Jump to content

Recommended Posts

  • Replies 274
  • Created
  • Last Reply

Top Posters In This Topic

Ahh, Venus. No moons, no rings, a little bit smaller then Earth. The surface temperature is about 750F, hotter then Mercury. The pressure on the surface is 90 times higher then on Earth, and the atmosphere contains sulfuric acid. If you were there, it would be a race to see whether you died from being crushed, burned, or dissolved. Most likely all three would happen at the same time and you would be reduced to a little pile of dust. Any water that was originally on the surface has since evaporated and the extreme greenhouse effect is responsible for the extreme pressure and heat. The thick atmosphere caused by the greenhouse effect is so reflective that it makes Venus the brightest object in the sky after the sun and moon. We can look forward to a future where Earth has the same characteristics as Venus unless we can stop the greenhouse effect from taking hold here.http://en.wikipedia.org/wiki/Venushttp://en.wikipedia.org/wiki/Colonization_of_Venus

Link to post
Share on other sites

The greenhouse effect creeps me out, I hate fossil fuels, but they're our power resource. I've heard solar powered cars is very expensive, unless it was just a rumor and they weren't even invented yet.As for Venus, I know about the surfuric acid in the atmosphere, and it's the hottest planet (I think) because of the mass amount of carbon (dioxide?) in the atmosphere as well. I didn't know it doesn't have any moons, thanks.I'm reading about Ceres, Pluto, and 2003 UB313, well I wanted to know about the new "dwarf planets" in the Solar System, but I wanted to know more about the definition of "dwarf planet", what's the difference.I found Wiki confusing, so can you explain to me what "does not clear the neighbourhood", when they refer to a "dwarf planet" not "clearing the neighbourhood"?Also, has 2003 UB313 become Eris, or is Eris in a different Solar System?Also, I hate to be asking so much but do you mind explaining the different categories of Dwarfs?I find there's so much, in such confusing terms on Wiki, or I just might not be reading them carefully enough, but hopefully you guys could make this easier.The greenhouse effect creeps me out, I hate fossil fuels, but they're our power resource. I've heard solar powered cars is very expensive, unless it was just a rumor and they weren't even invented yet.As for Venus, I know about the surfuric acid in the atmosphere, and it's the hottest planet (I think) because of the mass amount of carbon (dioxide?) in the atmosphere as well. I didn't know it doesn't have any moons, thanks.I'm reading about Ceres, Pluto, and 2003 UB313, well I wanted to know about the new "dwarf planets" in the Solar System, but I wanted to know more about the definition of "dwarf planet", what's the difference.I found Wiki confusing, so can you explain to me what "does not clear the neighbourhood", when they refer to a "dwarf planet" not "clearing the neighbourhood"?Also, has 2003 UB313 become Eris, or is Eris in a different Solar System?Also, I hate to be asking so much but do you mind explaining the different categories of Dwarfs?I find there's so much, in such confusing terms on Wiki, or I just might not be reading them carefully enough, but hopefully you guys could make this easier.http://en.wikipedia.org/wiki/Dwarf_planet#...f_dwarf_planets

Link to post
Share on other sites

Solar power is expensive and inefficient at this point. Solar cells have usually converted something like 8-10% of solar energy into electrical power, the rest is lost in heat and transfer. But I heard that recently some cells were developed that could convert 40% of the energy into power, and if that's true then the cost will come down to the point that solar power plants are more feasible. Solar cars have been limited to concept cars and racing cars, but at some point we could probably have solar cells mounted on existing electrical cars to recharge the batteries, if the efficiency gets high enough.When they talk about a dwarf planet and not being able to clear the neighborhood, they are talking about the gravity that the body produces. Earth is not a dwarf planet, if any objects get in the same orbital path as the earth, the gravity from the earth will pull them into the atmosphere. Ceres, on the other hand, is right in the middle of the asteroid belt. There are thousands of other objects in the same orbit as Ceres, but Ceres does not have enough gravity to pull them in. That's what they mean by clearing the neighborhood, they are saying that in order to be a planet instead of a dwarf planet, it needs to have gravitational control over its orbit and capture anything else that's in the same orbit.As for Eris, the only planets we are aware of in other solar systems are enormous gas giants that orbit very close to their parent stars. I believe the only image we have of a planet in other solar system is this one:http://antwrp.gsfc.nasa.gov/apod/ap050510.htmlWe can't see anything as small as Eris from that far away, in fact we can't even see anything as small as Earth. The planet in that image above is about 5 times larger then Jupiter, which is the largest planet in our system. If a planet gets up to about 60 times the mass of Jupiter, then it has enough mass to start fusion and form a star. Eris is located beyond the orbit of Neptune, so they call it a trans-Neptunian object. Beyond Neptune is the Kuiper belt, then the scattered disc, then the Oort cloud. All of these contain icy chunks and things like that. Eris is one of them, and it's even larger then Pluto is. 2003 UB313 is the same object as Eris. If you ever heard the media mention Xena, Eris and Xena are also the same object.As for the different categories of dwarfs, there are only three planet classifications. They are "planet", "dwarf planet", and "small solar system body". The last one is an object that is not large enough to be a sphere. There are also different types of dwarf stars, like red dwarfs and brown dwarfs. What makes a certain type of star is related to the age of the star and the amount of mass. Stars with more mass glow brighter and burn out faster then stars with less mass.

