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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

What are the raw materials for DNA?

Deoxyribonucleic acid (DNA) is a long polymer composed of nucleotides. Each nucleotide is made up of a sugar, a base, and a phosphate group. At the level of atoms, the composition of DNA is mostly carbon, hydrogen, oxygen, and nitrogen (often called CHON) -- the basic elements of all organic... 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

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

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

What do you make of this theory that the Earth will be in direct alignment with the center of the Milky Way in December of 2012? There are many websites which list a series of events in our solar system, leading up to the alignment which will cause a catastrophic change in the Earth¹s rotation. I went to your Solar System Simulator at http://space.jpl.nasa.gov/ (Which is really cool by the way) and typed in a bunch of these dates. It looked to me like the Earth was still intact. Is this alignment with the center of the galaxy even provable?

You are correct, there is no planetary alignment in December 2012. As to "alignment with the center of the Milky Way" that is a meaningless phrase. It may sound scientific, but it is devoid of content. To put it bluntly, these claims on the Internet of alignments and catastrophe in December... More

Hi, i have a question about the sun alignment in the center of the galaxy in 2012. Will the sun be in the EXACT center of the galaxy? or just lined up/next to the center of the sun. If you can, can you explain this to me. (15 years old) Thank you very much.

I can't explain it because it is just an Internet hoax. There is no alignment with the center of the Galaxy in 2012 or any time. As to the Sun being in the center of the Galaxy, that it impossible; the Sun and solar system will always remain at about 30,000 light years... More

why does the Mayan calender say the world will end in 2012?i know you have answered the plant x question....however i have heard that they have been pretty accurate in the past with other planetary stuff ,did they use planets so much to date things? and does that make them better at understanding the solar system? so if they have predicted an end in 2012 will it happen ,how can you be sure you know more than they did?

Calendars exist for keeping track of the passage of time, not for predicting the future. The Mayan astronomers were clever, and they developed a very complex calendar. Ancient calendars are interesting to historians, but of course they cannot match the ability we have today to keep track of time, or the precision of 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

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

As the average 15 year old I find it difficult to understand your answers about the so called 2012 doomsday. I have heard many theories one saying that the U.S project Philladelphia or something traveled into the future and there was nothing left in 2012 the earth was destroyed. Could you give me the simple answer are we or are we not going to die in 2012 I would rather take my own life than suffer a doomsday. ..AND.. hello I am really scared with the news that the world is going to end on 12 21 2012....I have been looking it up to try to find some information that is from a valuable source. Please help me!!!!

I received these two questions within a few minutes of each other, and they make me angry at the liars and fools who keep posting claims of a 2012 doomsday. Nothing will happen in 2012. There is no planet Nibiru, no planet alignment, no crossing the celestial equator, no change... More

HERE ARE TWO RECENT QUESTIONS: When will NASA actually admit to the existence of Niburu? It is in the Bible! People all over the world have seen it and taken pictures themselves. We all know that the Summerian Astrologers were very advanced, They knew of Pluto before our astrologists did. Why does Nasa try to discredit the existance of a planet the Summerians had mapped out a long time ago? ALSO I believe that Nibiru planet exists. Why are all other planets in our solar system experiencing global warming? Why did we just setup a telescope in the most uninhabitable region of Antarctica, and what is it doing now? Why is there a giant gap in the Kuiper belt? Why is Norway building underground bunkers ready for 2011? There are two more questions; if you can find answers for these I will give you a billion dollers. What exactly did the IRAS find? Why did the IRAS leading scientist Gerry Neugebauer say 'all i can tell you is we don't know what it is'?

I receive questions like this every day, and they upset me. They suggest to me that you are falling for the big Nibiru hoax, and that you have lost your critical common sense. Also apparently you have not read the “Summary” under “Special Note” at the top of the Ask... More

David Morrison denied the galactic alignment of 2012 in one of his answers. My concern about this is in all of my research, both the doomsday yaysayers and naysayers have talked about this. Even those who say nothing is going to happen in 2012 as a result of the alignment or anything else admit that this alignment is going to happen.

Several people have written to question my statement that there is no alignment in December 2012. It would have been more accurate if I had said “no significant alignment” or “no unique alignment”. Every December the position of the Sun as seen from the Earth passes near the galactic center.... More

My question is about the Yellowstone volcano. I have read that this is a supervolcano, and should it blow, it would cause the destruction of the earth. Apparently, it erupts every 160,000 years or so, and it's been 166,000 years since the last eruption, so we are due - either tomorrow, in a hundred years, or perhaps thousands of years. So, I guess my question is, how truly dangerous is this volcano?

The numbers you heard are off: please use Wikipedia as a first reference to get the facts straight. The last three Yellowstone supervolcano eruptions were 2.1, 1.3, and 0.6 million years ago. The average interval is thus about 0.6-0.7 million years, not 160,000 years. The largest of these, the Huckleberry... More

I have been doing some calculations in regards to an asteroid named (4179) Toutatis. It appears to have a very close intersection with Earth on mid-December 2012. Are you able to detemine with more accuracy how close this asteroid will come to Earth and what chances that it will make contact? AND Comet 45p/honda-mrkos is due to pass within 0.06 AU in 2011. I keep reading about this comet’s erratic orbits. This would appear to be a very close visit by a comet; what are the risks from debris/radiation/flares/asteroids?

