Alien Viruses

[David P. Frazier]

In article <46p6ij$kg8 at newsbf02.news.aol.com>, kardo6 at aol.com (Kardo6) wrote:

>   
>   I have heard that viruses can live for thousands of years without dying
> because when not attacking living cells, they do not metabolize. If this
> is true is it concievable that viruses could survive the vacuum and vast
> distances of space and travel between planets, could some of the viruses
> of earth in fact be aliens.

I may regret becoming involved in this post, but I believe the inquiry was 
earnest.  In fact, no, the viruses on Earth are not even remotely likely to 
be of alien origin.  While it is true that viruses might survive in extreme
cold or in a vacuum, the heat involved in reentry of any material to which
a particle might be attached would certainly destroy that particle. 
In addition, high levels of ionizing radiation, such as those found in 
space, are known to destroy nucleic acids and ultraviolet radiation destroys
both nucleic acid and protein.  Finally, there is the problem of how viruses
might be launched into space in the first place.  The combination of all
of these reasons is why others who responded to this post failed to take it
seriously.  It is simply impossible.

David P. Frazier Ph.D.
Department of Microbiology and Molecular Genetics
Harvard Medical School