Are we alone in the universe?
We are living in the time when we can finally ask the question: Are we alone in the universe? We have only recently learned about planets beyond our own solar system and even more recently discovered that some of these exoplanets could be habitable. Our search for life on other planets is still ongoing, but scientists think it’s very likely that there’s something out there. Here is what you need to know about this exciting new field of research!
Scientists continue to search for life beyond Earth.
As you’ve no doubt heard, scientists are actively searching for life beyond Earth. The search for extraterrestrial intelligence (SETI) has been ongoing since the 1950s, with radio telescopes scanning the skies in search of artificial signals from alien civilizations. Several missions have also been launched to explore Mars and other planets in our solar system with instruments that can detect signs of life—or at least evidence that conditions were once suitable for it to exist.
Other researchers are looking farther afield, examining how we might detect biosignatures on exoplanets orbiting other stars by studying their atmospheres or spectra (evidence of light refracting through a planet’s atmosphere). And some even speculate that we could find evidence of an intelligent civilization on another planet using gravitational lensing caused by a massive object like a black hole.
Scientists continue to search for life beyond Earth because there is so much more to learn about our own planet and solar system than we currently know. We have only begun our journey into space exploration; as more knowledge is gained about what lies within our own backyard—the solar system—we will grow closer to understanding what exists outside it: possibly finding answers about whether or not there is extraterrestrial life out there somewhere waiting for us to discover it!
Are we alone in the universe?
In attempting to answer whether we are alone in the universe, it helps to consider what the question means and what our current knowledge of space exploration can tell us.
The Drake equation is a formula developed by Frank Drake that estimates the number of intelligent civilizations in our galaxy (and beyond). It takes into consideration factors such as:
The number of stars in our galaxy
The fraction with planets that could support life
The fraction with planets on which life actually evolves
The fraction with intelligent beings capable of communicating across interstellar distances
What are the odds we are alone?
In the vastness of space, it’s easy to feel like we’re alone. But if you look at each planet and moon in our solar system, there is a good chance that life exists on some of them. If we go one step further and think about all the other planets in our galaxy, then that number grows exponentially! And if we consider how many galaxies there are in our universe? Well, that number becomes so large it’s almost impossible to comprehend…but still!
Life has thrived on Earth in a variety of extreme environments.
Life on Earth has thrived in a variety of extreme environments. In addition to our planet’s surface and atmosphere, life thrives in the deep ocean, the arctic, and deserts. And it’s not just Earth that provides examples of extreme life; we’ve discovered that on other planets as well we have found evidence of life thriving in similar types of environments (for example, at the bottom of lakes on Mars).
Notable scientists think we might find life elsewhere in the universe.
There are many notable scientists who believe there is life in the universe. These include Stephen Hawking, Carl Sagan and Neil deGrasse Tyson. Some of these scientists think that life will be found on Earth and in our solar system. Others think it will be found in another solar system or galaxy.
One of these prominent thinkers is Elon Musk, CEO of SpaceX and Tesla Motors. In an interview with Charlie Rose at TED Talk from 2012 (video below), Musk explains his thoughts about finding alien life: “I think we’re all going to learn something new about the universe.” He then goes on to say he thinks humans need to become “a multi-planetary species” in order for us not just survive but thrive among other planets and stars so that if anything happens here on Earth or if one day someone gets into trouble here—like falling overboard a boat or something—then they have somewhere else they can go because otherwise all our eggs would be in one basket.”
NASA is looking for signs of life in the solar system and beyond.
NASA is already looking for signs of life in the solar system and beyond.
NASA’s spacecraft have found evidence that water exists on Mars, Europa, and Enceladus–all moons of Jupiter.
Water is essential to life as we know it, so finding water elsewhere could mean something is alive there too.
Scientists think it’s very likely that life is out there somewhere else in the universe, but they just don’t know much about it yet.
Maybe you’ve heard scientists say that life on Earth is too rare to exist anywhere else in the universe. But this isn’t true. In fact, it’s very likely that life exists somewhere else in our galaxy: the Milky Way!
Scientists have found organisms living at extreme temperatures and pressures deep underground on Earth, so we know it’s possible for life to exist under all sorts of conditions. We also know that there are billions of other planets out there that could be similar to ours—they might even have liquid water and an atmosphere (which is key for supporting life). So while we don’t know exactly how many different forms of alien life could exist, scientists have a good idea what kinds of environments they might live in and where they may be hiding!