Answered Questions

There is a lot of support in the scientific community for the theory that the moon was created by a collision of a body (named Theia) with the proto-Earth. What would you say the odds are that some portion of the building blocks of life on Earth were actually formed on Theia as opposed to being formed on Earth?

I would rate this as unlikely for two reasons. First, the Moon-forming collision happened very early, within the first few million years of solar system history, before either the proto-Earth or the impactor had a chance to cool down. Second, the collision itself was so violent that most chemical bonds were broken and most...

August 19, 2008 More

The primitive Earth collided with a Mars sized protoplanet and created the moon, Venus had a similar collision which drastically slowed its rotation and now it seems that Mars had a major collision which reshaped one of its poles. This would suggest that as a planetary systems form, two(or possibly more) planets can coaless in each orbital slot. Do you think it is possible that on rare occasions, the size and velocity of the dual planets might match, to leave a stable system of identical planets in the same orbit, but on opposite sides of the star?

The situation you describe, with nearly identical planets in the same orbit but on opposite sides of the the star, is dynamically unstable. So no, this configuration is not possible. In addition, of course, we could easily detect such a "counter-Earth" if it existed, since even if it remained hidden behind the Sun, this...

August 18, 2008 More

I would like to ask you that if anyhow we manage to send some bacterias and viruses to certain planets like mars, then is there any possible hope of their growth and development? since bacterias are the one who can live under extreme condition and can survive anyhow.

No known terrestrial species can grow under current martian surface conditions. Although there are many extremophiles that can tolerate a wide range of environments on Earth, these do not include conditions as dry and cold and exposed to UV radiation as we find on the surface of Mars. Of course, we have already transported...

August 15, 2008 More

I smile every time I see reference to the Mayan calendar and the end of the world in 2012. On my wall is a calendar that ends on December 31 2008. I feel fairly confident that the world won't end then. As in years past, I will simply go out before then and buy one that starts on January 1 the following year and finishes on December 31 that same year. So I guess the Mayan calendar will just roll over to the start and carry on as before.

You are absolutely correct -- and this is a good analogy. Calendars are for keeping track of time, not predicting the future.
David Morrison
NAI Senior Scientist

the planet system known as pleiades..have we the technology too view this planetry system as i have read alot on the internet about aliens visiting earth from there.? here is one of the more facinating sites relating too this http://www.galactic-server.com/rune/stewens.html. As for Area 51 there has been leaked information from ex employees stating there is in fact been aliens taking there and experimented on..? and like you say we have no knowledge of what really goes on in that facilty too say otherwise.. As for us humans scientist's say we originated from microbes and evolved over millions of years then what can we say about the bible adam and eve?

I am afraid that you have been reading fiction on the Internet and mistaking it for facts. There is no planet system called the Pleiades, and the website you reference is pretty silly, including the obviously fake photo of a "flying saucer". I have answered questions about Area 51 before, noting that it was...

August 13, 2008 More

How should teachers approach the subject of Pluto? Our science books (published about 4 years ago), teach that Pluto is a planet. However, it is my understanding that it has been demoted to a dwarf planet. I always do a solar system project each year, Should we continue to include Pluto? I want to make sure my students are learning the correct information. Thanks!

Over history, the word planet has had a variety of meanings, reflecting our growing understanding of the solar system. Before Copernicus, the term was used for any celestial "wanderers" that moved against the background of "fixed" stars. There were 7 wanderers: Sun, Moon, Mercury, Venus, Mars, Jupiter and Saturn. The...

August 12, 2008 More

I know about asteroid Apophis coming back in 2036, heres a few questions about it: 1. What is the probability that it will pass through the keyhole in 2029? 2. What is the probability that it will impact Earth in 2036. 3. If Apophis (hopefully) misses us in 2036, wouldn't it swing back around in the years to come and hit us? 4. Is there any possible way to nudge it off its collision course?

New observations over the past several years have greatly improved our knowledge of the orbit of Apophis. The slight remaining impact risk is associated with whether Apophis, in its close flyby of Earth on 13 April 2029, will pass through a dynamical "keyhole" less than 1 km across, which would result in an impact...

August 11, 2008 More

Hi ,My question is more of curiosity & that is are we genetic inbreeds,the reason i ask this ridiculous question is because i struggle with the two concepts that is creation by god & evolution,know my reason for suggesting the word in breed is if god banished adam & eve & eve bore kane & able who did kane breed with ?

Modern humans first appeared on Earth, in Africa, a couple of hundred thousand years ago. In addition, there is increasing evidence of an event somewhat less than one hundred thousand years ago that severely reduced the human population, creating a sort of genetic bottleneck, with perhaps only a few thousand survivors. One plausible suggestion...

August 8, 2008 More

(17 years old) Do you being a "Astrobiologist" actually believe in life in other places of the universe? Ive asked that question to some other people and they reply simply "No"... Ok well then i say did you know the probabillity for us being the only "life" in the universe is 0.000000000000000000001... To our knowledge, at least the common citizen their is no such thing but i thought to my self after finding this wonderful site, i wonder what a Astrobiologist thinks!?

This seems like a simple question, but it is complicated by the phrase "believe in". Beliefs are opinions we hold without supporting evidence. There is no evidence yet concerning life on any world beyond Earth. But of course, I and other astrobiologists expect that there is abundant life in the universe. We would not...

August 7, 2008 More

What is the fact about Aliens or UFOs are visiting our Earth for last 60 years? Is NASA in contact with Aliens ?

This question is answered on the Ask an Astrobiologist webpage under 'Frequently Asked Questions'. No, NASA is not in contact with aliens, and I have seen no evidence that aliens are visiting Earth either.
David Morrison
NAI Senior Scientist