While the Earth is subject to rare impacts by comets and asteroids, there are no predictions of any impacts in this century (see the NASA impact hazard website at http://impact.arc.nasa.gov). Concerning asteroid Toutatis, the orbit is very well known because this asteroid has been tracked by radar as well as... More

I want to ask how did NASA lose the rocket blueprint to go to the moon. I always wonder since today rocket technology is far more advanced then it was 40 years ago, and has there been research on anti gravity

AND

You wrote that we no longer have the capability to send astronauts to the Moon. Does this mean that the Apollo Program was a hoax too?

Losing the Moon rocket blueprints is an urban legend. The reason we could not duplicate the Saturn rockets that took astronauts to the Moon in the Apollo program is that the parts are no longer available, and many of the companies that built the Apollo hardware are no longer in... More

My question concerns the significance of life's existence on Earth and whether its simply an accidental byproduct of the Universe and could easily have not occurred, or if the Universe was designed to produce life.

Yours is a difficult question because astrobiologists do not understand exactly how life formed on Earth or elsewhere. In a trivial sense yes, the universe must be friendly to life or we would not be here to ask the question. But that would indicate that the universe allows life, not... More

Is the Doomsday 2012 hoax being covered by the newspapers and other traditional media?

Stories about 2012 are beginning to appear, stimulated by the opening of the movie 2012 on November 13, and also my own answers in Ask an Astrobiologist. The entire “20 questions” summary from this astrobiology webpage is printed in Skeptic Magazine this month (as the cover story).

Joel... More

On global warming, I gather you are a believer in man made warming as opposed to natural climate cycles. C02 is increasing but makes up a very small percent of greenhouse gases with the most abundant being water vapor. Here are a few questions I have. One I have read that the temperatures in the medevil times were warmer than today (pre fossil fuels); how can this be explained if not for cyclical temp patterns? Secondly with the C02 we are producing, why would the gov't just outlaw the production of it by 2030 as opposed to saying it is bad and proposing a cap-and-trade system? Sounds like a tax scheme.

I am sorry to see you repeating the disinformation that is being circulated by the global warming deniers. Specifically, you suggest that we should not worry about carbon dioxide, since the main greenhouse gas is water vapor. This is partly true, but it is the carbon dioxide that controls the... More

When we discover extra-terrestrial life, how will this information be distributed to the public?

Thanks for asking “when” not “if” we discover extraterrestrial life. If we found either extant or fossil life in meteorites or on the surface of a planet like Mars, there would probably be several months of intense scientific work before an announcement was made. NASA already had this sort of... More

I want to thank you. At 26 I am a mother of 2. The last few weeks I have been loosing sleep over this 2012 doomsday issue that the media promotes to make a dollar, and frankly I think it is sick. I spent the last few hours reading your answers. I hope i can sleep better tonight; I dont want to loose my children to some awful disaster. I hope everyone out there believes NASA and not the conspiracy theory. But as i read your answers I see you get irratated with people for asking the same questions; please try to understand these people are like me waking up at night wondering if they should start trying to figure out how to survive a disaster or if they are being crazy. My only question is if the Earth poles were due to change as well as the sun, can we expect anything at all to happen? or would we notice nothing?

I am sorry if I sometimes get irritated, but so many people who write don’t bother to read any of my previously posted answers, yet they check the box that says “I have used the search feature (blue box to the right) to verify that a question similar to mine... More

On reversal of the Earth's magnetic polarity, you wrote "the magnetic polarity of Earth, which does change irregularly with a magnetic reversal taking place every 400,000 years on average. As far as we know, such a magnetic reversal doesn’t cause any harm to life on Earth. A magnetic reversal is very unlikely to happen in the next few millennia, anyway." If the last shift of the Earth's polarity occured 780,000 years ago, how can you say that it will not occur within the next few millenia, because you are indeed correct in that it does occur an average every 400 millenia. Furthermore I question your statement about the effect such a reversal will have on the life of our planet. While we are not certain about the extent of the effect, most scientists agree that when a reversal event occurs the Earth's magnetic field is all but non-existent, and then severely weakened for some time afterward. The magnetic field surrounding us is our primary shielding from a bombardment of cosmic and solar radiation.

In answer to your first question, the Earth’s polarity reversal is not a periodic phenomenon. While the timing may not be random either, that assumption is consistent with the data. If it is random, and happens on average every 400,000 years, then the probability of it happening in the next... More

What are the theories about life on europa? is it that the ice is melting and therefore there is water so there must be life? and also i have seen drawings of what the europa rover would be like. have they made an actual model?

Europa has an ocean of liquid water larger than the oceans of Earth (with less area but much deeper), covered with a crust of ice at least several kilometers thick. The water is liquid because Europa has an interior heat source caused by stress from Jupiter tides. This is much... More

More reader feedback on the 2012 hoax:

Hi, I work in astronomy education outreach at University of Texas and wanted to thank you for putting together the 2012 Q&A site. We get similar questions all of the time and it really helps to have a site to refer people to. One thing I think you might want... More