Alien-Hunting Telescope

Do aliens exist? If they’re out there, a new telescope in China may be our best bet for finding them. Completed this past September, the Five-hundred-meter Aperture Spherical Telescope (FAST) is the world’s largest radio telescope.

FAST detects radio waves, the same form of electromagnetic radiation used to broadcast music to your car stereo. Many objects in space—such as stars, galaxies, and clouds of gas and dust—emit radio waves. The telescope’s dish acts like a huge antenna to pick up these signals. It covers an area about the size of 30 football fields. That’s more than two-and-a-half times the size of the previous largest radio telescope (see Record-Breaking Telescopes).

The enormous size of China’s new telescope will help astronomers from around the world—including the U.S.—study fainter and more distant objects than ever before. They plan to use FAST to learn about unusual stars, study molecules in space, and hunt for signs of extraterrestrial life.

Do aliens exist? If they’re out there, a new telescope in China may be our best bet for finding them. The Five-hundred-meter Aperture Spherical Telescope (FAST) was completed this past September. It’s the world’s largest radio telescope.

FAST detects radio waves. That’s the same form of electromagnetic radiation used to send music to your car stereo. Many objects in space send out radio waves. These include stars, galaxies, and clouds of gas and dust. The telescope’s dish acts like a huge antenna to pick up these signals. It covers an area about the size of 30 football fields. That’s more than two-and-a-half times the size of the former largest radio telescope (see Record-Breaking Telescopes).

The huge size of China’s new telescope will create new possibilities for astronomers. They’ll be able to study space objects that are fainter and farther away than ever before. Scientists around the world hope to use FAST to learn about unusual stars and molecules floating in space. And they’ll hunt for signs of extraterrestrial life.

Radio waves allow astronomers to learn a lot about the universe. This form of energy can pass through barriers that visible light can’t. “On a foggy day, you may not be able to see very far in front of you,” says Joseph Lazio, an astronomer at NASA’s Jet Propulsion Laboratory in California. “But your car’s radio can receive signals broadcast from miles away.”

In space, clouds of dust block visible light but not radio waves. “Using visible light, we can’t even see halfway to the edge of our own galaxy, the Milky Way,” says Lazio. “But we can pick up radio waves from all the way across it.”

Radio waves are also one of the most promising ways to search for extraterrestrial life. The only example scientists have of highly intelligent life is right here on Earth: humans. Our technology—from television to cell phones—produces a lot of radio waves. Looking for radio waves elsewhere in the universe could help scientists find alien civilizations.

Radio waves allow astronomers to learn a lot about the universe. This form of energy can pass through barriers that visible light can’t. Joseph Lazio is an astronomer at NASA’s Jet Propulsion Laboratory in California. “On a foggy day, you may not be able to see very far in front of you,” he says. “But your car’s radio can receive signals broadcast from miles away.”

In space, clouds of dust block visible light. But they don’t block radio waves. “Using visible light, we can’t even see halfway to the edge of our own galaxy, the Milky Way,” says Lazio. “But we can pick up radio waves from all the way across it.”

Radio waves could also be one of the best ways to search for extraterrestrial life. Scientists have only one example of highly intelligent life. It’s right here on Earth: humans. Our technology—from television to cell phones—produces a lot of radio waves. So how might scientists find alien civilizations? By looking for radio waves in other parts of the universe.

When picking a spot for a radio telescope, a key goal is “getting as far away from people as possible,” says Lazio. Signals from objects in space can be weak. That’s one reason FAST is so big—so it can collect more radio waves from faraway sources. But things like cell phones, microwaves, and radio towers on Earth can cause interference. These devices give off their own radio waves. That background noise can make faint radio signals from space hard to detect.

To minimize interference, the FAST team selected an area in the mountainous Guizhou province of China. The site is in a karst region. This landscape is dominated by limestone, which erodes easily to form large, shallow valleys—some of which are just the right size and shape for a giant telescope dish. Surrounding mountains provide protection from interference. More than 9,000 people living in villages nearby were relocated to minimize human activity that could cause interference.