Link to post
Share on other sites

Thanks, I was confused with the three names "Xena", "2003 UB313" and "Eris", so now that I know they are all the same thing that's great.So Ceres is in the Asteroid Belt, how big is it, and has it ever been in risk of damage?Also, how big is the Asteroid Belt?You explained this to me, but I already early started looking up trans-neptunian objects, the Kuiper Belt, the Scattered Disk, and the Oort Cloud. If you could give me some information on how these fields of space are, and what else they found in them, that would be great.Your definition of "Clearing the Neighbourhood" really maked a lot of sense.Also, I heard people say Pluto used to be star, I don't think so, but is this correct?___EditI figured out that the Oort Cloud is a big field of Comets, that's about 2000 times the distance that Pluto is from the Sun.For a new question, is Proxima Centauri a base for another Solar System?

Link to post
Share on other sites

Ceres isn't all that big in the grand scheme. It's the largest asteroid, but still not very big. On the wikipedia page there is a picture comparing it to the moon:http://en.wikipedia.org/wiki/Ceres_(dwarf_planet)I guess "risk of damage" is relative. Everything is constantly getting hit by things coming in from space, but the impacts aren't big enough to destroy it. A lot of the dust we see here on earth came from objects burning up in the atmosphere. I guess Ceres is fairly safe, despite being in the asteroid belt.Speaking of the asteroid belt, there is a great image on the wikipedia page:http://en.wikipedia.org/wiki/Asteroid_beltYou can see the distribution of asteroids between Mars and Jupiter. It also really illustrates the "clearing the neghborhood" thing, you can see the interior planets don't have a lot of debris around them, and the area around Jupiter is pretty clear too. But nothing in the asteroid belt has the gravity to pull it all together, so that's why there are so many objects there.The Kuiper belt and beyond is pretty much a big cloud of rock and ice and orbits the sun. Comets come from this area. The comets we see have an orbit that is elongated enough that the comets shoot out of the Kuiper belt area and fly towards the sun, then the gravity whips them around and they shoot back out into the Kuiper belt. I know Halley's comet, for example, has an orbit of 75 years or so.And no, Pluto did not used to be a star. It is way too small, it does not have the mass that is required to begin fusion. Even Jupiter is way too small. An object needs about .05 times the mass of the sun to start the fusion process and burn. So Jupiter would need to be about 60 times more massive to trigger fusion.I don't know what you mean by Proxima Centauri being a base, but any star could feasibly have planets around it. The whole formation process of a star has side effects that cause planets to form, so anywhere a star could form a planet could also form.

Link to post
Share on other sites
You can see the distribution of asteroids between Mars and Jupiter. It also really illustrates the "clearing the neghborhood" thing, you can see the interior planets don't have a lot of debris around them, and the area around Jupiter is pretty clear too. But nothing in the asteroid belt has the gravity to pull it all together, so that's why there are so many objects there.
I beat you to it again. :)Just before you posted I had a look at it, it's really neat, and big.So Ceres...for more than a century we actually thought it was a planet....that just shows you the amount we've gained in technology.The picture gave me a good idea what it's like too, in mass.I figured because of the whole fusion process that Pluto wouldn't be a star, but I swear I heard people go on about how it used to be a star. I thought maybe it was damaged and crumpled, but I guess that was pretty inaccurate. Now that I think of it, any star can have things orbiting around it, because supposively the stars make the planets by releasing carbon and hydrogen, and other things... if you could fill me in on the whole process that would be great, of planets forming from the stars.What are Sedna and Orcus categorized as?Solar System Objects (Orbiters)?
Link to post
Share on other sites

