The Moon is inside Earth's atmosphere, European researchers say

Scientists examined data from 20 years ago to reach a startling new conclusion.

  • Observations made by the SOHO spacecraft over 20 years ago lead to a new discovery.
  • The Earth has a hydrogen envelope as part of its outer atmosphere called the geocorona.
  • The geocorona stretches well past the Moon, reveals a study.

We are more linked to the Moon than we've realized. It turns out that the outer part of the Earth's atmosphere stretches considerably past the lunar orbit. In fact, it goes as far as twice the distance to the Moon.

This discovery is a product of observations by the Solar and Heliospheric Observatory (SOHO) — a spacecraft launched in 1995 to study the sun, operated by the European Space Agency (ESA) and NASA.

Measurements taken over 20 years ago by SOHO got a fresh look in a new study, which came to remarkable conclusions. What the data showed is that the geocorona, a hydrogen envelope which wraps around our planet, extends up to 630,000 km (391,464 miles) away from it. This distance is 50 times the Earth's diameter.

Earth's geocorona from the Moon. An ultraviolet picture taken in 1972 with camera operated by Apollo 16 astronauts on the Moon. Image source: European Space Agency

Igor Baliukin of Russia's Space Research Institute, the lead author of the study on the subject, explained that "the moon flies through Earth's atmosphere."

The geocorona appears where the planet's atmosphere comes into contact with outer space. It's essentially a cloud of hydrogen atoms. Between 1996 and 1998, SWAN, an instrument aboard the SOHO spacecraft, was able to use its sensors to follow hydrogen signatures, thus pinpointing the edges of the geocorona

"Data archived many years ago can often be exploited for new science," said Bernhard Fleck, a European Space Agency SOHO project scientist. "This discovery highlights the value of data collected over 20 years ago and the exceptional performance of SOHO."

The extent of Earth's geocorona. Image source: ESA

Besides being transformative in understanding our own atmosphere, the discovery may be helpful in searching for planets with water beyond our solar system. Detecting the presence of hydrogen in their outer atmospheres can mean the presence of water vapor near the surface.

Check out more SOHO accomplishments over 20 years in space:

3D printing might save your life one day. It's transforming medicine and health care.

What can 3D printing do for medicine? The "sky is the limit," says Northwell Health researcher Dr. Todd Goldstein.

Northwell Health
Sponsored by Northwell Health
  • Medical professionals are currently using 3D printers to create prosthetics and patient-specific organ models that doctors can use to prepare for surgery.
  • Eventually, scientists hope to print patient-specific organs that can be transplanted safely into the human body.
  • Northwell Health, New York State's largest health care provider, is pioneering 3D printing in medicine in three key ways.
Keep reading Show less

Should you defend the free speech rights of neo-Nazis?

Former president of the ACLU Nadine Strossen discusses whether our society should always defend free speech rights, even for groups who would oppose such rights.

Sponsored by Charles Koch Foundation
  • Former ACLU president Nadine Strossen understands that protecting free speech rights isn't always a straightforward proposition.
  • In this video, Strossen describes the reasoning behind why the ACLU defended the free speech rights of neo-Nazis in Skokie, Illinois, 1977.
  • The opinions expressed in this video do not necessarily reflect the views of the Charles Koch Foundation, which encourages the expression of diverse viewpoints within a culture of civil discourse and mutual respect.
Keep reading Show less

Has a black hole made of sound confirmed Hawking radiation?

One of Stephen Hawking's predictions seems to have been borne out in a man-made "black hole".

Image source: NASA/JPL-Caltech
Surprising Science
  • Stephen Hawking predicted virtual particles splitting in two from the gravitational pull of black holes.
  • Black holes, he also said, would eventually evaporate due to the absorption of negatively charged virtual particles.
  • A scientist has built a black hole analogue based on sound instead of light.
Keep reading Show less
Big Think Edge
  • In some fundamental ways, humans haven't changed all that much since the days when we were sitting around communal fires, telling tales.
  • Although we don't always recognize them as such, stories, symbols, and rituals still have tremendous, primal power to move us and shape our lives.
  • This is no less true in the workplace than it is in our personal lives.