[ Sandy/NASAChatHost - 1 - 09:44:23 ]
Welcome to today's chat with Astronomer Sten Odenwald! Sten will begin answering questions at 11 am, Pacific (2 pm Eastern). Look forward to chatting with you then!

[ Sandy/NASAChatHost - 3 - 11:06:28 ]
RE: [Stephanie/Edmonton] Hi Sandy!
Hello Stephanie! Long time no hear from you! I've seen your name in other Quest chats, so I know you've been around! I'm really happy you could make it to Sten's chat today! I know you will have some great questions for him :-)

[ odenwald - 4 - 11:09:27 ]
RE: [Sandy/NASAChatHost] Hello Stephanie! Long time no hear from you! I've seen your name in other Quest chats, so I know you've been around! I'm really happy you could make it to Sten's chat today! I know you will have some great questions for him :-)
Hi! I recognize you too!! What's on your mind this week about space?

[ Sandy/NASAChatHost - 7 - 11:12:12 ]
RE: [odenwald] Hi! I recognize you too!! What's on your mind this week about space?
Todays chat with Sten will revolve around questions related to the Earth and the Sun and their interactions. We will begin in just a couple more minutes...

[ Sandy/NASAChatHost - 9 - 11:13:02 ]
RE: [Raquel/SP/Brazil] Hello !
Hi Raquel, welcome to another chat! Glad you could make it :-)

[ Sandy/NASAChatHost - 10 - 11:13:42 ]
Welcome everyone! Sten is ready to answer your questions. Hello Sten!

[ odenwald - 11 - 11:14:20 ]
RE: [Stephanie/Edmonton] Hi Sten, I've been following Stardust processing via webcam.
Stardust is a pretty neat mission, I know a little about it, but havent followed it too closely. You probably know more than I do!!!

[ odenwald - 13 - 11:16:03 ]
RE: [Raquel/SP/Brazil] I have read that the universe expansion rate is around 73 kilometers per second per megaparsec. Will the Solar System be significantly affected by this expansion rate until the sun become a White Dwarf ?
Nope! The current value for the Hubble COnstant..the rate of the current expansion of the local universe, is about 65-70 km/sec per million parsecs. The expansion of the universe only affects collections of matter that are bigger than most clusters of galaxies. Individual galaxies..stars...solar systems do not 'stretch' according to big bang cosmology.

[ odenwald - 16 - 11:19:53 ]
RE: [Stephanie/Edmonton] How would you explain dark matter?
OK..ill try. Dark matter is a hard to see, and possibly invisible, ingredient to the universe which produces gravity just like ordinary matter and energy do. We know that distant clusters of galaxies cannot be stable unless most of the gravitating 'stuff' in them is 'dark matter'. even our milky way is spinning much too fast for only its stellar, visible matter to be the only gravitating stuff. Exactly what this stuff is we dont know, except that it cannot be made from protons, electrons or ordinary matter, because too much is needed. people have considered many forms of matter, but so far all we know is that between 10-100 times more of this is 'out there' than the matter we can see in stars and gas. Its is one of the great current mysteries in modern astronomy.

[ Sandy/NASAChatHost - 17 - 11:19:53 ]
RE: [Renae-Renae/TheBridgeSchool] We have a group of Kindergarten-3rd graders who are on-line for their first chat session. They want to know what a black hole is.
Welcome Renaeo and the Bridge Schol Kindergarten-3rd graders! We are very happy to have you with us today:-) Sten will answer your question in just a few moments!

[ odenwald - 19 - 11:21:52 ]
RE: [Raquel/SP/Brazil] I don't understabd how particles of spin 1/2 ( fermions) have one of its revolution = 720 degrees. Do they have 2 rotational movements at the same time ?
When we speak of a particles 'spin quantum number' you must kep in mind that this quantity really has nothing to do with rotation in the normal sense. There are many quantum numbers that have absolutely NO analogs in the macroscopic world...no matter how cleverly we have named them ( color, spin, strangeness, charm...etc). rotation and 'spin' are not the same things physically.