Sedna and Orcus are both just trans-Neptunian objects, I guess there are different types but the distinctions between them are fairly arbitrary. Here is a picture comparing the 8 largest known TNOs:http://en.wikipedia.org/wiki/Image:EightTNOs.pngAs far as star and planet formation goes, it's not really accurate to say that planets form from stars, they sort of just both form from the same stuff. It starts with a cloud of gas and dust. Over time, it will start to condense in the center of the cloud where the gravity is centered, and more and more mass will be drawn in. The other matter in the cloud will start to orbit around the middle of the cloud. Once the center of the cloud reaches a critical mass, the atoms will be so compressed that they will start to fuse together and fusion will change the ball of mass into a burning star, where the hydrogen atoms fuse together to become helium and release energy. But stars do not release hydrogen (unless they explode), they burn it. Once a star's hydrogen fuel runs out, the explosive force that keeps the star round ceases and it collapses and explodes. The explosion of a star is strong enough that every element is produced. If the star has barely enough matter to be a star in the first place, then instead of exploding it might just burn out and condense into a brown dwarf or another small, dense object.Once the star is formed, the rest of the cloud will continue to orbit. As it orbits faster and faster, the cloud will flatten to form a disc. They call it an accretion disc or protoplanetary disc, and we have pictures of discs with faint stars in the middle starting up. Here is a good shot of the disc around Fomalhaut:http://en.wikipedia.org/wiki/FomalhautThe same process happens in the disc to form planets that happened in the cloud to form the star at the middle. At various distances in the disc, matter will get concentrated into one spot because of gravitational pull. As more and more matter gets drawn to that spot, it will combine and will form a planet. The type of planet depends on the location in the disk. Heavier elements like metals and rock tend to be drawn towards the middle of the disc, so planets that form in the interior are usually rocky planets (Mercury, Venus, Earth, Mars). Gas and dust are less dense and so they tend to be farther out in the disc, so the planets that form farther out are composed primarily of gas (Jupiter, Saturn, Uranus, Neptune). If there is enough matter in the disc to form a planet that gets large enough to kick off fusion, then the system will become a multiple-star system. There are several binary systems with 2 stars we know about, and several systems with more then 2. Obviously some regions in the disc contain less matter then others, so there may be parts in the disc where planets will never form. That would be the asteroid belt and the Kuiper belt, Oort cloud, etc. There are small objects, but they haven't had time yet to condense into a larger object. Given another couple billion years, we might have another rocky planet between Mars and Jupiter and a large rocky, icy planet beyond Neptune.

Link to post
Share on other sites

Doesn't the sun release various gases that are used in the formation of the planets around it. What your saying makes perfect sense, and you're right, but can you explain in more detail because I thought it said something about the sun having to do with the product of gases and materials for the planets, because I just watched BBC's Sky at Night, which explains the formation of distant galaxies and solar systems, with outer-solar planets, and it's also a special on Venus of which I bought, and it also includes some interesting photographs, which I'll show.I only saved a few, but if you would like to see more I could. i'm not sure if the quality will be as clear because ImageShack compresses it, but you'll get the idea.The is the map that the rover took on mars, or a small portion.mars0dp.pngTwo smaller premature galaxies forming into one. That's why what you told me justsomeguy, is true, but the sun does play a part other than a pull.multigalaxyform1am.pngHere's just a small picture comparing Venus and Earth. A goal is for man to visit Venus, although it seems pretty hard now, they're thinking of it as a smaller goal after Mars.I've figured out that the Carbon Dioxide is coming from the water that was steamed away, turning into oxygen and hydrogen into the atmosphere, where most of the hydrogen went out into space. That's what BBC said anyways, but any better explanations/tips would be great.venusearth5pf.pngNow, this is the mapping of Venus' surface which was obviously computer enhanced, but this is an idea of what it would look like.Venus has strange deep valleys that are usually eroded by water, but there isn't supposed to be any water, and lava usually transforms into molten rock before it can get any depth. That's one of the mysteries.venussurface9ky.pngYeah, so for the distant planets go, outside of our Solar System, we're finding mostly Gas Giants like Jupiter, that are easy to locate, but they're also very close to the sun, and like five times as big, which is very fascinating.Using the wasp system, which I think traps light waves, we can find planets like Earth possibly.I don't know a whole lot about all of this, but it just started fascinating me and I'd like to know more.

Link to post
Share on other sites

Most of the matter that the sun gives off is in the form of a coronal mass ejection. I'm sure you've seen pictures of them, but the CMEs don't have enough mass to really contribute much to something like a planet, and most of the matter that gets ejected ends up getting drawn back into the star. You can see what I mean here:http://en.wikipedia.org/wiki/Coronal_mass_ejectionThe ejections go out a long way, but most of the matter loops back into the sun. Also, most of the matter is plasma instead of elements like helium and oxygen that would be involved in planet formation. But stars typically don't contribute much matter to their orbiting planets, in fact more often the planets get their matter sucked into the parent star. You can see that concept here, which is a depiction of a black hole sucking in matter from a nearby star, but you can think of the same scenario where a star is sucking in matter from a nearby gas giant planet.http://en.wikipedia.org/wiki/Image:Accretion_disk.jpgThe key is the gravity. If a nearby star exerts more gravity on a planet's upper atmosphere then the gravity of the planet itself, then the atmosphere will be sucked into the star. The opposite doesn't hold true very often, where a planet would exert more gravity on the upper atmosphere of a star then the gravity of the star itself. The only case that might be true is if the sun were to turn into a red supergiant (which will eventually happen), and the outer surface of the sun stretches out near Jupiter, then it might be the case that Jupiter's gravity on those outer layers is stronger then the sun's gravity because it would be so close to Jupiter. In that case, Jupiter might absorb a little bit of the outer layers of the sun, but that wouldn't last very long because the sun would expire and rapidly shrink back in on itself. And then it would explode. And it would scatter all kinds of elements all over the place.

