. I don't think you can call any object that doesn't have sustained fission reactions a star, and certainly not one radiating at around the same temperature as a human body.
The world's burning. Moped Jesus spotted on I50. Details at 11.
Sure we could build something faster, but fast enough? We need something 2-3 orders of magnitude faster to be really useful. That's a tall order.
No, not really. Helios was a fat-a** at about 820 pounds. A ham radio microsat sized probe plus an actual intention to "go fast" could probably go 3 orders of mag faster. You can get two orders of mag just by thinning the probe weight, maybe another if you go gonzo on booster and upper stage size and really fine tune the gravitational assists.
I've often wondered if you combined the X-15 goal of "just go fast, that's all" with a space probe, just what would happen, exactly... Probably something the size of a saturn-5, launching a truly giant ion upper stage, launching a tiny little probe the size of AO-51 (two dozen pounds, more or less)...
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
Hmm, let's do a quick check of the numbers.
According to Wikipedia, we can reasonably expect 5000 seconds Isp from a VASIMR, but let's assume ten times that, just for grins.
So, one year (365.24 days) at 0.98 m/s^2 acceleration implies deltaV of 30925 km/s.
30925 km/s @ 50000 seconds Isp translates to a mass ratio of 2566254356903250866674835623:1.
So, a 10 kg probe (including drive and fuel tankage) would require 25662543569032508666748356229 kg of reaction mass. Which is about the mass of the Sun...
So, no, this would NOT be even semi-reasonable....
"I do not agree with what you say, but I will defend to the death your right to say it"