|
|
 |
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 thousand... Click here for more.
|
|
|
|
Does SETI look for light pulses as well as radio signals from the stars? Is there any other group that searches for any signals from space besides SETI? |
| |
SETI means the search for extraterrestrial intelligence, so by definition any such search, looking for radio signals or light pulses, is a part of SETI. There are quite a few SETI groups around the world. One of the oldest and largest is at the SETI Institute in Mountain View, California [http://www... Click here for 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 has not already been answered.”. I would ... Click here for more.
|
|
|
|
WHY, do you and some others say that there shall be no alignment of Earth, the Sun, and the center of the universe, when there are other scientist that say there shall be? |
| |
The people who say there will be alignment of Earth, the Sun, and the center of the universe are not scientists. They are hoaxers.
David Morrison
NAI Senior Scientist
|
|
|
|
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 struct... Click here for 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 experi... Click here for 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 necessarily tha... Click here for more.
|
|
|
|
Don Yeomans from NASA, July 2008 writes an article "Why Study Comets" saying: "It is not a question of whether a comet will strike the Earth, it is a question of when the next one will hit." At what interval do you believe a "comet hitting Earth" event will occur? being the last one took place 65 million years ago?! |
| |
First, we don’t know when the next comet hit will take place. The astronomical evidence is that there are few if any comets smaller than about 2 km diameter, and in the size range of a few kilometers, comets represent only about 1 percent of the impact risk, with the asteroids making up 99 percent. ... Click here for more.
|
|
|
|
I am a 28-year veteran English teacher and I would like permission to print a copy of your page of 20 questions about the 2012 doomsday scare for distribution to my colleagues. While reading on another site about some of the letters you received from teenagers, it occurred to me that we teachers have an obligation to be informed on this issue in order to address fears that our students may have. The topic could also be used for study units on propaganda techniques and/or manipulation of language, critical thinking skills, free-speech issues, media studies, the importance of thorough research, and on and on. Mostly, though, we might save a life, or, at the very least, calm someone down. The whole 2012 thing for me has gone from mild amusement to disgust to real alarm over our nation's ignorance. The doomsday scare has potential to do real harm, and reading of the kids who wrote to you considering suicide woke me back up to one of the important things we have to deal with besides our curricula, and that is the mental, emotional, and physical well-being of our students. |
| |
Thank you for your note. You are very welcome to use the 20 questions and any other information from this website. I especially recommend this 4-minute video for the students who are more comfortable getting their information from Youtube than written texts. Good luck!
For video: Click here for more.
|
|
|
|
I have always wondered if it is possible that there could be a planet in a synchronis orbit with earth but on the opposite side of the sun from us. We can't see the other side of the sun and our long range probes are looking away into deep space as they leave our solar system. |
| |
No, there cannot be a “counter-Earth” — any such planet would be immediately detected by its gravitational effects on the orbits of other planets.
David Morrison
NAI Senior Scientist
|
|
|
Stay Updated with RSS Feeds