Link to post
Share on other sites

Hallo, I have been reading some of this topic and found it really intresting, I know that its a bit off topic, but its in the same theme of the 'unknown' so as to speak.I read near the start of this topic that there are two things man cannot imagine, I cant rember them now (:)) but i would also like to throw in this: Try to imagine a colour that has never been seen beforeIts not possible, or at least I couldnt manage it. The second thing is something I learned in a physics lesson at school that our teacher started going in to despite its irrelevance to the current topic. If you can think for a bit, why can two solid objects not pass through each other? Well every solid object (including man) is made up of insane amounts of atoms. In an atom you have, at the very center, a nucleus and also a space around the outside, inside the nucleus you have prtons (+ charged) and nuetrons (no charge). Then in the space around the outside of the nucleus you have electrons (- charge) it is the electrons around the outside of the atom that repel (same poles) that stop two objects passing through one another, they repel at HUMUNGUS forces and two electrons will never touch, but if two never touch, what happens when you put your finger on, say your computer desk.well at atomic measurements (really really really really really really small) there is actually a gap between your finger and the desk.There are, I find so many questions that arise from this, like if you think, paint doesnt touch a wall. We are (technically) floating as we walk. and the one that torubles me the most, how can you taste anything if your tastebuds dont touch food. It leaves me to wonder if the electrons some how inherit the properties of the object, thus, no object does anything. It is electrons that taste your food, electrons that have different frictions (rubber and Ice).Just thought I would throw in my knowleddge (very little :)) and if anything is incorrect or if this post was a total wase of time, blame modern education!!!,Knimbus

Link to post
Share on other sites

Knimbus, are you dutch (or from somewhere around the netherlands)? Just wondering :).My teacher told me in class something very interesting. A few years back a lab at Harvard did a test, they had a tube filled with some "special" material, it was close to 1-2 K. Basically really really cold. Then the shot some light through the tube (clear tube, mind you) and the people around it could actually see the light going through the tube (1.5 meters long). It took several minutes for the light to go through the whole thing, isn't that awesome? Instead of 3X10^8 m/s it went 1.5 m/min. 0.o Little bit of a difference there! Imagine what else we could do!!

Link to post
Share on other sites
Well every solid object (including man) is made up of insane amounts of atoms. In an atom you have, at the very center, a nucleus and also a space around the outside, inside the nucleus you have prtons (+ charged) and nuetrons (no charge). Then in the space around the outside of the nucleus you have electrons (- charge) it is the electrons around the outside of the atom that repel (same poles) that stop two objects passing through one another, they repel at HUMUNGUS forces and two electrons will never touch, but if two never touch, what happens when you put your finger on, say your computer desk.
Wait until you start learning about Quantum Mechanics and how it is theoretically possible, though highly improbable, that a person could walk through a wall or fall through the earth and how electrons may only exist because we think that they exist and we observe them to exist.
Link to post
Share on other sites

NASA has a series of telescopes that they refer to as the "Great Observatories". Hubble was the first of those, there are currently 3 others. Hubble is the only one that observes light in the visible spectrum, the other three observe gamma rays, X-rays, and infrared. Hubble was deployed in 1990, the Compton Gamma Ray Observatory was deployed in 1991, the Chandra X-ray Observatory was deployed in 1999, and the Spitzer Space Telescope was deployed in 2003.http://www.nasa.gov/audience/forstudents/p...atories_PS.htmlHubble's successor is the James Webb Space Telescope, which will be deployed in 2013. Apparently it will be far superior to Hubble and will look far more retarded, but unfortunately it only observes in infrared light, not visible. Even so, it should produce some very detailed images.http://en.wikipedia.org/wiki/James_Webb_Space_Telescope

Link to post
Share on other sites
http://en.wikipedia.org/wiki/Image:JWST.jpgIt looks like a high school science project. Apparently the sun shield on the thing is as large as a tennis court. Contrast that with Spitzer, which looks like a sweet doomsday cannon.http://en.wikipedia.org/wiki/Image:Spitzer...e_telescope.jpg
Link to post
Share on other sites
  • 3 weeks later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...