Habitable Planets

the right distance from a star for an atmosphere to form

the right distance from a star for a terrestrial planet to form

the right distance and temperature for liquid water

the right distance to protect a planet from the sun's UV rays

at a much greater distance

at a much smaller distance

at a much higher temperature

at a much lower temperature

Earth-sized

terrestrial planet

Within its stars habitable zone

gas giant

they are too long lived

they are short lived and run out of hydrogen fuel quickly

they are too bright

they do not produce enough heat

the habitable zones would be so close that planets would be tidally locked

the habitable zones would be so close that planets would not orbit

the habitable zones would be so far that the planets would be too cold

the habitable zones would be very narrow, so it is unlikely any planets would be in it

Around giant, hot stars

Around small, cool stars

Around sun-like stars (average size and temperature)

Around white dwarfs

carbon dioxide, sulfuric acid

methane, nitroxide

glucose, sulfur dioxide

water vapor, oxygen, ozone

habitable zone

mid-sized stars like our sun

mid-sized planets like our Earth

atmospheres of the right thickness

causing tides

stabilizing Earth's axial tilt

causing seasons on Earth

blocking Earth from the sun's UV rays

the Earth's axis is tilted about 23.4 degrees

the Earth wobbles on it's axis from 0-90 degrees

the Moon's gravity causes seasons

the Earth orbiting the sun causes seasons