Tag Archives: Galileo Galilei

Earth can be a model for detecting vegetation on exoplanets

Back in December 1990, during its flyby of Earth, NASA’s Galileo spacecraft, which studied the planet Jupiter and its moons, as well as several other Solar System bodies, pointed its instruments towards Earth, at the urging of Carl Sagan. And, it has found evidence of life on our planet. This can be a key to detect vegetation on exoplanets – which is a key to a possible intelligent extraterrestrial life.

In a paper published on Nature, researchers wrote “The Galileo spacecraft found evidence of abundant gaseous oxygen, a widely distributed surface pigment with a sharp absorption edge in the red part of the visible spectrum, and atmospheric methane in extreme thermodynamic disequilibrium. Together, these are strongly suggestive of life on Earth.”

Continue reading Earth can be a model for detecting vegetation on exoplanets

A Bowling Ball and Feather Falling in a Vacuum (video)

It’s one of the basic Newton laws: how fast something falls due to gravity is determined by a number known as the “acceleration of gravity”, which is 9.81 m/s2 at the surface of Earth. The acceleration of gravity, shortly “a” means that in one second, any object’s downward velocity will increase by 9.81 m/s because of gravity. The gravity accelerates everything at exactly the same rate.

This also means a heavy object like a bowling ball and a lightweight object like a feather should fall down with the same speed, regardless of their shapes. But we see this phenomenon very rarely in our daily lives. The reason is the air resistance. That’s why people (including Aristotle) thought that the heavier objects fall faster for thousands of years.

Continue reading A Bowling Ball and Feather Falling in a Vacuum (video)