Adam wrote:
Hi,

If our magnetic field protects our atmosphere from being blown away
by
solar winds then how come venus can maintain an atmosphere 90x the
pressure of ours without a magnetic field?

Good question.

I thought gravity except Venus is less dense and smaller than Earth
so
I guess thats ruled out.

As you know, magnetic field is not the only thing that helps Earth hang
on to its atmosphere. There is much talk of this as of late because it
appears Mars once had an atmosphere thick enough to allow for liquid
water on its surface.

Can someone help? or point me in the right direction?

As stated above, Venus has a really thick atmoshpere, in other words,
there's an awful lot of atmosphere to ablate. It is also mostly CO2, a
heavy gas thats hard to get rid of. Its gravity is ~.86 that of Earth's
gravity, and more than twice that of Mars.

Stuart