Unlike Earth, every new planet we have discovered has been hostile to us. Some could become habitable if we figure out the answers to a few problems, like the unavailability of oxygen and water. Others would still be unsuitable for human life.

These deadly planets are ready to kill any creature that strays too close or tries to develop on them. Most of the planets on this list are not just too hot or cold. They have more terrible conditions that will never support life.

1. HD 189733b

In 2005, astronomers discovered a Jupiter-sized exoplanet, HD 189733b, with a distinctive Earthlike blue tint 63 light-years away. However, unlike Earth, HD 189733b was not blue because of its seas and oceans. Instead, the color came from its silicate-rich clouds.

HD 189733b is also deadly. The first problem is the 8,700-kilometer-per-hour (5,400 mph) winds that blow across the exoplanet. That is seven times the speed of sound, which is insanely fast. For comparison, peak sustained winds of the notorious Hurricane Katrina blew at 280 kilometers per hour (175 mph).

Then there is the rain. The silicate-rich clouds of HD 189733b cause rain of molten glass to fall from the skies. That rain does not fall straight down because of the superfast winds we just talked about. Instead, this strange precipitation falls sideways.[1]

Even if we somehow found our way around that, we would still need to deal with the high temperatures on the exoplanet. HD 189733b is so close to its star that it is ridiculously hot. To put that in better perspective, it is so near to its sun that HD 189733b completes a revolution around its star in just 2.2 Earth days. Interestingly, a day on this exoplanet is also 2.2 Earth days long.

The gravitational interaction between a planet and its star can cause a planet to have a day and year of the same length if the planet becomes tidally locked to its star, just as our Moon is tidally locked to the Earth. This means that the planet rotates on its axis in the same amount of time that it takes to complete one revolution around its star. (Rotations cause days and nights, and revolutions cause years.)

A tidally locked planet always keeps the same side toward its sun. So, one side is condemned to nonstop daytime while the other has perpetual nighttime.

2. CoRoT-7b

Tags: Science, universe, solar system, space, earth science, physics, science, science, science

In February 2009, astronomers operating the Convection, Rotation and Planetary Transits (CoRoT) satellite discovered a new exoplanet in the Monoceros constellation 480 light-years away from Earth. They called it CoRoT-7b.

CoRoT-7b is a rocky, Earthlike exoplanet even though it used to be a Saturn-sized hot Jupiter—a term used to describe the huge, gas-filled planets outside our own solar system with tight orbits around their stars. Despite having a rocky surface that could support life, CoRoT-7b is not the place to be.

For starters, its atmosphere is filled with minerals that form rock clouds. These clouds send pebbles and small rocks falling from the skies as if they were rain. Even if humans managed to survive that, they would be destroyed by the insanely hot surface temperature of the exoplanet.

Our own Earth is 60 times farther from our Sun than CoRoT-7b is from its star. In the daytime, the star in the skies of CoRoT-7b appears 360 times bigger than our own Sun looks from here on Earth. Talking about daytime, CoRoT-7b may also be tidally locked to its star. A day and a year are just 20.4 hours long.[2]

As you may have guessed, this means that half the exoplanet permanently faces its star. The surface temperature of that side is between 1,980 degrees Celsius (3,600 °F) and 2,300 degrees Celsius (4,220 °F), which is enough to melt rock. Astronomers believe that the rocks on the side facing the sun are molten because they can’t remain solid at that temperature… Show More

Tags: Science, universe, solar system, space, earth science, physics, science, science, science