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What is the possibility of life other planets?

In order for life (in the form that is most familiar to us) to evolve on a planet, scientists believe that the planet must be warm enough to contain at least some liquid water, but not so hot that all of the water turns to vapor, as appears to be... More

Why is water so important for life?

Every known form of life on earth, from the largest mammals to the smallest microbes, relies on water. Why? Because water is an extraordinarily versatile molecule - it's the perfect liquid medium in which to dissolve nutrients for ingestion or wastes for excretion, to transport important chemicals or... More

Does the government have aliens in area 51?

Probably not, considering the fact that the chunk of Nevada desert known as "Area 51" ceased to exist several decades ago. Many people would like to think so, however, given the popular use of "Area 51" for a backdrop in countless science-fiction stories, TV series, movies, and tabloid newspapers.... More

What would earth look like without water on it? What would be the shape of the 'piece of rock' that would remain?

If you started with the planet as it is today and removed the water suddenly, there would be some rebound in the ocean basins in response to to removal of the pressure of the water. More generally, however, many geologists think that in the absence of water there would be... More

What is the temperature of Europa (one of Jupiter's moons)?

Like any planet or moon, the temperature depends on where you are. On Europa this can range from as low as -200 C at the surface near the poles to a high in the deep interior that may approach the melting temperature of rocks (above 1000 C). Within its large... More

Has NASA any had UFO problems ?(i'm doing a school project on them)

No, I can't imagine that NASA would have any problems with something that doesn't exist. The sad thing about UFO reports is that they distract so many people from understanding and enjoying real science. (There is a lot of nonsense on the Internet about UFOs, but I do recommend the... More

How long have humans existed on Earth?

Human have existed for roughly half a million years, but this answer depends on the exact definition of "human". Fossil evidence shows that several human-like lineages developed during the past million years or so. >From fossils, the appearance of Homo sapiens is dated at about half a million years, and... More

Have there been sightings of UFO's while you are in space? Also i would like to know if you have ever seen an alien?

The answer to both questions is No. As discussed here previously (check for UFO entries by using the search engine), no astronauts have seen UFOs. Certainly I have never seen an alien, nor have I come across any convincing evidence that anyone else has either. The modern myth of aliens... More

Is area 51 hiding u.f.o ?

No. Area 51 is an obsolete designation for a U.S. Air Force airfield near Las Vegas, Nevada. It is located adjacent to the Nevada Test Range, which was once used for nuclear weapon tests. This area has been used for testing experimental aircraft, which may have been interpreted as UFOs,... More

What is Planet Nibiru/Eris ? Is it going to flyby Earth in 2012 ? Are we going to survive the flyby ?

You seem to have fallen for the "Nibiru hoax". Eris is a dwarf planet in the outer solar system, a bit larger than Pluto, discovered in 2003 (see Wikipedia article at http://en.wikipedia.org/wiki/Eris_(dwarf_planet)). Nibiru does not exist; it is a hoax, and certainly it has nothing to do with Eris. Wikipedia... More

Is there a planet Nibiru that will pretty much destroy earth in 2012? I watched a video about it last night and I freaked out so bad i was shaking and crying. Is our world coming to an end in 2012? If so... why cant we just blow the thing up and call it a day?

I am really sorry that these crazy Nibiru claims have upset you. I don't want to keep answering these questions about Nibiru, but let me say once more as clearly as I can, for you and the other questioners: Nibiru does not exist. NASA has never discovered or detected Nibiru... More

Nibiru Redux: Six recent questions about Nibiru: (1) I have found a lot of stuff about a so called planet. Planet x or nibiru. It anything they say possible like revolving around the sun clockwise and it has been said that its orbit is way far out past Pluto. Also there are statements that it has a 3600 year orbit around the sun an that is is supposed to return in the near future. Is this possible at all? It sounds fishy to me, but there are supposed pics of it and a lot of scientist talk about it. I even wikipedia searched it. I would just like to find out some info please. (2) Nibiru does exist and I can prove it. Nibiru is in the old testament Exodus 6:4. and you are watching Nibiru from a lab on the south pole. also I have images from a telescope of Nibiru. and people from the southern hemisphere can see Nibiru in the daytime. is that proof enough for you? (3) many signs tell that something big is out there coming and why wouldn't it be true about nibiru / planet x there is a lot of fact historical and scientific but i do understand your awnser but why build a telescope at the south pole an photos and such with this redish dwarf star moving fast in 1983 it was 50 billion miles away and 10 years later it is alot closer is it hiding behind the sun i know you all dont want to start a world wide panic. (4) I read were you said that Nibiru is a hoax. My question to you is why would anyone let the american population know about such a catastrophy? Isnt it the governments job to keep the population at ease? (5) You say Nibiru is a hoax, and no such planet exists, but is Nibiru not Eris? (6) What is this a picture of? http://www.greatdreams.com/nibiru-possible.jpg It's said to be Nibiru, but as you say Nibiru is a hoax. so what is this really a photo of?

