For nearly three decades, if we can still remember, Galileo spacecraft had departed the Earth and blasted off to Jupiter, prompting the Carl Sagan, an astronomer to create his novel experimentation. This novel experiment is to search for a life sign on Earth from the space above. 

Galileo spacecraft has found out a large amount of oxygen and methane, a suggestion that there is an occurrence of photosynthesis on the surface of the planet Earth. Inspired by this idea, in late 2017, the astronomers had repeated this kind of experiment, but this time with spacecraft that is said to be “asteroid-bound” that can swing around the planet. They found out that the Earth is packed with life but possesses a worrying corollary. They had observed that the methane and the carbon dioxides are far higher compared to the atmospheric levels they have during the flyby of Galileo.

According to Dante Lauretta, a scientist for the planets, the existence of such high amount is the challenging intellectual enterprise. The OSIRIS-Rex’ main goal is to get back the taken samples from Bennu, one of the asteroids that have the size of the Empire State Building. 

However, during the flyby that brings the spacecraft 22x closer to the Earth than the moon, the scientists had pointed their instruments towards the home. The team had seen hurricanes, as well as its spectrographs (an instrument used in order to detect the gases that are based on the absorption of the wavelengths of the lights passing our atmosphere), a level of methane, ozone, and oxygen that are far higher compared to the values anticipated to a world that life has no sings. 

These records are showing that the biological processes are creating the mentioned compounds according to the reports released by the team. Also, they had found out that the visible lights are being absorbed by the landmasses of the Earth, which is an apparent sign that photosynthesis takes place. 

In the update for the findings of the Galileo flyby, OSIRIS-Rex had recorded that carbon dioxide and ethane values are higher compared to their amount during 1990. Lauretta said that these values are no longer surprising. More than two decades ago, the world is just containing two billion people, which means there are only a few sources of pollutions around and only less are doing bad habits to ruin the atmosphere. But the numbers of people nowadays are exponentially growing that is why there is no surprise why these atmospheric changes take place.