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Hello, Aliens?

A new study says intelligent life may be more likely to exist than we realized.

A spiral galaxy has eight red spikes from a bright core, plus white dots against a black background.

NASA, ESA, CSA, and J. Lee (NOIRLab); image processing: A. Pagan (STScI)

Is this photo showing us a place where intelligent life exists?

Do aliens exist? A new study raises the possibility that intelligent life is much more common than scientists previously thought!

Scientists have long thought that the existence of humans (Earth’s intelligent life-forms) came about due to a rare and lucky set of conditions and events. This is based on a 1983 theory by a scientist named Brandon Carter. Carter started with the fact that Earth is about 4.6 billion years old, but humans did not exist until about 200,000 years ago. This led him to believe that humans could develop only after a few key conditions were met. And even after that, Carter believed, it took a long time for humans to appear. 

Carter believed that it takes so long for intelligent life to evolve that on most planets, the host star, which is needed for life, would have burned out before that could happen.  Luckily for us, we evolved while our Sun was still young—only a few billion years old.

But a team of scientists at Penn State University say they don’t believe it takes a long time for intelligent life to evolve once a planet is able to support it. In fact, they believe that if conditions are right, intelligent life will evolve. And that means it’s possible that intelligent life exists on any planet where conditions are right.

Rocky planets that are Earth sized are most likely to be able to support life. Scientists believe there are about 1 billion Earth-sized planets in our galaxy alone, and many of them are likely to be rocky. That doesn’t mean intelligent aliens are living on every one of those planets. But if the Penn State study is correct, it’s possible we’re not alone.

Did You Know?

Even the closest known habitable (livable) planets are still as many as 40 light-years (trillions of miles) from Earth.

White, yellow, orange, and blue lights are against a black background.

NASA/ESA/CSA/Kristen McQuinn (RU)

Pi Day Magic

It’s that time of year again. March 14 is Pi Day, when we honor all things pi.

Though it’s pronounced “pie,” the word pi doesn’t refer to a delicious dessert. Pi is a number that begins 3.1415926535 and has been calculated to 100 trillion digits to the right of that decimal point. But no one will ever calculate all those digits because there are an infinite number of them!

To simplify things, most people shorten pi to 3.14. That’s why March 14 (which is often written as 3/14) is celebrated around the world as Pi Day.

We can celebrate Pi Day by eating pie…or by measuring that pie. Hear us out.

A pie is shaped like a circle. If you measure the length across the widest part of the pie, that’s the diameter. And if you measure the length all the way around the pie, that’s the circumference.

Two pies roll into the frame and then roll out to reveal circles. Dotted lines mark the circumference of one circle and the diameter of the other.

© Stacy/stock.adobe.com; Photo illustration Encyclopædia Britannica, Inc.

If you divide the circumference by the diameter, you’ll get a number that’s very close to 3.14…no matter what size your pie is. This is true for any circle.

A pie is shown with an equation showing that the circumference divided by the diameter equals roughly 3.14.

© Stacy/stock.adobe.com; Photo illustration Encyclopædia Britannica, Inc.

Life on Other Planets

The cover of a magazine called Startling Stories shows giant green aliens on a ship invading Earth.

© Chronicle/Alamy

There’s no proof of intelligent life outside of Earth, but scientists have attempted to contact aliens. Learn more at Britannica!

WORD OF THE DAY

oppidan

PART OF SPEECH:

noun

Definition:

a resident of a town TOWNSMAN

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