Extrasolar Planet Discussion - Now Discussing: KEPLER announces hundreds of candidates

The Hubble Telescope discovered another moon orbiting around Pluto, currently named "P4" until a permanent name is given to it. Hubble itself also "discovered" Pluto's moon's Nix and Hydra back in 2005, and may have also imaged P4 back then, but it may have been overlooked because there wasn't enough illumination to view it properly.

P4 has an estimated diameter of 8-21 miles and is the smallest of Pluto's known moons. The fact that Hubble detected it is somewhat remarkable, considering that it sits 3 billion miles away from Earth. A photo of P4 was first taken with Hubble's Wide Field Camera back on June 28, and then confirmed through a series of other images leading to now.

Pluto is currently being focused on as a lead in to NASA's "New Horizon's" mission, which is slated to fly past Pluto in 2015 and skirt around the outskirts of the solar system. (The New Horizon's probe is approximately half-way to Pluto right now)

 

There is a good chance that one of the planets already discovered have life on them; probably only very primitive, like bacteria; but that would be incredible. The sad thing is that there is no way to know if there is life on any of the planets; even if we discovered a planet in the habitable zone we could only guess that life would exist. So the planet hunt is really exiting, but also a little frustrating, since there is no way we can confirm life forms on them. Imagine discovering the perfect planet; close to earth-like, but not being able to act on it or do anything about it.

How long will it be till we have the technology to travel between stars? 4,2 lightyears is not to far if we could make it close to lightspeed; thats the distance to our closest neighbouring star. Doesnt look very promising though. I wonder how far Voyager 1 have gotten by now; has it left the solar system? Is anyone updated on this information? What an exiting journey it must be for that little droid; despite all the empty blackness everywhere of course.

But you know what; at one point in our history the vast blue sea was almost an overwhelming barrier to overcome for mankind; now we face the vast black sea of space. Will we ever be able to cross it, or will we be stuck on this island for as long as we exist. I wish i had been born in the year 300 000; maybe by then we would be able to leave the solar system somehow.

I always digress discussing these things..

 

While we can't tell that a planet is lifeless, we CAN tell if a planet has some forms of life. Oxygen as an individual gas, while produced by life, wouldn't occur through chemical/geological processes, just biological ones. Of course, it's entirely possible that one could have life that doesn't produce oxygen that wouldn't be detected, but it does mean that a large amount of oxygen in the atmosphere of a planet would be a very strong indicator of life that we can look for from here.

And Voyager 1 is 118 AU away from the Sun right now. Which is only something like 0.002 light-years, and is arguably somewhere around where the edge of the solar system is, give or take.

 

Oh, no.
That means the secret's out.
[image=http://upload.wikimedia.org/wikipedia/commons/5/56/The_Sounds_of_Earth_Record_Cover_-_GPN-2000-001978.jpg]
We're doomed!

 

Yes, thats true. Certainly oxygen detected in the atmosphere would be a strong indicator of life, no doubt. But still.. i really want to see a picture of an alien The sad thing is that the interest for space travel and discovery is limited around the globe, and we are all caught up with all the troubles of this world; so if a bacteria or anything is ever discovered on another world it wont make the front page i think. Just like i dont believe alot of people are even aware that we actually have discovered many planets outside our own solar system. I believe these things are important. I dont know if i remember correctly, but didnt Obama cut the spendings on research, space technology etc.. Sad, but understandable of course.

Funny to think that the Voyager satellite will float in space for houndreds of thosands of years unless it hits something one day.. It will be a relique left behind by a species called homo sapiens sapiens; imagine if someone discoveres it in some distant future; they will write stories about us..

What is actually interesting is that the first radio signals ever broadcasted must have travleled quite a distance by now; just waiting to be picked up by an alien radio station.

 

OK, this one is for Lowie, or anyone who has the knowledge, really...

Einstein's Special Relativity theory says that nothing can travel within space faster than the speed of light. That speed is an accepted value. However, another on-going theory, supported by observation, states that space itself is expanding faster than the speed of light. I think I understand the concept, in that space can bend, fold, and distort itself due to things like gravity and other forces, so that it might not actually move faster than light, only take "shortcuts" that make it appear so. But then, how are galaxies continuing to move farther, and faster away from each other?

