Eruptions on the sun's surface can blast tons of plasma into space -- sometimes right at the Earth. Astonishing pictures show the giant flares and clouds of ionized gas erupting from the star.
Earth is bracing for a cosmic tsunami Tuesday night as tons of plasma from a massive solar flare head directly toward the planet.
The Sun's surface erupted early Sunday morning, shooting a wall of ionized atoms directly at Earth, scientists say. It is expected to create a geomagnetic storm and a spectacular light show -- and it could pose a threat to satellites in orbit, as well.
"This eruption is directed right at us and is expected to get here early in the day on Aug. 4," said Leon Golub of the Harvard-Smithsonian Center for Astrophysics. "It's the first major Earth-directed eruption in quite some time."
The solar eruption, called a coronal mass ejection, was spotted by NASA's Solar Dynamics Observatory, which captures high-definition views of the sun at a variety of wavelengths. SDO was launched in February and peers deep into the layers of the sun, investigating the mysteries of its inner workings.
"We got a beautiful view of this eruption," Golub said. "And there might be more beautiful views to come if it triggers aurorae."
Views of aurorae are usually associated with Canada and Alaska, but even skywatchers in the northern U.S. mainland are being told they can look toward the north Tuesday and Wednesday evenings for rippling "curtains" of green and red light.
When a coronal mass ejection reaches Earth, solar particles stream down our planet's magnetic field lines toward the poles. In the process, the particles collide with atoms of nitrogen and oxygen in the Earth's atmosphere, which then glow, creating an effect similar to miniature neon signs.
The interaction of the solar particles with our planet's magnetic field has the potential to create geomagnetic storms, or disturbances, in Earth's magnetosphere. And while aurorae are normally visible only at high latitudes, they can light up the sky even at lower latitudes during a geomagnetic storm.
Fortunately for Earth-bound observers, the atmosphere filters out nearly all of the radiation from the solar blast. The flare shouldn't pose a health hazard, Golub told FoxNews.com.
"It's because of our atmosphere," he explained, "which absorbs the radiation, as well as the magnetic field of the Earth, which deflects any magnetic particles produced."
The radiation "almost never" makes it to ground, he noted, though pilots and passengers in airplanes may experience increased radiation levels akin to getting an X-ray.
The solar particles also could affect satellites, though scientists think that possibility is remote. Orbital Sciences Corp. believe a similar blast may have knocked its Galaxy 15 satellite permanently out of action this year.
This type of solar event has both government officials and satellite manufacturers worrying.
NASA scientists warned recently that high-energy electric pulses from the sun could cripple our electrical grid for years, causing billions in damages. In fact, the House is so concerned that the Energy and Commerce committee voted unanimously to approve a bill allocating $100 million to protect the energy grid from this rare but potentially devastating occurrence.
The sun's activity usually ebbs and flows on a fairly predictable cycle. Typically, a cycle lasts about 11 years, taking roughly 5.5 years to move from a solar minimum, a period of time when there are few sunspots, to peak at the solar maximum, during which sunspot activity is amplified.
The last solar maximum occurred in 2001. The latest minimum was particularly weak and long- lasting.
The most recent solar eruption is one of the first signs that the sun is waking up -- and heading toward another maximum.
Space.com contributed to this report.