Magnetic Field Springing a Leak in Earth's Air Supply

Atmosphere Hunter (2:43 PM) I don't have a definite number from our data, mainly because it's very difficult to estimate.
But two figures are usually given for how much of the Earth's atmosphere has lost due to solar wind interaction: between 18 percent and 2 to 3 percent.
The lower figure would be due to plenty of recycling.

Dave on Earth (2:45 PM) Wow -- so there's quite a bit of uncertainty.

Atmosphere Hunter (2:46 PM) Well, our results indicate that the real value should be closer to 18 percent than 2 percent.
But looking into that is one of our future projects.
As for the uncertainty? Precisely why we want to understand the physical mechanisms (and not just measure the current escape rate).

Dave on Earth (2:47 PM) Even at 18 percent total, that seems like a slow leak when spread out over a few billion years.
Time for my alarmist follow-up questions, though: Can we expect Earth to lose most of its atmosphere soon? If so, when?

Atmosphere Hunter (2:49 PM) I've read that the increasing brightness of the sun will boil off the oceans in about one billion years...
And the content of the oceans is much, much greater than that of the atmosphere.

Dave on Earth (2:51 PM) So the sun might be a bigger threat to us than a tiny "leak" in our air supply?

Atmosphere Hunter (2:51 PM) Yes.

Dave on Earth (2:51 PM) All this talk about losing atmosphere makes me think of Mars. It once had plenty of water and air a long time ago, and a magnetic field.
Now it's a cold, red dust ball. Is Mars' fate our planet's own fate? Or is that a bit of a stretch?

Atmosphere Hunter (2:53 PM) First let's consider some big differences between Mars and Earth.
One: Mars has a much lower mass than Earth, and therefore less gravity. That's the most important difference when you're talking about atmosphere loss.
Mars also lacks an intrinsic magnetic field, but the atmospheric loss is, despite low gravity, not so high.
Then again, the precise number for its rate of atmosphere loss is the subject of considerable debate.

Dave on Earth (2:56 PM) I see. So if you were to sum up your findings about the Earth, my guess is you'd say we don't have really anything to worry about.

Atmosphere Hunter (2:56 PM) No, there is nothing to worry about... at least when it comes to a leaky atmosphere.

Dave on Earth (2:56 PM) As a scientist, what are you worried about?

Atmosphere Hunter (2:57 PM) Overpopulation has to be the main problem we are facing.
In the long run, it is a larger threat than any increased carbon dioxide levels and such.

Dave on Earth (2:58 PM) I might have to agree with you -- after all, making room for more people has lead to clearing the forests, plundering the oceans and all kinds of other trouble.
But it's a politically incorrect subject. People immediately think of genocide, sterilization, child laws and other such inhumane solutions.
What is your take?

Atmosphere Hunter (3:00 PM) Well, there are no easy solutions -- but that is no reason for not trying.
Increased education levels, female empowerment, accepting contraceptives.
Making life better for the poorest, preferably without exhausting all natural resources.
It's quite an understatement to say this is really a challenging task.

Dave on Earth (3:02 PM) We could go on all day chatting about this, so I'll rope us back in.
What do you think is the most amazing thing about our atmosphere?

Atmosphere Hunter (3:02 PM) Its composition!

Dave on Earth (3:03 PM) What's so special about it?

Atmosphere Hunter (3:03 PM) It is so different from all other atmospheres we know of -- because of life.
It's filled with oxygen, which is a very reactive gas and combines with most everything (think of rust).
So plant life must keep refilling and processing it -- and it can do that on a grand scale affecting the entire planet.
Plants once changed the atmosphere on Earth completely -- we can also affect it, and must act responsibly.

Dave on Earth (3:05 PM) Anything else rattling around you need to get out?

Atmosphere Hunter (3:05 PM) I don't think so -- I'd just like to thank you for an interesting experience!

Dave on Earth (3:06 PM) Oh, for sure. Thank you, and have a great evening!

Atmosphere Hunter (3:07 PM) And have a nice afternoon. Bye!

Article posted September 10, 2008.

Got something to say? E-mail your questions, comments or concerns to discoveryspace@discovery.com. Your words may appear on Discovery Space.

MORE SPACE INTERVIEWS