Will we ever leave Earth?

Originally posted by bigduff
its looking like the end o well

The idea that a planetary magnetic field is a requirement for life may be true but without such a protective field, the normal route we think ends up with life, that is to say, the mixing of molecules to produce ever more complex ones will have a big break put on them by the intense ultraviolet light coming from stars like our sun in a planet's early history.

It would at the very least cause a huge slow down in how such molecules proceed on the journey to life.

The UV will break apart molecular combinations as soon as they form. That is a direct consequence of the lack of a magnetic field.

So reactions that proceed to life forms would have to be hidden from such UV like buried layers of clay and such.

So the lack of magnetic fields on a planet would at the very least kill off possibilities of life forming directly on the surface.

Originally posted by sonhouse
The UV will break apart molecular combinations as soon as they form.

I don't know where you get that from. Asteroids often contain plenty of biologically important molecules.
Also, life may have started in the deep oceans were UV light would not have been a problem.
The biggest problem with UV today is that it causes a particular reaction in DNA (the creation of dimers). If UV had been more prevalent during the evolution of life, then it would probably have used different bases for DNA that do not suffer from that problem.
As it is, the cells repair machinery is able to repair most of the damage caused by UV radiation - otherwise you would be dead from skin cancer in a week.

Originally posted by twhitehead
I don't know where you get that from. Asteroids often contain plenty of biologically important molecules.
Also, life may have started in the deep oceans were UV light would not have been a problem.
The biggest problem with UV today is that it causes a particular reaction in DNA (the creation of dimers). If UV had been more prevalent during the evolution ...[text shortened]... t of the damage caused by UV radiation - otherwise you would be dead from skin cancer in a week.

well sure, it repairs now. I was talking about prebiotic molecules that would be blasted apart with an intense burst of UV. I also said that UV would not stop those molecules from evolving if hidden from that UV. UV is ionizing radiation.