I'm thinking of the "lonely galaxy" theory put forth by Lawrence Krauss and others which says that over time, the galaxies will no longer be able to perceive each other, because 1)the distances will be too great between them, and 2)as expansion speeds up, the galaxies will move faster than light, which means that light will never reach the others. In other words, what we are viewing now is light from millions of years ago, when the galaxies were closer, and before they started accelerating faster than light. At some point, everything outside our galaxy "horizon" will just go dark. It's a rather complex idea, which is certainly beyond my current limited knowledge.

 

As a bonus to the above question, it looks like the Kepler observatory just discovered 11 new star systems containing 26 new planets outside of our solar system. It seems like 15 of those planets fall within the "between Earth size and Neptune size" zone, which might yield compatible Earth like life.

So far, Kepler has found 61 confirmed planets, and 2,300+ possible candidates.

 

I'm not ure what you mean about a theory concerning space moving faster than light. You can get an increase in distance between to objects that is faster than light, a galaxy going one way at 100,000 miles a second while another goes in the opposite direction a the same speed so that the combined velocity shows them increasing their disance at 200,000 mps but still nothing with mass is moving faster than light in this example.

Space can expand as fast as it wants, but everything in space is still moving stl.

 

I suppose this is more in line with what you outlined in your first paragraph, but it's not a case that 2 galaxies are moving away from each other at a fixed rate, like cars travelling in opposite directions on the interstate at 55MPH, which is what your example seems to cover. It's more like compound interest, in that they may moving away from each other at 100,000 miles a second right now. In a million years, that speed will have increased to 110,000 mps. In another million years, the speed will be 190,00 mps.. and so on. The theoretical acceleration of space has no limits, and if the universe is roughly 14 billion years old, you can see the tremendous velocities that may be involved. (I certainly don't know what they are, besides trying to imagine a LARGE number)

If space is a balloon with 2 points drawn on the skin of the balloon, what happens when the balloon itself is inflated with 1)an infinite supply of helium, and 2)a valve that can generate ever increasing psi? The 2 points move away from each other, but they aren't really moving, because the entire balloon itself is expanding. But what governs the rate of the celestial helium flow into the balloon? The topic was explored in a segment within BBC's miniseries Hyperspace. (It's kind of like Cosmos, but hosted by Sam Neill) and it's a theory of Lawrence Krauss outlined in his many books. The "lonely galaxy" theory says really that any beings in our galaxy who want to visit other galaxies had to do have developed the capability by now, barring some as yet unknown force. Because, at some point, our galaxy will move beyond the perception of every galaxy around it. If we ever achieve extra-system travel, we'll most certainly be limited to the planets within our ow galaxy. I suppose this is good enough simply due to the sheet number of planets in our galaxy, but it's kind of a bummer from the standpoint of imagination.

So yeah, I guess my original question goes back to your final sentence. What do you mean by "space can expand as fast as it wants" then? What aspect of physics governs the movement? I still don't think it's a matter of space moving as fast as it wants, because even as the acceleration is increasing, there has to be some sort of valve, or stopwatch or something....

 

Well, the expansion of the universe at present is associated with the Hubble constant, which you get from plotting a bunch of galaxies based off velocity and distance and then finding the slope of that line. The Hubble Constant is about 70 (km/s)/Mpc. Which means that if you had two galaxies 1 Mpc away, in 1 second, they'll be 70 km further apart. If it's 2 Mpc away, then in 1 second they'll be 140 km apart. The most distant galaxy we know of is 13.2 billion light years away. That's about 4 million Mpcs. Which means that galaxy is moving away from us now at a current speed of about 280 million km/s, if my quick math all checks out. The light we're currently getting from it is old light, though.

 

So yeah, I guess my original question goes back to your final sentence. What do you mean by "space can expand as fast as it wants" then? What aspect of physics governs the movement? I still don't think it's a matter of space moving as fast as it wants, because even as the acceleration is increasing, there has to be some sort of valve, or stopwatch or something....

A better answer could be given if we had a ToE. I don't know where the valve is or what is filling it. Dark matter, dark energy, these are unknowns.

Space moving, space expanding, it starts to get very semantic. You could pull back and just say distance is increasing and distance, or space, or whatever is not a thing. Locally, and by locally I mean no matter where you are it is "local", nothing is moving ftl and nothing can.

No one has the answer as to wether we are going to keep expanding, or that the expansion will keep accelerating, or that The Big Rip will occur, or that things will just get ou of site from each other in all directions. It might be a lil frustrating but "I don't know" is the actual answer across the scienfic community.