Scientists have to pick the right spot for a radio telescope. Lazio says a key goal is “getting as far away from people as possible.” Signals from space can be weak. That’s one reason FAST is so big. Its size allows it to collect more radio waves from faraway sources. But things like cell phones, microwaves, and radio towers on Earth can cause interference. These devices give off their own radio waves. That background noise can make faint radio signals from space hard to detect.

The FAST team wanted to reduce interference. So they chose an area in the mountainous Guizhou province of China. The site is in a karst region. This landscape is mostly limestone, which wears away easily to form large, shallow valleys. Some of these valleys are just the right size and shape for a telescope dish. The mountains around them block interference. More than 9,000 people lived in villages nearby. But they were moved to reduce human activity that could cause interference.

Workers began the construction of FAST’s massive dish in 2011. It consists of 4,450 triangular aluminum panels. Radio waves from space hit these panels and reflect onto receivers hanging above the dish. Cables beneath the dish can be used to adjust its shape, allowing astronomers to focus the telescope on specific targets they want to observe.

FAST’s engineers made the telescope’s first scientific observation, often referred to as “first light,” early last year. The dish wasn’t finished yet, but the team focused it on a distant cloud of gas and dust called the Crab Nebula. They were able to pick up radio signals from a pulsar, a rotating star that shoots out a beam of radio waves, within the nebula.

“A pulsar is one of the most extreme objects in the universe,” says Lazio. “It’s like a lighthouse more massive than the sun that releases radio waves while spinning up to 700 times a second.” Studying pulsars will be a big part of FAST’s mission. Scientists hope to learn about unusual forms of matter that make up these stars and test ideas about the structure of the universe.

Workers started building FAST’s huge dish in 2011. It’s made of 4,450 aluminum panels. Radio waves from space hit these panels. Then the waves reflect onto receivers that hang above the dish. Astronomers can use cables under the dish to change its shape. This allows them to focus the telescope on different targets.

A telescope’s first scientific observation is called “first light.” FAST’s engineers reached this goal early last year. The dish wasn’t finished yet, but the team focused it on a distant cloud of gas and dust called the Crab Nebula. They picked up signals from a pulsar inside it. A pulsar is a spinning star that shoots out a beam of radio waves.

“A pulsar is one of the most extreme objects in the universe,” says Lazio. “It’s like a lighthouse more massive than the sun that releases radio waves while spinning up to 700 times a second.” A big part of FAST’s mission will be studying pulsars. Scientists hope to learn about unusual forms of matter that make up these stars. They also want to test ideas about the makeup of the universe.

One of the most exciting parts of FAST’s work is the hunt for extraterrestrial life. Existing telescopes are already searching, but FAST’s sensitive dish will add new capabilities.

Since nobody knows what a signal from an alien civilization might look like, astronomers will investigate any observation FAST makes that seems out of the ordinary. If researchers detect an unusual signal and can’t find an explanation for it, they’ll share the observation with other scientists for analysis.

No official global policy exists on what to do if a signal really does seem to be extraterrestrial. But many astronomers have agreed to informal guidelines on how to handle the situation. These involve informing the United Nations and other organizations. Then world leaders can decide whether to try to send a response to alien beings on behalf of humanity—and what that message should say.

Now that FAST’s giant eye is watching, we may be closer than ever to finding signs of life beyond our home planet.

One of the most exciting parts of FAST’s work is the hunt for extraterrestrial life. Other telescopes are already searching, but FAST’s sensitive dish will add new power.

Nobody knows what a signal from an alien civilization might look like. So astronomers will check out any observation FAST makes that seems strange. If they can’t find an explanation for an unusual signal, they’ll share the observation. Then more scientists will try to figure it out.

What if a signal really does seem to be extraterrestrial? There aren’t any official global rules on what to do. But many astronomers have agreed to informal guidelines on how to handle the situation. They’ll inform the United Nations and other organizations. Then world leaders can talk it over. They’ll decide whether to try to send a response to alien beings from humans—and what that message should say.

Now FAST’s giant eye is watching. And we may be closer than ever to finding signs of life beyond our home planet.