Finding planets difficult? Doubt it!

[christovas]

<br />I find it ridiculous that it has been so difficult for scientists to locate planets beside their Stars. Consider this; I've recentely read that the twin telescopes created for finding planets will use a method of "cancelling" light from the star by way of "aligning" crest to trough of photons, etc... (A little paraphrasing added there)<br /><br />My thoughts are that this is truly absurd that it can be THAT difficult to find a few planets without the wobble method. You're telling me with today's technology you couldn't take a detailed image of a nearby star with an infrared telescope of some type and map that data out. You're telling me that there wouldn't be obvious "distortions" in the imagine albeit miniscule?! <br />How do we determine the composition of local planets? We take various measurements of light reflected off of the surface of the planets.<br />Stars are typically comprised of a couple of elements, no?<br />If there is a deviation in the image(composition), would that not imply a planet? This kind of eleminates the whole "star in the backgroud" issue too, no?<br />But how can we test this? Why not just use a lower-end telescope of some type and try to look at our sun when one of our planet moves nearly behind it. <br />I figure the big boys with big telescope should be able to do this with ease. Take the image, get the composition image, "oh look, this little spot here is different from the rest of the GIANT BLOTCH." <br /><br />Am I way off here guys? <br /> <br />

 

[nacnud]

<font color="yellow">Am I way off here guys? <font color="white"><br /><br />Yes,<br /><br /><font color="yellow">Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the drug store, but that's just peanuts to space.<font color="white"><br />Douglas Adams<br /><br />Even with all the clever optical tricks it's going to take something like ESA's Darwin to directly observe an extra solar Earth like planet.</font></font></font></font>

 

[robnissen]

There are at least two huge problems with your method. First, your method (such as it is) would only work for the very small minority of cases where earth, the extrasolar planet and its star are all in the same plane. Second, we have seen the surface of exactly two stars: the sun and Betelgeuse (sp?). The rest of the stars are just point light sources. To try to see differences on the order of a millionth or a billionth of a percent in the fluctuation of that pixel light source is beyond our current capabilities.

 

[christovas]

Thanks, nice explanation. As far as the conspiracy thing, I'm not that type and that's not what I was implying. <br />While your explanation covers a bit of what I was saying, it still didn't do it for me. Maybe u can go into a little more detail. Here's where I have problems in your argument. <br />-Yes, planets reflect light, much like ours do and that is how we find the composition of their atmospheres. I'm only -guessing- if they did the same for a star, there would be some consistancies(star matter) and hopefully, small bits of inconsistancies (planets if they exist). <br /><br />You use the argument of seperation, but I don't think that is a strong enough argument. If the planet is fairly close (0-3 AU) and is of a decent size, the reflected light should be in there somewhere. <br /><br />Now this is going off of my assumption that looking at a star image (composition-wise), isn't like looking at a bunch of "garble" and it is somewhat orderly. I'm going to research a little more about Fraunhofer lines. <br /><br />Thanks for the reply. If you can expand further on your arguments, please do. I would really like to know why they can't do what i propose. <br /> <br /><br />Oops I missed your response RobNissen. Thanks for elaborating. <br />So what you are telling me is just pure and simple; it's out of our reach techonoloy-wise to see enough data from a nearby star to do what it is I'm guessing they should be doing?<br />So what you are

 

[alokmohan]

Every alternate day they keep on discovering planets.How funny to to see to many genius.

 

[absolutezero]

Here is the explanation about Darwin that can explain what your looking for.<br /><br />"Looking for planets around even nearby stars is like trying to discern, from a vantage point 1000 km away, the feeble light from a candle next to a lighthouse. At optical wavelengths, a star outshines an Earth-like planet by a billion to one. Partly to alleviate this difficulty, Darwin will observe in the mid-infrared. At these wavelengths, the star-planet contrast drops to a million to one, making detection somewhat more manageable."<br /><br />As you can see though, infrared is the way to go when looking for Earth like planets. On Earth, biological activity produces gases that mingle with our atmosphere. For example, plants give out oxygen and animals expel carbon dioxide and methane.<br /><br />These gases, and others, such as water, leave their fingerprints by absorbing certain wavelengths of infrared light.

 

[christovas]

EXACTLY!!! <br />Absolutezero, that's what i've been trying to preach. People keep giving me these bug-next-to-bonfire analogies when i'm wasn't talking about the visible spectrum. I'm talking about photons, infrared, phases, shifts, and variables, and all the jargon that help scientist figure out the composition of a distant object.

 

[mrmorris]

<font color="yellow">"If the planet is fairly close (0-3 AU) and is of a decent size, the reflected light should be in there somewhere. "</font><br /><br />Everyone seems to have focused on the relative light levels as the reason it's difficult to discern planets around stars. The other reason of course is that the planets are so close to their sun when seen from this distance. Let's work out what kind of separation we see for a star with a planet at 3 AU at a distance of 10 light years from earth.<br /><br />1 Astronomical unit (A.U.) = 149,598,073 kilometers<br />1 light-year = 9,454,254,955,488 kilometers<br /><br />So the planet is ~448,794,219 km from its star, and ~94,542,549,554,880 kilometers from Earth. Working this into more visual terms (and trying to keep the ratios reasonably constant), we'll assume the sun is the size of a grapefruit. The planet is about the size of a apple seed and sits about two meters away from the grapefruit. We're 420 kilometers away from the grapefruit/apple seed system and are trying to locate the seed.

 

[absolutezero]

If an astronomer is looking at a star through infrared, while its a different spectrum of light, do they still experience the same problem as if they were looking for a planet around the star with visable light on how it is still almost impossible to see because of the shear size of the planet to the star or does that not apply since we are looking through infrared rather then visable light?

 

[mrmorris]

<font color="yellow">"If an astronomer..."</font><br /><br />1. You win the award of the day for the most incredibly run-on and rambling sentence.<br /><br />2. Infrared or visible light -- stars are really really far away and planets are relatively really really close to their home sums. Separating the two is incredibly difficult. The reason why Spitzer was able to take pictures of two planets via infrared wavelengths when the same is not possible via visible light is because the planets were *very* close to their home sun and the difference in the amount of radiation emitted in the infrared wasn't <b>quite</b> as enormous as in visible light. Instead of a firefly next to a 10 million candlepower lighthouse beacon, it was an LED next to a 1 million candlepower spotlight. <br /><br />This is in part because the only visible light that comes from planets is what reflects from their home star. That light is incredibly small compared to the light put out by the sun, as only the <b>tiniest</b> perdentage of the sun's light actually hits the planet, and since planets aren't 100% reflective -- only a small fraction of <b>that</b> light actually gets reflected for our viewing pleasure.<br /><br />By contrast -- the two imaged planets were 'Hot Jupiters' and they not only were very close to their home star (increasing the fraction of radiation they received from the star), but also produced their own heat internally, both from normal planet formative processes and because they are constantly being gravitationally heated in their close orbit around the star. Therefore, they were able to be imaged in the IR. However, they are both special cases. We could not, for example, get an IR image of an Earthlike planet at 1 A.U. around those same stars given current technology.