EXPLORE: Life Outside of Earth (BrainPop)

Remote sensing technology (for example, satellites and telescopes) have helped scientiests in their search for life on distant planets. Telescopes measure how these planets reflect the light and heat of their stars, which informs them of the atmospheric composition of that planet. This information can tell scientists about the "fingerprints" or specific chemicals that make up the planet's atmosphere and whether or not the ones that could potentially support life are present.

But scientists also consider the atmospheric makeup of supports types of life that existed in Earth's past. For example, scientists believe hat Earth's atmosphere originally did not include oxygen for the first 2 billion years or so. In fact, the gases that made up Earth's early atmosphere - carbon dioxide and ammonia compounds that came from ancient volcanic eruptions - would not support life as we know it today. Earth's atmosphere evolved to include oxygen and an ozone layer, making our planet suitable for life as we know it. This shows that atmospheric oxygen is not the only ingredient necessary for life. Carbon is generally thought of as the most fundamental element for life. Carbon is the basis for proteins and amino acids, life's building blocks.

Knowledge about the diverse settings and extreme environments in which life exists on Earth guides scientists in their search for where life might exist elsewhere in our solar system.