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Photograph of extra-solar planetary system! Answered

An article in Science News today shows an infrared image of HR 8799 with three roughly Jupiter-sized planets around it! The speckling in the center (around the "+") is the star.

The same article shows two Hubble images of Fomalhaut taken 18 months apart. The two images show directly the orbital motion of a previously detected planet, Fomalhaut b.

Update (10:12 pm PST 13 Nov 2008): I've attached the two pictures from the SN article. The first is the IR composite of the three-planet system HR 8799; the second is Fomalhaut, showting the offset of Fomalhaut b between 2004 and 2006. I encourage you to read the actual article to get the details of how the data was obtained, and to judge for yourselves its veracity.

Update (12:05 pm PST 14 Nov 2008): The two articles are out in today's ''Science'' along with a news article and editorial (requires subscription).

HR 8799: Morois, et al.
Fomalhaut: Kalas, et al.


Is the universe shrinking, or is it just me?

It's just you: the rest of us are expanding --- or our pants sizes are....

Are you getting a bit excited?

No, just older and fatter...happens in your forties....

Wait.... that's not funny. I'll be forty one day. Doh!

There's a new preprint claiming observation of a Jovian-mass planet orbiting at 8 AU around beta Pictoris. The image was acquired using image-subtraction techniques, and it isn't yet clear whether the object is a true planet, a coincidental alignment, or an instrumental artifact.

Recently I have been IN LOVE with astronomy. I think I'm going to make a group.

Thanks for following up, and discovering the existing groups! If people aren't participating in them, make some noise: announce there existence with a forum topic under Science; see who are already members and PM them to see why they aren't contributing; and so on. That's what I did with Plasmana's Physics Group.

Your last reference to Science Daily is broken. Your text says "!http://www.sciencedaily.com", but you set the hyperlink URL to "!http://smouch.net/lol". If you did this on purpose, too bad :-) I always check the URL via mouse-over before clicking.

The site is great for general science article! I tend to focus on physics, for obvious reasons :-)

I promise to personally track down and throttle the next man to post a rickroll link. Seriously. Don't think I won't.

Hey, that's kind of sexist of you, now isn't it? What if the next f-ing rickroll link is posted by a female? Are you not going to throttle her? Geez...every day, I feel more and more persecuted as the Old White Guy :-(

Don't go all postal on me. It's just a figure of speech. Yeesh. Of course I'd throttle a female RRer.

Mmmm....Postal....Nah, I think the bullets would get there three days late and all folded in half ;-/

Tell me about it. they mangled my sculpey hand terribly...

. It's different when wimmen do it. Any married man should know that.

Hmm. When I hove the links, they never show the sites. I bet you clicked it. :)

Depends on your browser. Safari doesn't show that information. FireFox, which I use, shows the URL down in the very bottom of the window, below the horizontal scrollbar. I'm not familiar with IE.

Another smouch bites the dust.

Well, too bad it is millions of light years away.. :(

Umm, no. Fomalhaut is only 25 light years away, and HR 8799 is still within the Milky Way, probably no more than a couple hundred ly. Farther than that, and the angular size is too small to image this way.

well, if a space craft was traveling 1/4 the speed of light, it would take 100 years to reach the planet

In whose frame of reference? Homework problem...work out how long the trip would be for the people in that space craft, assuming only special relativity (don't worry about gravity, or about stopping or starting). Post the answer here.

ok, i'm not that GREAT at math, but 4 (times) 25 = 100
you are going at 1/4th the speed of light...
(not inside the space craft)

so, ya

so, presuming time stops at the speed of light, they would feel that 25years has passed, if my math is right, of course

No, that's the point of relativity -- the people in the ship feel that time passes at a different rate than for outside observers, in particular tShip = tEarth×sqrt(1-ß2), where ß = v/c.

In this case, you have ß = 1/4, so tship = 100 × sqrt(15/16) = 24.2 years. Not a great difference, but you can see that it's not 25.

Suppose you had the ship travelling at 1/2 the speed of light (not unreasonable for a solar sail). Then tEarth = 50 years, but tShip = 50 × sqrt(3/4) = 43.3 years. That's almost seven years "shorter," as seen by the people taking the trip.

Minor correction to my second paragraph (argh). Change 24.2 to 96.8 (I multiplied by 25, not by 100). The sqrt(15/6) is correct. The whole thing should read:

... = 96.8 years. Not a great difference, but you can see that it's not 100 years.

well, being a sophomore, taking chemistry, and algebra 2, i don't know the Speed of light constant and other stuff, so i can't really calculate what i don't know

. According to Google, "the speed of light = 299 792 458 m / s"
. Wikipedia agrees and also gives it as "≈ 6.71×108 miles per hour" (671,000,000 mph) and ≈ 186 000 miles per second (that's the one that sticks in my head).
. None of those figures really mean much to me - anything over about 200 mph is just really-freaking-fast in my head. ;)

"the speed of light = 299 792 458 m / s" On a side note, that number is ''defined'' as the speed of light. The meter is now defined as 1/299792458 of the distance light travels in one second in vacuum, so if someone comes up with a more accurate measurement of c what will really happen is that the meter's length will change :-) (presumably by less than 3 billionths).

3.0 x 10? meters per second is what my teacher told me, bu ti can't remember the exponent

i assumed that if you went 1/4 the speed of light, time would go by 4 times faster Solar sail, can you explain this concept?

Too many formulas with too many symbols that i do not comprehend

. Using 1/(1 – (v/c)2)1/2, I come up with a time-dilation factor of a little over 3%. So it would take a little over 96 years, subjective time, to travel 100 ly @ 0.25c.
. You have to get to over 0.4c to get 10% and 0.6c gives 25%. You have to get over 0.85c to experience time at half-speed. Ie, one has to be hauling butt to get much dilation.

Your answer was right the first time, you just wrote the description wrong :-). It would take 96.8 subjective (ship-board) years to travel 25 ly @ 0.25c. Alex was computing 100 years, Earthbound, for the same 25 ly trip.

. I feel pretty good about picking the proper equation. Not too shabby for S AR oilfield trash. ;)

I've added links to the original journal articles, published today (online) in ''Science''.

Stop! Lest ye arouse Cthugha from his ancient sleep!


9 years ago