The Sun-Earth Connection: Heliophysics Solar Storm and Space Weather - Frequently Asked Questions

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Science Mission Directorate

Graphic representing the various Heliophysics disciplines; Sun, Earth, Space Weather, Near-Earth Space and the Magnetosphere. Understanding the Sun, Heliosphere, and Planetary Environments as a single connected system is a goal of the Heliophysics Research Program.
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Solar Storm and Space Weather - Frequently Asked Questions

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  • What is solar activity?

  • What is a solar flare?

NASA Goddard heliophysics scientists answer some common questions about the sun, space weather, and how they affect the Earth. This is part one of a two-part series.
It addresses: 1. What is space weather? 2. What are coronal mass ejections? 3. What are solar flares? 4. What are solar energetic particles? 5. What causes flares and CMEs? Credit: NASA/Goddard

  1. What is a solar prominence?

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    A solar eruptive prominence as seen in extreme UV light on March 30, 2010 with Earth superimposed for a sense of scale. Credit: NASA/SDO
    A solar prominence (also known as a filament when viewed against the solar disk) is a large, bright feature extending outward from the Sun's surface. Prominences are anchored to the Sun's surface in the photosphere, and extend outwards into the Sun's hot outer atmosphere, called the corona. A prominence forms over timescales of about a day, and stable prominences may persist in the corona for several months, looping hundreds of thousands of miles into space. Scientists are still researching how and why prominences are formed.

    The red-glowing looped material is plasma, a hot gas comprised of electrically charged hydrogen and helium. The prominence plasma flows along a tangled and twisted structure of magnetic fields generated by the sun’s internal dynamo. An erupting prominence occurs when such a structure becomes unstable and bursts outward, releasing the plasma.
  2. What is a coronal mass ejection or CME?

  3. Does ALL solar activity impact Earth? Why or why not?

  4. What are coronal holes?

  5. What is a geomagnetic storm?

  6. What is a sunspot?

  7. What is the solar cycle?

  8. What is solar maximum and solar minimum?

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    Eleven years in the life of the Sun, spanning most of solar cycle 23, as it progressed from solar minimum to maximum conditions and back to minimum (upper right) again, seen as a collage of ten full-disk images of the lower corona. Of note is the prevalence of activity and the relatively few years when our Sun might be described as “quiet.” Credit: SOHO EIT, ESA/NASA
    Solar minimum refers to a period of several Earth years when the number of sunspots is lowest; solar maximum occurs in the years when sunspots are most numerous. During solar maximum, activity on the Sun and the effects of space weather on our terrestrial environment are high. At solar minimum, the sun may go many days with no sunspots visible. At maximum, there may be several hundred sunspots on any day.

  9. What is space weather?

  10. Does the Sun cause space weather?

  11. Do space weather effects / solar storms affect Earth?

  12. What are some real-world examples of space weather impacts?

  13. Do scientists expect a huge solar storm in 2013?

  14. How long do space weather events usually last?

  15. How are space weather events observed?

NASA Goddard heliophysics scientists answer some common questions about the sun, space weather, and how they affect the Earth. This is part two of a two-part series.
It addresses: 1. Do all flares and CMEs affect the Earth? 2. What happens when a flare or CME hits the Earth? 3. How quickly can we feel the effects of space weather? 4. Why are there more flares and CMEs happening now? Credit: NASA/Goddard

  1. What are our current capabilities to predict space weather?

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    The Heliophysics System Observatory (HSO) showing current operating missions, missions in development, and missions under study. Credit: NASA
    NASA operates a system observatory of Heliophysics missions, utilizing the entire fleet of solar, heliospheric, and geospace spacecraft to discover the processes at work throughout the space environment. In addition to its science program, NASA’s Heliophysics Division routinely partners with other agencies to fulfill the space weather research or operational objectives of the nation.

    Presently, this is accomplished with the existing fleet of NOAA satellites and some NASA scientific satellites. Space weather “beacons” on NASA spacecraft provide real-time science data to space weather forecasters. Examples include ACE measurements of interplanetary conditions from the Lagrangian point L1 where objects are never shadowed by the Earth or the Moon; CME alerts from SOHO; STEREO beacon images of the far side of the Sun; and super high-resolution images from SDO. NASA will continue to cooperate with other agencies to enable new knowledge in this area and to measure conditions in space critical to both operational and scientific research.