[ odenwald - 21 - 11:23:30 ]
RE: [Renae-Renae/TheBridgeSchool] We have a group of Kindergarten-3rd graders who are on-line for their first chat session. They want to know what a black hole is.
A black hole is an object that has collapsed so far that its gravity prevents light from escaping. If you take a star like the sun and collapse it to a black hole, it would only be about 3 miles in diameter.

[ odenwald - 22 - 11:26:00 ]
RE: [Stephanie/Edmonton] I've heard that Pluto could be reclassified as asteroid. Was a decision made yet?
Not that I know of...but the International Astronomical Union is deliberating on this issue. Astronomers have long recognized Pluto as an oddball. Now, we know that there are over 75 other bodies beyond the orbit of neptune which have sizes up to 300 kilometers, and with orbits not much different than Plutos. This is why some astronomers think it is time for us to classify Pluto as the largest trans-Neptunian 'Kupier belt' object, rather than a real planet.

[ odenwald - 24 - 11:27:48 ]
RE: [Raquel/SP/Brazil] Do gravitons have mass ?
First, we dont even know if they exist!! Theory says that they will have no rest mass, they will have a quantum spin of 2 units, and will only interact gravitationally. That's about all we know about them...and we have absolutely no idea how to detect them individually!!

[ Sandy/NASAChatHost - 25 - 11:29:59 ]
Renae: Even though a lot of these questions today are at a higher than K-3 level, please don't let that stop you and your kids from asking questions! Sometimes chat are at higher levels and sometimes lower; it all depends who shows up. We want you and your kids to keep sending in their questions :-)

[ odenwald - 27 - 11:31:00 ]
RE: [Raquel/SP/Brazil] But there are lots of books that say that spin1 = 360, spin2= 180 spin 3/2= 540, spin 1/2 = 720,... So, is it incorrect ?
Hmmm...I dont know what they could be refering to. QUantum spin acts, mathematically, like a kind of rotation in space, but it is a quantized rotation. 1/2-integer spin particles can point 'up or down' only, Spin-1 particle can vectorially combine in three ways, +1, 0 and -1. etc. You ned to look at an intro quantum mechanics book on spectroscopy to get the details.

[ odenwald - 30 - 11:32:58 ]
RE: [Stephanie/Edmonton] What is Lambda? What is Omega (and how does it affect whether the universe will expand forever, stop, or crunch)?
Lambda is the symbol used to refer to the magnitude of the cosmological constant...Omega is the ratio of the critical density of the universe derived from the Hubble Constant, and the particular component contributing to the gravity. Omega ( total) = Omega(matter) + Omega(dark matter) Omega(lambda).

[ odenwald - 31 - 11:33:52 ]
RE: [Renae-Renae/TheBridgeSchool] Why does Jupiter have a big hole in it?
There's no hole in it...just a big red spot, which is probably a huge Hurricane. We dont know how it started, but its only ben around about 350 years or so.

[ odenwald - 34 - 11:36:07 ]
RE: [Raquel/SP/Brazil] How can humans detect X-Rays or any high frequency waves from distant galaxies ? Why don't we detect lower frequency waves ( because of the cosmological and gravitational redshift ) ?
because for the distant X-ray sources, even if we se them at a redshift of, say 1.0 or 2.0, this still places the region of their emission in our X-ray band here at earth. We detect optical radiation from distant galaxies even with the redshift, because these galaxies emitted radiation at still shorter wavelengths which now gets shifted into our optical band.

[ odenwald - 35 - 11:37:40 ]
RE: [Renae-Renae/TheBridgeSchool] Why are the planets different sizes?
It has a lot to do with the physical conditions under which planets formed. We know that the range of sizes for large bodies in the solar system spans a big range. Earlyon, many of these bodies gobbled up each other by collisions, and what we now se is the result of that canibalism.

