The Science of Sustainability

Living in the Sun's Atmosphere

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Illustration of a blast of solar wind impacting
Earth's protective magnetic field. Credit: NASA
Breathe in, exhale. Feel the air in your mouth, windpipe, and lungs. That's a sample of Earth's atmosphere: the thin layer of gases enveloping our planet.

Did you know that the Sun also has an atmosphere, and that the Earth is inside it? In fact, the Sun's envelope of gases extends well beyond the orbit of Pluto, out to the regions of the solar system where the 3-decade-old Voyager spacecraft are only now reaching.

"Space weather" refers to the conditions in space caused by the outflow of electrically charged gases (plasma) coming from the Sun—what we call the "solar wind." The term "space weather" may conjure images of cosmic tornadoes, astral lightning bursts, and some Star Trek version of a galactic hurricane– but actual space weather is nothing so Earthly and familiar.

First of all, the "air" in space is nothing like the atmosphere we draw our breath from. Earth air, at the surface, is made of nitrogen, oxygen, argon, carbon dioxide, water vapor, and other trace elements, and is relatively dense. "Space air" is mostly hydrogen– ionized hydrogen at that (meaning stripped of its electrons and so electrically charged; the separated electrons are also blowing along in the solar wind).

Second, the gases of the solar wind are extremely rarified. Despite the talk of a solar atmosphere, solar wind, and space weather, space within the solar system is still almost a complete vacuum. At Earth's distance from the Sun, the average density of the solar wind is somewhere between 6 and 9 atoms (mostly hydrogen) per cubic centimeter. If you spread out the gas contained in an ordinary party balloon to this same thinness, it would fill a volume of space over 10 miles across!

Third, the solar wind, for all its sparseness, blows fast! Depending on conditions of space weather, the flow of solar wind past the Earth can speed along anywhere from 200 to 900 kilometers per second! Earth's fastest winds slug along at only a few hundred kilometers per HOUR.

So how does space weather—the changing conditions of the solar wind—affect us on Earth? How might you, personally, have experienced, directly or indirectly, the effects of the Sun's gentle breeze?

The most familiar phenomenon caused by space weather is Earth's beautiful auroras —the northern and southern lights. Interactions between the solar wind and Earth's magnetic field and electrically charged particles trapped in it excite atoms in the upper atmosphere to emit light. And it's not just a softly glowing night light: the most powerful auroras can generate up to a trillion Watts of power!

Solar wind "storms" can not only produce more active auroras, but can cause fluctuations in Earth's magnetic field whose effects can be felt on the ground. These "geomagnetic storms" usually pass unnoticed, perhaps causing a tiny change in the direction that compass needles point– but have also been known to overload electrical power grids and cause blackouts.

In the space around Earth, solar storms have been known to damage or disable satellites, and can put unprotected astronauts at risk. Space walks on the International Space Station are scheduled for times when space weather is – so to speak -"sunny and calm."

Thinking about space weather on Earth might seem like worrying over Atlantic hurricanes here in the Bay Area—but with more and more human activity taking place beyond the confines of our atmosphere, this is a very real and vital concern, and is taken very seriously.

Benjamin Burress is a staff astronomer at The Chabot Space & Science Center in Oakland, CA.

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Category: Astronomy, Partners, Physics

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Ben Burress

About the Author ()

Benjamin Burress has been a staff astronomer at Chabot Space & Science Center since July 1999. He graduated from Sonoma State University in 1985 with a bachelor’s degree in physics (and minor in astronomy), after which he signed on for a two-year stint in the Peace Corps, where he taught physics and mathematics in the African nation of Cameroon. From 1989-96 he served on the crew of NASA’s Kuiper Airborne Observatory at Ames Research Center in Mountain View, CA. From 1996-99, he was Head Observer at the Naval Prototype Optical Interferometer program at Lowell Observatory in Flagstaff, AZ. Read his previous contributions to QUEST, a project dedicated to exploring the Science of Sustainability.
  • http://kqed.org hanna

    I am doing a science project and this really helped.

  • Denise Torrisi-Nuno

    Hello Ben,

    I am at a QUEST workshop learning about BLOGS. I have taken a few of your courses at Chabot. I just wanted to drop you a line to let you know that I will be using your blogs as a resourse in my classroom.