I hope this is my last comment on the Nibiru hoax, but questions like the above six keep coming in. Most of the entries on the Internet about Nibiru are false. Wikipedia has it correct when they write that "Nibiru is a name in Sumerian, Babylonian astrology associated with the... More

Now if the Nibiru topic is a hoax, then what are the infrared images of the alleged Nibiru??? And i also heard that NASA saw it with IRAS and reported it and all that. Why does NASA deny anything about it instead of telling the public so (if Nibiru is in fact a hoax) they dont take durastic measures such as my family was planning on doing.I need more proof that Nibiru is a hoax because the government and NASA are keeping to much from us for us to make full judgement on it....

I really am sorry that you have taken the Nibiru hoax seriously, and that this hoax is causing you and your family distress. This Nibiru stuff is all pure fiction, without any core of fact or truth. Specifically (1) The are no infrared images of Nibiru -- period. (2) IRAS... More

When most of the planets align in 2012 and planet earth is in the center of the milky way,what will the effects of this be on planet earth? could it cause a pole shift,if so what could we expect.

There is no planet alignment in 2012 or any other time in the next several decades. As to the Earth being in the center of the Milky Way, I don't know what this phrase means, If you are referring to the Milky Way Galaxy, we are rather far toward the... More

Can you please explain the polar shift theory? Supposedly the earth's crust does a 180 degree rotation around the core in a matter of days if not hours. Furthermore, this is stated to be a regular occurrence in Earth's geologic history and has to do with our solar system dipping beneath the galactic equator. Is there any merit to it?

I will try to explain. This is one of the craziest lies that is being promulgated by the 2012 conspiracy theorists -- worse in many ways than the Nibiru hoax. It is totally absurd, and completely untrue, but still the story spreads and is frightening people. First, on the matter of a sudden reversal... More

Solar flares, how dangerous are they? is there evidence of them being dangerous to the earth in the past? I'm always seeing stories on these sites that a major solar flare is coming and it will burn up half the earth. Also is our solar system moving closer together or further apart? For instance, is there any evidence that once in the early days of our solar system that earth was possibly as Venus is now, and Mars was as earth is now.

Solar flares eject high-energy plasma (atomic particles) into space, which could be very dangerous (for a few hours) to any astronauts outside the the Earth's magnetosphere. In the future, astronauts who spend long periods of time on the Moon or traveling to asteroids or to Mars will need protection against occasional large solar flares.... More

Confused about 2012 "Powerful Solar Storm Could Shut Down U.S. for Months" is a report on the Fox News website. They stated the report was commissioned and paid for by NASA. It was reported by The National Academy of Sciences and includes a comment by Richard Fisher, director of the Heliophysics division at NASA. If nothing is going to happen as a result of the event in 2012, why would NASA allow such nonsense to be reported.

There is nothing wrong with the National Research Council report on heliophysics, and NASA is very pleased with it. As you note, this report includes a worst-case analysis of what could happen today if there were a repetition of the biggest solar storm ever recorded (in 1859). The problem is... More

NASA has denied the existence of Aliens, and NASA claims that there is no proof that the aliens have ever visited the earth, my question will be regarding the egyptian pyramids, do you seriously think that people living thousands of yours BC have build the great pyramids? One more question is how does NASA explain the "face" and the "pyramids" found at Cydonia, in planet MARS.

Unfortunately, quite a few people have fallen for these alien-pseudoscience claims, so I will briefly answer your questions, even though they are not directly related to astrobiology. (1) NASA does not deny the existence of aliens. Most astrobiologists anticipate billions of inhabited planets, including many that are the home to... More

Can you provide an update on Nibiru? Some people still claim that it is hiding behind the sun and can be photographed with small cameras but not seen directly. Others predict that it will be visible to everyone this spring. And what about the alignment of the sun with the center of the Milky Way Galaxy? Is there any truth to these claims?

This is a good time to answer these questions, since on about December 21 of each year the Sun is approximately in the direction of the galactic center. Do you feel any mysterious forces this week? Is the Earth losing it bearings and changing its rotation? No, of course not. And the situation on... More

A statement of yours caught my eye: "As far as the safety of the Earth is concerned, the important threats are from global warming and loss of biological diversity." I sincerely hope that you are not referring to AGW. I mention this because AGW is a hoax that is far worse than a fictional planet Nibiru.

