At the start of a new millennium, we find ourselves on the brink of the greatest adventure ever. Imagine a spacecraft landing on Europa, one of Jupiter’s icy moons, 500 million miles from Earth. Its mission? To search for alien life.

As humans, we’re curious by nature. We look up at the countless galaxies filled with billions of stars and wonder: Are we alone? Recently, a researcher at the SETI Institute detected a radio signal from beyond our solar system. This signal has been confirmed by multiple sites around the globe, and scientists are buzzing. What if we’re not alone?

Considering there are 400 billion stars in our Milky Way galaxy alone, it seems improbable that we are the only form of life. The thought that life forms can exist in extreme conditions—places previously inconceivable—also fuels this belief. Primitive life might be widespread in the universe, thanks to the number of stars that have planets orbiting them.

SETI researchers have spent decades trying to answer this burning question. With technology advancing, they’re more optimistic than ever. They’re using some of the world’s most sensitive and sophisticated radio telescopes to detect alien interstellar messages. Imagine scanning 28 million radio frequencies to hear a squeal—an indication of intelligent life.

Jill Tata and Seth Shostak are among those who have dedicated their lives to this search. Every day, they work with a sense of anticipation, hoping for that breakthrough signal. Despite no confirmed discoveries yet, they remain hopeful and prepared for success.

As technology and astronomical discoveries progress, the number of potential sources of alien messages grows. We’ve discovered over 20 planets outside our solar system in recent years, and this number is expected to grow. Scientists use massive telescopes to hunt for these planets, including the Kepler telescope, which may soon provide proof of Earth-like planets.

Finding an Earth-like planet, though, doesn’t guarantee it’s suitable for intelligent life. It could be too hot, too cold, or simply toxic. To understand what types of life might exist elsewhere, NASA researches the harshest places on Earth. They’ve found microorganisms surviving in boiling water or beneath rocks in extremely cold environments. If life can exist in such conditions on Earth, it might also thrive in similar environments on other planets.

Mars has been a focal point in the search for microbial life. Though past missions have found it to be hostile to life as we know it, the idea persists. Liquid water appears crucial, and there’s evidence Mars once had it. Upcoming missions will collect Martian rocks, which could finally answer whether life once existed there.

Meanwhile, deep underground on Earth, scientists have discovered microbial life thriving two miles beneath the surface, far from sunlight. This gives hope that similar life forms could exist on Mars or even Europa.

Europa, a moon of Jupiter, has a particularly enthralling potential. Its icy surface might hide an ocean, warmed by heat from its core. This environment could support life, analogous to the deep-sea vents on Earth which teem with unique organisms.

NASA plans to send a Europa lander to melt through the ice and explore these underwater regions. Images and data beamed back could reveal whether life exists in the icy waters beneath Europa’s surface.

But, while we search within our solar system, the quest for intelligent life extends beyond. Earth has been sending radio and TV signals into space for decades. Dan Wertheimer and others are trying to intercept any such signals from advanced civilizations out there.

Some like Stephen Hawking caution about the risks, but the consensus remains that advanced civilizations are likely peaceful. Direct contact with extraterrestrial life seems unlikely due to vast distances. Instead, we may “meet” through intercepted signals.

Ultimately, confirming extraterrestrial life—whether intelligent or microbial—would have a staggering impact on us. It could affirm our uniqueness or reveal that we’re one of many civilizations. Either way, the answer matters profoundly.