  • Commander Scorch

    Wow! I did not know that auroras were caused by the solar wind. It's amazing that they generate more than trillion watts of power. This article was interesting and I learned a lot of space facts. Looking at the picture, I realized how tiny Earth is compared to the Sun. I wonder how Earth's magnetic field has endure the constant blast of the sun's solar wind for millions and millions of years:)

  • InKa WuZ hErE

    I wonder…does anyone know for sure how far out the sun's atmosphere reaches? This stuff is really genuine. Before, I wasn't really into astronomy, but maybe that'll change now that I've read this article. I can't believe that geomagnetic storms can cause black outs!! I never even knew that there was such a thing as geomagnetic storms before I read this article. Also…since the auroras create so much energy, is it poosible to capture that energy and convert it into usable energy??

  • itzLydiaX3

    I have a question…the article says that the Sun has an atmosphere, and space is endless, right? So how far out, exactly, does the atmosphere actually reach? I guess there is no real answer, since we probably haven't researched that far out into space..oh well. And dang, the solar winds do blow fast! I wonder what a spaceship would become if it gets caught in one of those winds. It might get turned into a pretzel, hah! Ooh, I a little curious here..if the solar wind "storms" can change the direction of the compass needle, then does the North pole itself change, or is the compass wrong then, and the North pole is still in the same location? (I wonder how many more questions will come up…) And wow, I didn't know that geomagnetic storms even existed until I read this article. It's pretty interesting, finding about all the waves and the powers of the Sun.

  • KeLLie DuB

    Woah i thought auroara was a color, im sad i was wrong but its nice to learn new things. i think its interesting that all the wind and activity invovled in the sun acts like a vacuum Its crazy how small the earth is camparing to the sun, thinkiing how things that r large to us like sky scrapers would just be microspects on the sun. Its a bummer how ugly the sun in a star marner, arent they supposed to be pretty?
    tt4n

  • ilma1h

    Wow. Space weather really has a big effect on earth. I never really new much about space weather until I read this article. It actually knid of freaks me out, how dangerous the solar storms can be in the space around earth. Reading stuff like this about space also makes me feel claustrophobic. I start thinking about how you can't breathe and all.

  • YD

    Wow! I knew some of things already from this article but not ll of it. I had no idea that the sun had its own atmosphere. Solar winds blow REALLY fast. I think it's amazing how so much of our lives are affected by space and solar winds and stuff. Like how blackouts are caused by solar storms. I have always wanted to see and aurora.

  • SC

    I didn't know that we had that many gases mixed into our atmosphere!! I thought it was a good article because I didn't know that there was weather out in space. Now I know why auroras/the Northern Lights happen. Ok, at the end, it says something about hurricanes. Does that mean it seems like the winds are about the same as a hurricane's?

  • http://www.kqed.org/quest Jessica – a QUEST staffer

    Thanks to all the students that have left interesting comments on this blog post! Just a note about those comments that did not get published – in order to protect privacy, we were not able to publish comments that include detailed information about you or your school (i.e. your full name) nor did we publish comments that did not meet our criteria for contributing to the high-quality conversations held on the QUEST blog.

    The comments we chose to publish are great examples of thoughtful reflections and questions that other visitors to the QUEST blog will be interested in reading.

    Keep the helpful comments coming!

  • http://edublogs.com melissa1h

    The article was really interesting and contained alot of little facts, and statistics I had not known. I did not know what solar storms were before I didn't even know they exsisted, also the part on just how fast these solar winds are going were truly fascinating. It was really great the way that all those little facts were thrown in (the three decade Voyager) especially the auroras in the North Sky, I thought it was just Light and ice reflections. The way that the whole article was truly worded and connected to make sense was a key factor I really enjoyed, and I really did not find anything that was wrong with it, so I liked it, and found the facts easy to understand.

  • Hira

    This article was really interesting. I learned alot of new things. Wow! I didnt know that the sun also has its own atmosphere and the envelope of gasses are huge. There's alot that I need to learn about space.

  • TeaKitty

    I learned so much from this!