The Earth’s atmosphere reached out to the point where the astronauts set foot on the moon has not completely escaped.
Astronaus Buzz Aldrin stood on the moon surface in Apollo 11 in 1969. Photo: NASA
Yuri Gagarin, Neil Armstrong, or recently Katy Perry, attracted attention with spectacular space trips. But technically, no one has ever left the earth’s atmosphere. The International Space Station (ISS), although it is considered an active in the space, is actually still moving through the atmosphere and the gravity is strongly equal to about 90% of the gravity in the sea level.
“The atmosphere of the Earth, where we live and breathe, do not end right above. It does not end at the top of Everest, nor does it end at the flight where the aircraft is flying. The atmosphere reaches far and is becoming more and more thin when it is high.
“When it reaches the position of the ISS station – a few hundred kilometers from the Earth – still enough atmosphere to pull the station slowly. If not accelerated with the rocket engine, it will fall back to the Earth due to air resistance,” Rowland added.
The international spatial boundaries recognized as the Kármán road at an altitude of 100 km compared to the Earth’s surface. However, although most of the Earth’s atmosphere is located under Karman street, it is not the ending point.
“Although there is really no clear boundary about the end of the Earth’s atmosphere and the space begins, most scientists use a boundary called Karman Street, located 100 km from the Earth’s surface, to indicate the transition point, because 99,99997% of the earth’s atmosphere is below this point,” NASA explained.
According to the study published in February 2019, using data from the Solar and Japanese Turkish spacecraft (SOHO) of NASA and the European Space Agency (ESA), the farthest part of the Earth atmosphere – a hydrogen atomic cloud called Geocorona – can really reach 629,300 km into space, far beyond the moon orbit.
This study found that at an altitude of about 60,000 km, there were still about 70 hydrogen atoms per cm3. Even when astronauts set foot on the moon, they are still in the earth atmosphere, although this number drops to only about 0.2 hydrogen atoms per cm3. When considering data from Soho, the team found that the atmosphere expanded to about 50 times the Earth radius.
“The moon still flew through the Earth’s atmosphere. We don’t know it until the observations that the SOHO spacecraft performed more than two decades ago,” Igor Baliukin expert from the Russian Space Research Institute, the main author of the study.
This issue becomes even more complex in terms of technical, both the Earth and the Moon are in the sun atmosphere. “If the question is ‘Where is the space starting?’ It depends on your point of view. The answer is at an altitude of about 640,000 km. But remember that the space above the threshold is not empty.