Geocorona - a cloud of hydrogen atoms that orbits the Earth's atmosphere was found to extend up to 390,000 miles beyond the orbit of the Moon. For perspective, the orbit where the moon around the Earth goes as far as 239,000 miles.
'The moon flies around the Earth's atmosphere," said Igor Baliukin, the lead director of Russia's Space Research Institute. He further added that they were not made aware of this until they took the initiative to look into the observations made the SOHO spacecraft over two decades ago.
The Solar and Heliospheric Observatory (SOHO) is a joint project of the European and NASA probe. It was launched in December of 2005 to study the sun and the space weather conditions. It was aimed at helping people learn more about how the weather behaves in the Earth's atmosphere beyond what is seen and experienced on earth.
The team headed by Baliukin analyzed the data in the archives of SOHO gathered through the Solar Wind Anisotropies Instrument (SWAN). Specifically, they looked into the measurements of the Lyman-alpha radiation -- a type of ultraviolet light. The wavelength used by the Lyman-alpha radiation, the Earth's geocorona interacts with sunlight. It has become impossible to observe this from the Earth because its atmosphere blocks such type of interaction. (therefore, it is best to observe it from space)
This study has allowed the research team to map the extent of the Earth's geocorona and get a handle of the region's density. They have found that the geocorona becomes denser at the Earth's side during the day and they blamed it on the compression of solar radiation. However, the term "denser" in this case remains to be relative by definition.
"On Earth, scientists would call it the vacuum. However, the extra source of hydrogen falls short in significance to require another space exploration," Baliukin said.
Scientists have long known of the Earth's geocorona, but it was only recently that they learned of its extent. Back when NASA's Apollo 16 mission was launched in 1972, the reach of the geocorona was believed to be limited.
"At that time, astronauts on the surface of the moon were not aware that they were embedded in the outskirts of the Earth's geocorona," said Jean-Loup Bertauz, the co-author in the study. "This study becomes even more interesting when we continue to look for planets with potential reservoirs of what people need to survive that extends beyond the solar system that we know."