[ Sandy/NASAChatHost - 36 - 11:38:11 ]
RE: [Aaron/VanBurenmiddleschool-Mr.Doe/VanBurenMiddleSchool] Has anyboddy found any new planets?
Hi Aaron! Welcome to you and your fellow VanBuren Middle School classmates (and Mr. Doe)!

[ odenwald - 37 - 11:38:30 ]
RE: [Aaron/VanBurenmiddleschool-Mr.Doe/VanBurenMiddleSchool] Has anyboddy found any new planets?
yes...the current count of known planets outside our soolar system is now 17, and these are spread among something line 10 other stars near the sun.

[ StenOdenwald/Astronomer - 41 - 11:39:52 ]
RE: [Stephanie/Edmonton] How many languages do you speak?
I speak English and Swedish, and I can write in 4 different computer languages.

[ StenOdenwald/Astronomer - 43 - 11:41:22 ]
RE: [Renae-Renae/TheBridgeSchool] Why does Saturn have rings around it?
So do Jupiter, Uranus and Neptune, its just that saturns rings are brighter and denser. We dont exactly know why rings get formed, but then, most collections of matter that spin too fast form flattened disks, and rings are 'just' a special case of an orbiting disk.

[ StenOdenwald/Astronomer - 47 - 11:42:32 ]
RE: [Matt/VanBurenmiddleschool-Mr.Doe/VanBurenMiddleSchool] over there at nasa have you all found any extraterretrials? Don't lie to me I know!!!!!!!!!!!!!!
No we haven't. You have to understand that what you see in the movies and on TV is not a documentary. X-files is not the real world...but it is pretty entertaining!

[ StenOdenwald/Astronomer - 48 - 11:43:59 ]
RE: [Raquel/SP/Brazil] Why can't our Universe be shrinking ? Maybe the redshift that we observe was "formed" millions of years ago and at this moment a blueshift "is being produced" but we had no time to get it.
Its hard to answer a proposal like this because you cannot provide any physical or mathematical justification for such an idea. It has to be testable, and falsifiable to be science.

[ StenOdenwald/Astronomer - 50 - 11:44:57 ]
RE: [Stephanie/Edmonton] Is a white hole like Star Trek's "wormhole"?
No...white holes are just another form of black hole, but with time running in reverse. Wormholes are very different mathematical beasts..

[ StenOdenwald/Astronomer - 52 - 11:46:20 ]
RE: [Aaron/VanBurenmiddleschool-Mr.Doe/VanBurenMiddleSchool] Can you name those extra 8 planets?
For a start, visit http://www2.ari.net/home/odenwald/cafe.html and click on Ask the Astronomer. In the FAQ topic index you will see 'Other Planetary Systems' There are many FAQs there, with links to places that keep current counts.

[ StenOdenwald/Astronomer - 55 - 11:47:59 ]
RE: [Renae-Renae/TheBridgeSchool] Why do flares come out of the sun?
The main idea behind solar flares is that the magnetic field near the surface of the sun gets badly tangled up and decides to reconnect itself to maje a simpler field geometry. This releases a lot of energy as curents of charged particles are forced to flow to 'short circuit' portions of the field to make the new field shape.

[ StenOdenwald/Astronomer - 59 - 11:49:39 ]
RE: [matt/VanBurenmiddleschool-Mr.Doe/VanBurenMiddleSchool] have you found sub-atomic particles? if so is there any chance of making a sub-atom bomb?
Electrons are 'sub-atomic' particles...this fact alone doesnt mean you can create a special kind of bomb. generally, fusion bombs dont rely on sub-atomic physics beyond what protons and neutrons require in the nuclear regions of atoms.

