When storms in outer space occur near Earth, it’s called space weather. Rather than the more commonly known weather within our atmosphere — rain, snow, wind, etc. — space weather comes in the form of solar flares and geomagnetic storms caused by disturbances emanating from the sun. The following are five far-out facts about space weather.
Gases and particles stream from the sun to Earth at speeds of a million mph. This stream is called the solar wind. Even though the sun is 93 million miles (150 million kilometers) from Earth, the solar wind can affect Earth and the rest of the solar system.
Strong solar storms can cause fluctuations of electrical currents in space, energizing electrons and protons trapped in Earth’s varying magnetic field. These disturbances can disrupt radio communications, GPS, power grids and satellites.
Imagine all the ways in which people are dependent upon satellites: space travel, cell phones, weather prediction, TV, search and rescue, navigation, military surveillance, credit card and ATM transactions, and more. As people become more dependent on technology, the need for space weather monitoring and forecasting becomes more important.
A real drag
High-energy particles and radiation from the sun can heat Earth’s atmosphere as they collide with common molecules, like nitrogen and oxygen. The heated air rises and causes the upper atmosphere to expand like a balloon. If an electromagnetic storm is strong enough, the atmosphere can expand so much that it engulfs the orbits of low-Earth-orbit satellites, slowing them down and decreasing their altitude. This process is called orbital drag.
During an extreme magnetic storm event, a satellite could drop nearly a third of a mile in elevation in one day, according to a paper published in the November issue of Space Weather.
“That’s a lot. In fact, it’s as much as a satellite would typically lose in a year,” Denny Oliveira, the paper’s author, said. Oliveira is a scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
Ground control to Major Tom
Space weather can have serious medical effects on the brave astronauts who explore and work in space.
During geomagnetic storms, the chance that astronauts will be hit by damaging particles increases. This can alter their DNA and may lead to cancer. That’s why the International Space Station has increased shielding around crew quarters, and why NASA carefully monitors each astronaut’s radiation exposure throughout his or her career.
The Van Allen Probes will help develop better predictive models so that astronauts will have increased warning of storms.
Those gorgeous lights
Some storms have silver linings. In the case of space weather, that lining is the aurora, commonly known as the Northern or Southern Lights. When electrons and protons around Earth are energized by solar disturbances, they can follow Earth’s magnetic field toward the North and South magnetic poles, where they collide with atmospheric molecules. This energizes them and causes them to glow. The colors that result depend on the types of nearby atmospheric gases but are most commonly a brilliant yellow-green.
Looking to the future
NOAA’s Space Weather Prediction Center (SWPC) is the official source for space weather forecasts. It predicts solar storms, much like the National Weather Service predicts weather here on Earth.
To predict these storms, forecasters watch the sun for solar flares and coronal mass ejections (CMEs). Solar flares are massive explosions on the sun’s surface and often happen near sunspots. They send tons of energy whizzing through space at the speed of light. The biggest solar storms arise from CMEs, and the velocity of a CME can exceed 5 million mph.
To learn about the intersection of supply chains and space technology, join the FreightWaves SpaceWaves virtual event on Thursday.