The extreme cold of Antarctica makes it one of the most challenging places on our planet to survive. Did you know that Antarctica is also considered the largest, and one of the driest, deserts on Earth? Click on image for full size (31 Kb) Image courtesy of NASA.

Extreme environments are places that are inhospitable to most "normal" living creatures. Extreme environments are not necessarily lifeless. Certain types of organisms, known collectively as "extremophiles", have adapted to survive or even thrive in various types of extreme environments.

Familiar extreme environments include deserts, mountain peaks, caves, and the frozen realms of the Arctic and Antarctic. Some environments are very hot or very cold, extremely dry, or both. Other environments are highly acidic or alkaline, are exposed to high levels of radiation, are under tremendous pressure, or are otherwise hostile to "normal" life.

Some extreme environments are hostile to life in multiple ways. Most deserts are both hot and dry, while the Dry Valleys in Antarctica are extremely cold and dry. Some hot springs are exceptionally acidic as well as scaldingly hot. Hydrothermal vents on the sea floor lack sunlight, spew forth scalding water, are chemically exotic, and are subjected to the crushing pressures of the deep oceans.

Early in our planet's history, most environments on Earth were extreme by modern standards. Likewise, environments on alien worlds within our Solar System and beyond are often marginally habitable if at all. Discoveries of life in recent decades in many extreme, and previously thought sterile, environments on Earth have sparked new interest in the study of life in exotic locales. Such study may help us learn about the history of life on Earth as well as the possibility of life on other planets. Astrobiologists also use extreme environments on our planet as analogs for other worlds (such as Mars) to test life-sensing instruments and techniques before implementing them on space missions.

This picture shows the continent of Antarctica. Most of Antarctica is an extreme environment. I'll bet you know that Antarctica is very cold. Did you know that most of it is very dry, too? Antarctica is considered the largest desert on Earth! Click on image for full size (31 Kb) Image courtesy of NASA.

Extreme environments are places where "normal" life finds it hard to survive. That doesn't mean that there isn't any life in extreme environments. Certain creatures can live and grow in extreme environments. Scientists have a special name for creatures that live in extreme environments. They are called "extremophiles".

What kinds of environments are "extreme"? Some extreme environments that you may know about are deserts, mountain peaks, caves, and frozen places like the Arctic and Antarctic. Some environments are very hot or very cold, extremely dry, or both. Other extreme environments are filled with acids, are blasted with radiation, are under high pressure, or are tough places for most living things in various other ways.

Some environments are extreme in more than one way. Most deserts are both hot and dry. The Dry Valleys in Antarctica are very cold and dry. Some hot springs are acidic as well as being nearly boiling hot. Hydrothermal vents on the sea floor don't receive any sunlight, spew out hot water filled with harsh chemicals, and are weighed down by the crushing pressure of the deep oceans.

When Earth was young, most environments on our planet were extreme compared to today. Environments on many other planets and moons within our Solar System and beyond are also extreme. In the last few decades, scientists have discovered life in extreme environments on Earth where they had thought it would be impossible for creatures to survive. Those discoveries made scientists more interested in studying extremophiles. Studying life in extreme environments may help us learn more about the history of life on Earth. It may also help us learn about the possibility of life on other worlds. Some extreme environments on Earth are a lot like extreme environments on other planets. Sometimes scientists test instruments for detecting life in extreme environments on Earth before they send them to other planets on space missions. For example, some instruments that are now on robots on Mars were first tested in the very, very dry Atacama Desert in Chile.

This picture shows the continent of Antarctica. Most of Antarctica is an extreme environment. I'll bet you know that Antarctica is very cold. Did you know that most of it is very dry, too? Antarctica is considered the largest desert on Earth! Click on image for full size (31 Kb) Image courtesy of NASA.

It is easy for living creatures to survive and grow in some places. Other places make it tough for life to get by. Scientists call places that are hard on life "extreme environments".

What kinds of places are "extreme environments"? Some that you may know about are deserts, mountain peaks, caves, and frozen places like the Arctic and Antarctic. Some environments are very hot or very cold, extremely dry, or both. Other extreme environments are filled with acids, are blasted with radiation, are under high pressure, or are tough places for most living things in lots of different ways.

Just because an environment is extreme doesn't mean there is no life there. Certain creatures can live and grow in extreme environments. Scientists have a special name for creatures that live in extreme environments. They are called "extremophiles".

Some environments are extreme in more than one way. Most deserts are both hot and dry. The Dry Valleys in Antarctica are very cold and dry. Some hot springs have acids in them and are nearly boiling hot. Hydrothermal vents on the sea floor don't get any sunlight, shoot out hot water filled with harsh chemicals, and are weighed down by the crushing pressure of the deep oceans.

When Earth was young, most environments on our planet were extreme compared to today. Environments on many other planets and moons within our Solar System and beyond are also extreme. In the last few decades, scientists have discovered life in extreme environments on Earth where they had thought it would be impossible for creatures to survive. Those discoveries made scientists more interested in studying extremophiles. Studying life in extreme environments may help us learn more about the history of life on Earth. It may also help us learn about the possibility of life on other worlds. Some extreme environments on Earth are a lot like extreme environments on other planets. Sometimes scientists test instruments for detecting life in extreme environments on Earth before they send them to other planets on space missions. For example, some instruments that are now on robots on Mars were first tested in the very, very dry Atacama Desert in Chile.