    To facilitate and enable this cooperation, NASA’s makes its Heliophysics research data sets and models continuously available to industry, academia, and other civil and military space weather interests via existing Internet sites. These include the Combined Community Modeling Center (CCMC) and the Integrated Space Weather Analysis System (ISWA) associated with GSFC. Also provided are publicly available sites for citizen science and space situational awareness through various cell phone and e-tablet applications.

    Beyond NASA, interagency coordination in space weather activities has been formalized through the Committee on Space Weather, which is hosted by the Office of the Federal Coordinator for Meteorology. This multiagency organization is co-chaired by representatives from NASA, NOAA, DoD, and NSF and functions as a steering group responsible for tracking the progress of the National Space Weather Program.
  2. How long have we known about space weather?

  3. Have scientists seen changes in the intensity of space weather?

  4. How strong is solar wind (compared to wind on Earth)?

  5. What are the northern and southern lights and are they related to space weather?

  6. Who is responsible for predicting space weather and sending alerts when there is solar activity?

  7. How do you forecast space weather?

  8. Why is forecasting space weather important?

  9. When do the effects of space weather show up?

  10. Where can I get more information?

  11. Sun facts:

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    The image gives a basic overview of the Sun’s parts. The cut-out shows the three major interior zones: the core (where energy is generated by nuclear reactions), the radiative zone (where energy travels outward by radiation through about 70% of the Sun), and the convection zone (where convection currents circulate the Sun’s energy to the surface). The surface features (flare, sunspots and photosphere, chromosphere, and the prominence) are all clipped from actual SOHO images of the Sun. Credit: NASA/SOHO
    The Sun is a magnetic variable star at the center of our solar system that drives the space environment of the planets, including the Earth. The distance of the Sun from the Earth is approximately 93 million miles. At this distance, light travels from the Sun to Earth in about 8 minutes and 19 seconds. The Sun has a diameter of about 865,000 miles, about 109 times that of Earth. Its mass, about 330,000 times that of Earth, accounts for about 99.86% of the total mass of the Solar System. About three quarters of the Sun's mass consists of hydrogen, while the rest is mostly helium. Less than 2% consists of heavier elements, including oxygen, carbon, neon, iron, and others. The Sun is neither a solid nor a gas but is actually plasma. This plasma is tenuous and gaseous near the surface, but gets denser down towards the Sun's fusion core.

    The Sun, as shown by the illustration at right, can be divided into six layers. From the center out, the layers of the Sun are as follows: the solar interior composed of the core (which occupies the innermost quarter or so of the Sun's radius), the radiative zone, and the convective zone, then there is the visible surface known as the photosphere, the chromosphere, and finally the outermost layer, the corona. 
The energy produced through fusion in the Sun's core powers the Sun and produces all of the heat and light that we receive here on Earth.

    The Sun, like most stars, is a main sequence star, and thus generates its energy by nuclear fusion of hydrogen nuclei into helium. In its core, the Sun fuses 430–600 million tons of hydrogen each second. The Sun's hot corona continuously expands in space creating the solar wind, a stream of charged particles that extends to the heliopause at roughly 100 astronomical units. The bubble in the interstellar medium formed by the solar wind, the heliosphere, is the largest continuous structure in the Solar System.

    Stars like our Sun shine for nine to ten billion years. The Sun is about 4.5 billion years old, judging by the age of moon rocks. Based on this information, current astrophysical theory predicts that the Sun will become a red giant in about five billion (5,000,000,000) years.
  12. Why didn't the world end in 2012?

    For an answer to this and other 2012 questions, please visit the NASA 2012 FAQ page at http://www.nasa.gov/topics/earth/features/2012.html.

Should we be concerned about solar storms in 2012? Heliophysicist Alex Young from NASA Goddard Space Flight Center sorts out truth from fiction. Credit: NASA/Goddard

Jennifer Rumburg
NASA Headquarters

Page Last Updated: September 30th, 2013
Page Editor: Holly Zell