[ Sandy/NASAChatHost - 60 - 11:50:31 ]
EVERYONE: There are about 10 minutes left in today's chat with Sten. At the end of the chat, please let us know how the Quest Project is doing with its chats by filling out a short survey at: http://quest.arc.nasa.gov/qchats/qchat-surveys Thanks :-)

[ StenOdenwald/Astronomer - 62 - 11:51:13 ]
RE: [Stephanie/Edmonton] Is it actually possible to have 12 dimensions?
We dont know...it is purely a mathematical speculation based on some theories that physicists come up with to explain the patterns they see in high-energy physics. Some theorists, however, think that we can explain all we need to with just the ordinary four dimensions of space and time. the rest are just 'book keeping' and go away after a calculation runs its course.

[ StenOdenwald/Astronomer - 63 - 11:52:36 ]
RE: [Aaron/VanBurenmiddleschool-Mr.Doe/VanBurenMiddleSchool] Do you think that ther are any life forms on those other eight planets?
We have no idea...most of the planets seem to come so close to their stars that the planets must get nearly as hot as boiling water...we dont know all the different ways that life can arise...yet!

[ StenOdenwald/Astronomer - 64 - 11:53:12 ]
RE: [Raquel/SP/Brazil] Have you heard of superluminal waves ? Are they real ?
I have never heard of such things...can you tell me what was being described?

[ StenOdenwald/Astronomer - 66 - 11:54:58 ]
RE: [Stephanie/Edmonton] Why is the corona of the sun hotter than its center?
According to the recent results from SOHO last year, the surface is covered by a changing 'magnetic carpet' and as these very small magnetic field loops merge together, they release a great deal of energy which heats the layers of the sun above them all the way into the corona. the corona is at a temperature of 2 million degrees while the surface is only at 5,770 degrees.

[ StenOdenwald/Astronomer - 67 - 11:55:39 ]
RE: [matt/VanBurenmiddleschool-Mr.Doe/VanBurenMiddleSchool] how's that mars trip goin' are there gonna be people over there in century 21?
Probably yes...but it will be a hazerdous voyage!

[ StenOdenwald/Astronomer - 70 - 11:56:12 ]
RE: [Aaron/VanBurenmiddleschool-Mr.Doe/VanBurenMiddleSchool] Do you think that the universe is just like a galaxy , lots and lots of them , but bigger?
No, the physics are completely different and do not scale geometrically like that.

[ StenOdenwald/Astronomer - 72 - 11:57:08 ]
RE: [Aaron/VanBurenmiddleschool-Mr.Doe/VanBurenMiddleSchool] do you beleive in the theory of relativity? how familiar are you with steven hawking's theorys?
relativity is not a matter of 'belief'...it is not a matter of 'opinion', there is simply too much evidence in favor of it.

[ StenOdenwald/Astronomer - 74 - 11:58:05 ]
RE: [Raquel/SP/Brazil] Superluminal waves travel faster than light ( 6 times the light speed ) They were obtained by a German physicist ( Günter Numtiz, I think ). But it is against relativity !
many quantum mechanical processes occur at faster than light speeds, and relativity is obeyed because you cannot use the information that is transmitted.

[ StenOdenwald/Astronomer - 81 - 12:02:01 ]
RE: [Aaron/VanBurenmiddleschool-Mr.Doe/VanBurenMiddleSchool] Is there any way that a comet is going to hit us and we are all going to die?
NO. Any such comet would already be know to us that would be large enoug to do that damage. We still have to be on the look out though!!

[ StenOdenwald/Astronomer - 83 - 12:03:23 ]
FOlks! I ned to get going to another conference right now...It has been fun chatting with you all today, please come back next time if you feel there were more things you wanted to discuss!! By!

[ Sandy/NASAChatHost - 84 - 12:03:52 ]
EVERYONE: IT's time for Sten to get back to his real work of the day, so we'll have to call it quits until next week! Please join us again: Same time, Same place. But don't forget to register :-) Thanks for all of your great questions today. Please fill out the chat survey! Thank you :-)

[ Sandy/NASAChatHost - 86 - 12:05:50 ]
RE: [Raquel/SP/Brazil] Thank you very much, Dr. Sten !
Goodbye Raquel! Please join in Sten's chat again next Thursday! You asked some awesome questions today :-)