I don't understand how you or any intelligent person can call AGW (human caused global warming) a hoax. Maybe you aren't paying attention to the science. (1) There is no question that the Earth has been warming over the past 50 years at an unprecedented rate, as shown by temperature measurements in the atmosphere,... More

I have recently read on the Sky News website about a star known as T Pyxidis it is going to explode and could wipe out Planet Earth please could you put me out of my misery and tell me if this is going to happen and when?

This is a question that is easily answered using Wikipedia. T Pyxidis is a binary star system in the constellation Pyxis at about 3260 light years from Earth. It contains a sun-like star and a white dwarf. Because of the strong gravity of the white dwarf, it draws matter from... More

How can you claim "Aliens" do not exist. Over 100's of years we have found (flying projectiles, ships, bodies, readings, and other intriguing step notes) into what could be aliens. Where is your proof that Aliens do not exist.

No astrobiologists say that aliens do not exist. We expect lots of planetary systems to be inhabited with some form of life. All we say is that we have found no convincing evidence of life anywhere beyond Earth. The other things you mention relating to intelligent aliens visiting Earth are... More

Is global warming is real? Because my science teacher says its all fake.

I am sorry to say that your science teacher is wrong. Global warming is both real and threatening. As more and more data have been gathered, the world’s atmospheric and climate scientists have become convinced of this fact. The only reason I can imagine that your science teacher disputes this... More

On the History Channel there is a show on now call Apocalypse Island and it says explorer Jim Turner finds an artifact on a remote island in the Pacific Ocean that he believes is a clue about the Mayan apocalyptic predictions for 2012. Is this true?

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Is Jeff Turner smoking too much when it comes to his theory about the Mayan monument on Apocalypse Island?

The show Apocalypse Island is fiction. Fiction, by definition, is not true. Others have asked whether things in the movie 2012 or the fake website that supports the movie (The Institute for Human Continuity) are true, but these are fiction also. Other works of fiction that have fooled people are... More

I have been watching a show called Conspiracy Theory hosted by Jesse Ventura, and he did a show on 2012. According to them, they say that Nasa is predicting that something will happen in 2012!

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Have u ever watched a show on true tv called conspiracy theory with jesse ventura,?he says nasa knows about a major solar storm that gonna hit us in 2012 and wipe out humanity, and u guys are helping cover it up, ? if this is true why isent anyone telling us? I think we deserve the facts now.

Jesse Ventura is no scientist, he is not associated with NASA, and the things you report he said are not true. My guess is that this sort of manipulation for profit will grow right up until the end of 2012. My concern is how many people are gullible enough to... More

You stated that "Most of the observed temperature variations up to beginning of the twentieth century can be traced to small changes in solar output, plus changes in the Earth’s orbit, plus short-term cooling associated with large volcanic eruptions..." I understand the other causes but haven't heard very much about the Earth's orbit changing. How is it changing and how has it affected our climate?

There are slow changes in the eccentricity of the orbit and the tilt of the Earth’s axis. These matter for the climate of the planet even though they do not change the total amount of sunlight reaching us, because it makes a difference where the sunlight falls (near the poles... More

Some scientists are saying that all ice on the artic ocean will be gone...could it happen so fast?....i thought that the water level would increase with 1 meter or 2 before 2100 but not faster -- is that fake or a hoax?....and i read that the movie "an inconvenient truth" is forbidden to be shown in schools because it contains many errors -- is that true?.

In the past two decades the Arctic ice has thinned and receded. One consequence is the opening of the Northwest Passage to ships for the first time in human history. Current predictions are that within another two decades the Arctic Sea may be ice-free at the end of summer. However,... More

I just wanted to know if the scientists could predict wrong of when the sun goes supernova. The reason why I ask this is because it says that in the movie The Knowing. And there's also a movie called 2012: Supernova which talks about that, and the regular movie 2012. Does this all tie together somehow?

I keep asking people to distinguish between fact and fiction. The three movies you mention are pure fiction, completely unconnected to scientific reality. There have been lots of science fiction films made, some good and some bad as entertainment, but few of them make any attempt to get the science... More

Could there be life on the moon Pandora?

Pandora is a very small icy moon of Saturn, about 100 km long, discovered by the Voyager spacecraft in 1980. See Wikipedia at [http://en.wikipedia.org/wiki/Pandora_(moon)]. I can hardly think of a less likely place to look for life. Unfortunately, you may be thinking of the fictional location featured in the movie... More

I know we have a corupt government, and I know nasa works closley with the government. If they told you to keep quiet about 2012 to keep panic down would you still tell the people the truth? As a concerned citizen I feel compelled to ask the question.

I am sorry you feel this way about your government and are willing, apparently, to think it is trying to deceive you. NASA is a part of the government (an Executive Agency). I strongly disagree with your statement that we have a corrupt government. You may not agree with some... More