We are truly living in a new golden age of astronomy.
Many wondrous and strange places in the Solar System have been explored, thanks to the Hubble telescope and dozens of NASA missions to planets and large objects circling our Sun.
But what sorts of worlds are out there beyond the Solar System?
More than two thousand new worlds have been discovered to date using a variety of new techniques and technologies.
Their diversity has surprised astronomers and their strangeness staggers the imagination: hot gas giants larger than Jupiter orbiting their suns in such close orbits their year lasts only one Earth week.
Planets with diamond mantles supporting oceans of tar. Worlds completely covered in ice; other worlds covered in oceans of volcanic lava.
Even “Tatooine” planets with two suns lighting their skies have been found (to the delight of Star Wars fans everywhere).
While plenty of Earth-like, rocky planets have also been discovered, we haven’t yet found a world exactly like our own or seen evidence of alien civilizations.
But the sheer size of the Universe and the billions of possible planets out there means that life certainly exists on other worlds.
What that life might look like and where it might live are the questions that astrobiologists hope to answer.
Within our Solar System there are several places on which the search for extraterrestrial life is focused.
The most well studied thus far is our near neighbor, Mars, which may have primitive life forms locked in ice or living deep underground.
Jupiter’s moons Ganymede and Europa are thought to have underground oceans. Saturn’s moon Enceladus has a deep liquid ocean under its frozen exterior.
Even Saturn’s strange moon Titan has the presence of complex organic compounds in its methane seas.
Ironically, it’s our home world, Earth, that might provide insights into what alien life might look like.
Our planet has many examples of “extremophiles,” life forms that live and thrive under extreme conditions: giant tube worms that live at the base of scalding hot geothermal vents.
There are life forms colonizing methane ice and countless bacteria that thrive in environments too acidic, too hot or too cold for anything else to live.
A particularly hardy critter, the Tardigrade, a type of micro-animal, can be frozen for years and be revived unharmed, and can survive the vacuum of space!
Who knows what – or who – might be living out there on other worlds?
If you would like to learn more about scientists’ search for exoplanets and the search for extraterrestrial life, here are my six top picks from among the newest and most fascinating books on hand at the library:
What might life look like on other worlds? It’s possible to make predictions by studying 'extremophiles' on Earth, organisms such as the near-indestructible water bears (tardigrades) that can survive in the harshest conditions that Earth, and even space, can offer.
Exoplanets: Diamond Worlds, Super Earths, Pulsar Planets, and the New Search For Life Beyond Our Solar System
In Exoplanets, astronomer Michael Summers and physicist James Trefil explore some really amazing recent discoveries: planets revolving around pulsars, planets made of diamond, planets that are mostly water, and numerous rogue planets wandering through the emptiness of space.
The Planet Factory describes in detail the detection techniques used to find other planets in our galaxy. We can even detect clues about their surface environments and atmospheres, and whether this hints at the tantalizing possibility of life.
The Aliens Are Coming is an entertaining guide to the search for alien life. It makes the case that our growing understanding of life itself will help us predict whether it exists elsewhere, what it might look like, and when we might find it.
This biography celebrates the fascinating life and work of visionary astronomer Jill Cornell Tarter, founder of SETI (the search for extraterrestrial intelligence) and the inspiration for the character of Ellie Arroway in the novel by Carl Sagan and movie Contact, starring Jodie Foster.
Thousands of planets have been found outside the Solar System, yet we still do not know if any of them could support life. Now, armed with powerful technology, planet hunters are racing to find a true twin of Earth. Mirror Earth follows the dedicated planet hunters to find Earth's twin.