Are We "Home Alone" in a Galaxy of Billions of Planets?

Over the past few hundred years, Earth has been demoted from its former position as the center of the cosmos.

We now know that we are probably merely one of the trillions of planets in the Milky Way galaxy, and one of the smaller ones at that, in an era of rapid scientific discovery.

But Earth continues to be exceptional and unique thus far.

Despite intensive exploration of the solar system and the thousands of exoplanets that have been confirmed by our increasingly sophisticated telescopes, our planet is still the only one that is known to support life.

It's an embarrassment of riches in some ways.

From the boiling, corrosive lakes of Yellowstone National Park to the Dry Valleys of Antarctica, Earth's plentiful, tenacious, and ubiquitous lifeforms appear to occupy nearly every nook and cranny.

Only a few hundred million years, or an eyeblink in geologic time, may have passed since the formation of Earth from a spinning disc of gas and dust.

The evolution of Earth However, Earth hasn't always looked like the familiar blue globe.

In some ways, the diversity of competing species that have evolved over billions of years paints a picture of the various planets Earth has been, including a lava-covered rock with a toxic atmosphere, an ocean world with the earliest forms of microbial life, a steaming tropical riot of earth-shaking dinosaurs, or an Ice Age expanse where cave-dwelling humans hunted mammoths.

 According to Doug Hudgins, program scientist for NASA's Exoplanet Exploration Program at NASA Headquarters in Washington, "We prefer to talk about Earth-like worlds as a planet as ours is today." "

The world has occasionally changed dramatically in the past."

Compare the vibrant past of Earth to a brilliant galaxy that stretches out forever in all directions but is still mute on the existence of life.

nothing at all.

Life's search: What we know and don't know With more than 4,000 verified exoplanets in our galaxy, around one-fifth of them in the range of sizes of Earth, the odds appear a little better currently.

Water is one of the known components of life that can be found across the solar system and the cosmos.

We don't know when life first emerges, if it's frequent or rare, or how long it lasts.

The more intelligent life there is, the more questions there are.

One of the most well-known queries of all is: Where is everyone?

Currently, the Milky Way galaxy has 14 billion stars.

While the development of technological intelligence on our planet took more than 4 billion years, there are many planetary systems in the galaxy that are both similar in age and much older.

We hope you'll journey with us as we explore the planets and stars beyond our solar system.

We'll assess the current state of the search for life through stories and images, and we'll get a sneak peek at the space telescopes, experiments, probes, landers, rovers, and cutting-edge technology NASA wants to use in the ensuing decades.

The objective is to locate that elusive blue and white marble, or even an orange one—another planet that is alive and breathing.

 According to Nancy Kiang of the NASA Goddard Institute for Space Studies, who investigates how plants might adapt to extra-terrestrial settings, "our planet is the only example we have to follow."

Convergent evolution on a planetary scale "may be a similar evolutionary route (on other worlds)."