New NASA Views of Storms in SpacePresented by Dr. Eric Christian

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January 19, 2011

New NASA Views of Storms In SpaceThe Sun as a StarMagnetism and the SunSolar ActivityStorms in Space (Space Weather)Solar Science Now and in the Future

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The Sun as a Star

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Our Sun is a very ordinary star

Figure shows relative sizes and colors of some nearby stars.

Vega: 25 light years (ly)U. Andromedae: 44 lyGamma Cephei: 45 lySun: 93 million milesEpsilon Eridani: 10.5 lyGliese 581: 20 ly

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Hertzsprung-Russell Diagram

Hotter

Stars spend most of their life on the Main Sequence.

On the main sequence, bigger stars are brighter and hotter.

There are fewer big stars, many more small stars.

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Poll Question:

Billions of years from now, the Sun will end up as:

A: A SupernovaB: A Black HoleC: A Red GiantD: A White DwarfE: A Neutron Star

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Why ordinary is goodLarge, bright stars don’t last very long.

Smaller stars are more stable.

Largest stars only stay on the main sequence for a few million years, the smallest can last a trillion.

Our Sun will be main sequence for about 10 billion years.

But smaller stars have a smaller “zone of habitability”, where planets can have liquid water. Therefore a smaller chance of worlds with life.

In the middle has long life and large zone of habitability.

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Life Cycles of Stars

The NASA websites “Starchild” and “Imagine the Universe” have posters and activities on the Life Cycles of Stars for elementary and high school respectively.

http://imagine.gsfc.nasa.gov/docs/teachers/lifecycles/stars.html

The Sun as a Star

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Any Questions?

Plasma, Magnetism and The Sun

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Four Ordinary States of Matter

Solid: Keeps the same shapeLiquid: Fills up the bottom of the container, but keeps the same volumeGas: Fills up the container it’s inPlasma: An electrically-charged gas

Most of the Universe is PLASMA!

Including the Sun and all stars

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Two types of Magnets

Permanent Magnet: Iron, Nickel, and a few other elements that, when they solidify in a magnetic field or are otherwise magnetized, remain magnetized and generate their own magnetic field.

Electromagnet: Moving charged particles generate a magnetic field. In a coil of wire, each loop combines to make a stronger magnetic field.

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Think about Magnetic Objects in the Solar System:

Is the Sun a permanent magnet or an electromagnet?

How about the Earth?

How about Mars?

[Type your responses in the chat]

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The Sun is a magnetic star

The Sun is an electromagnet. Moving plasma causes electric currents in the Sun, which generate a magnetic field.

The Earth is also an electromagnet with the magnetic field generated by currents at the molten core-mantle boundary.

Mars has small, irregular magnetism (a permanent magnet).

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You can see the magnetic fieldof the Sun

Image from TRACE satellite of magnetic loops on the Sun

Plasma, Magnetism and The Sun

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Any Questions?

Solar Activity

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Magnetism is the cause of solar variability

Differential rotation (the Sun’s equator spins faster than the poles) “winds up” the solar magnetic field

Figures from TRACE website: trace.lmsal.com

I like to think of the Sun’s magnetic field as a ball of rubber bands.

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11 year (approximately) solar cycle

The Sun’s magnetic field flips polarity every 11 yearsThis is the major factor in the Sun’s variability.

11 year of solar images in X-rays (left) and magnetic field (right)

When the field flips, there are more sunspots and more solar activity. This part of the solar cycle is called Solar Maximum.

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11 year (approximately) solar cycle

11-year solar cycle is not constant in either duration or intensity.

Sunspots are an effect of solar activity and don’t exactly measure solar activity.

The number of sunspots is the longest running direct observation of solar activity.

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Chat: What is the Sun’s effect onGlobal Warming

There has been a lot of political hype about Global Warming, with some people claiming that all the recent warmth is due to changes in the Sun, and others saying that it’s all man-made.

What does the science say?

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Sunspots

Very bright, just look dark compared to rest of the Sun

Close up of Sunspot showing magnetic field strength (left) and visible light (right)

From HinodeSpacecraft(Japanese/US Mission)

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Sunspots

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Prominences and filaments

Prominences are bright loops off the edge of the Sun.

Filaments are dark ribbons on the face of the Sun.

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Prominences and filaments . . .

Are the same thing!Image from Solar Dynamics Observer

Solar Activity

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Any Questions?

Storms in Space(Space Weather)

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Coronal Mass Ejections (CMEs)

Big bubbles of plasma, particles and magnetic field, that break away from the Sun.

The hurricanes of space weather. CMEs can have effects all the way out to the edge of the solar system. Dangerous to Astronauts, satellites, and even to equipment down on Earth

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Solar Flares

Magnetic Field suddenly snaps.Particles are accelerated to almost the speed of light.

Dangerous to Astronauts and satellites.

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The Atmosphere of the Sun

The solar wind has blown a bubble in space that extends all the way beyond Pluto!

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Most recognized effect of Space Weather:Auroras

Interaction of the Sun’s magnetic field and the Earth’s magnetic field.

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Aurora from Space

Skylab

Other planets

Earth aurora from space.

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Space Weather is Important

Storms in Space(Space Weather)

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Any Questions?

Solar Science Now …And in the Future!

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STEREO (Solar Terrestrial Relations Observatory)

stereo.gsfc.nasa.govFebruary 6th. The 360 degree Sun.

STEREO Orbits

Our first 3D images of the Sun

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Solar Dynamics Observatory (SDO)

The High-Definition Television of Solar Astronomy

Launched February, 2010

sdo.gsfc.nasa.gov

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NASA’s network of Space Weather Satellites

A fleet of spacecraft spread throughout the solar system.

Includes both weather stations (local conditions) and weather satellites (image large areas)

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Solar Probe PlusWill be launched in 2018

Our first mission to a star. Closest approach is only about 4 million miles from the Sun. The Earth is 93 million miles away and the Sun is 400,000 miles in radius.

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Sun Earth Daysunearthday.nasa.gov

A yearly event for NASA Education and Public Outreach. Every year there is a different topic, and website includes lesson plans and activities, podcasts, and much more. Join us this year for

“Ancient Mysteries, Future Discoveries”

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Sun Earth Day

Space Weather Viewerhttp://sunearthday.gsfc.nasa.gov/spaceweather/

Pointers to lesson planshttp://sunearthday.nasa.gov/2011/getinvolved/

Solar Science Now …And in the Future!

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Any Questions?

Thank you to the sponsor of tonight's Web Seminar:

http://learningcenter.nsta.org

http://www.elluminate.com

National Science Teachers AssociationDr. Francis Q. Eberle, Executive Director

Zipporah Miller, Associate Executive Director Conferences and Programs

Al Byers, Assistant Executive Director e-Learning

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