Astronomers have made an exciting planet discovery. Picture our solar system. In the center, there's our star, the sun. Orbiting the sun are eight planets, including Earth. But what about planets outside of our solar system?

About 15 years ago, scientists developed the tools to detect these "exoplanets."

Since then, they have spotted about 450. Most of the finds include one, two or three enormous gas-filled planets orbiting a star.

But on Tuesday, a group of European scientists announced an unusual discovery. They say they have identified a solar system that is similar to ours.

Scientists have been studying lightning for hundreds of years. Although they have a pretty good idea about what causes it, there is still more to learn about these mysterious sparks of electricity.  

Given that summer is peak season for thunderstorms, it's probably a good idea to brush up on your lightning facts, particularly if you have some outdoor adventures planned.
 
Tornadoes and hurricanes are more dangerous than lightning
 
Myth: Lightning kills more people (about 58) each year than tornadoes or hurricanes. In fact, it is the most underrated weather hazard, according to the National Weather Service. Only floods are routinely responsible for more deaths than lightning.
 
You can get struck by lightning when you're inside

Fact: It's true that being inside a building when lightning strikes is your safest bet, but that doesn't mean you shouldn't take some precautions.

"The colors of the [paintings] are fresh, as if they were painted yesterday," said archaeologist Abdel-Hakim Karar.

Egyptian archaeologists on Thursday announced the discovery of the double tomb in an ancient cemetery near Cairo, Egypt's capital. The paintings found on the false doors helped archaeologists date the tomb to the 6th dynasty, the age of the pyramids.

Supervisors of the Mission

According to the inscriptions, the tomb held the remains of a father and son, Shendwas and Khonsu. They both served as heads of the royal scribes, a group that documented important events in Egypt's history. Most of what we know about ancient Egypt is due to the work of scribes.

When musician and amateur astronomer William Herschel first spotted the planet Uranus through his homemade telescope back in 1781, he believed he had discovered a comet. But right from the start, he knew it was no ordinary comet: it had no tail, and everyone knew comets had tails.

Herschel was both wrong and right. He was wrong to believe that no planets existed beyond the original five that the ancient Greeks had known. But he was right to believe that only comets have tails (at least when they're within close distance of the sun) and that planets never do.

That's the way it works in our solar system anyway. But since astronomers began discovering worlds orbiting other stars in the 1990s, it's become clear that our family of planets isn't the only possible kind. The first planets ever found outside of our solar system, called exoplanets, shattered that belief. The new worlds were huge, like Jupiter, but hugged their stars so tightly that they completed a full orbit in just a few days.