Researchers discover hot hydrogen atoms in Earth's upper atmosphere

Illinois researchers discover hot hydrogen atoms in Earth's upper atmosphere
A schematic diagram of the Global Ultraviolet Imager observational geometry. The TIMED satellite is orbiting at 625 km and viewing in the anti-sunward limb direction. Credit: Jianqi Qin, University of Illinois

A team of University of Illinois researchers has discovered the existence of hot atomic hydrogen (H) atoms in an upper layer of Earth's atmosphere known as the thermosphere. This finding, which the authors report in Nature Communications, significantly changes current understanding of the H distribution and its interaction with other atmospheric constituents.

Because H atoms are very light, they can easily overcome a planet's gravitational force and permanently escape into interplanetary space. The ongoing atmospheric escape of H atoms is one reason why Earth's sister planet, Mars, has lost the majority of its water. In addition, H atoms play a critical role in the physics governing the Earth's and also serve as an important shield for societies' technological assets, such as the numerous satellites in , against the harsh space environment.

"Hot H atoms had been theorized to exist at very high altitudes, above several thousand kilometers, but our discovery that they exist as low as 250 kilometers was truly surprising," said Lara Waldrop, an assistant professor of electrical and computer engineering and principle investigator of the project. "This result suggests that current atmospheric models are missing some key physics that impacts many different studies, ranging from atmospheric escape to the thermal structure of the upper atmosphere."

The discovery was enabled by the development of new numerical techniques and their application to years' worth of remote sensing measurements acquired by NASA's Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite.

"Classical assumptions about upper atmospheric physics didn't allow for the presence of hot H atoms at these heights," recalled Jianqi Qin, the research scientist who developed the data analysis technique. "Once we changed our approach to avoid this unphysical assumption, we were able to correctly interpret the data for the first time."

Atomic hydrogen efficiently scatters ultraviolet radiation emitted by the sun, and the amount of scattered light sensitively depends on the amount of H atoms that are present in the atmosphere. As a result, remote observations of the scattered H emission, such as those made by NASA's TIMED satellite, can be used to probe the abundance and spatial distribution of this key atmospheric constituent. In order to extract information about the upper atmosphere from such measurements, one needs to calculate exactly how the solar photons are scattered, which falls into Qin's unique expertise.

Under support from the National Science Foundation and NASA, the researchers developed a model of the radiative transfer of the scattered emission along with a new analysis technique that incorporated a transition region between the lower and upper extents of the H distribution.

"It turns out that the new model fits the measurements perfectly," said Qin. "Our analysis of the TIMED data led to the counter-intuitive finding that the temperature of the H atoms in the thermosphere increases significantly with declining solar activity, in contrast to the ambient atmospheric temperature, which decreases with declining solar activity."

Their results also show that the presence of such hot H atoms in the thermosphere significantly affects the distribution of the H atoms throughout the entire atmosphere. The origin of such hot H atoms, previously thought not to be able to exist in the thermosphere, is still a mystery.

"We know that there must be a source of hot H , either in the local thermosphere or in more distant layers of the atmosphere, but we do not have a solid answer yet," said Waldrop.

Qin added, "We will definitely keep working on this puzzle, because knowledge about the H density distribution is critical to the investigation of our atmospheric system as well as its response to space weather, which affects many space-based technologies that are so important for our modern society."


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More information: Jianqi Qin et al, Non-thermal hydrogen atoms in the terrestrial upper thermosphere, Nature Communications (2016). DOI: 10.1038/ncomms13655
Journal information: Nature Communications

Citation: Researchers discover hot hydrogen atoms in Earth's upper atmosphere (2016, December 6) retrieved 23 October 2019 from https://phys.org/news/2016-12-hot-hydrogen-atoms-earth-upper.html
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Dec 06, 2016
"This result suggests that current atmospheric models are missing some key physics that impacts many different studies, ranging from atmospheric escape to the thermal structure of the upper atmosphere."

Whaaaaat? How can this be? I've been lectured to that AGW is settled science yet this "significant" aspect of the atmosphere was ignored? I guess nothing is settled.
"Classical assumptions about upper atmospheric physics didn't allow for the presence of hot H atoms at these heights,"... "Once we changed our approach to avoid this unphysical assumption, we were able to correctly interpret the data for the first time."

This is a lesson that needs to be learned by astrophysicists and their approach to apply their unphysical assumptions of the plasma that constitutes 99.999% of the Universe. Unphysical assumptions is why astrophysicists are missing 96% of their Universe and we wallow in the Dark Ages of Cosmology.

Dec 06, 2016
This comment has been removed by a moderator.

Dec 07, 2016
@eu pseudoscience cult
their approach to apply their unphysical assumptions of the plasma
1- astrophysicists make educated logical hypothesis about plasma based upon experimental data that is repeatedly validated through testing and experiment in places like this: http://www.pppl.gov/

2- your eu cult has no viable theory (as defined by science) that can make predictions - so why keep discussing it?

3- if the eu were even semi-viable, you would be presenting peer reviewed journal papers from a reputable source to validate your claims instead of linking pseudoscience opinion or historical quotes that are falsified

4- repeating your lies don't make them more true, & posting them to a Science news aggregate does not make them legitimate

electric universe is a cult
- you can't provide science or evidence for your claim
- your arguments are repeated rhetoric
- you can't validate or predict anything
- you ignore falsification of your beliefs

Dec 07, 2016
Repeating lies helps validate (prop up & maintain) delusions.

Dec 07, 2016
Repeating lies helps validate (prop up & maintain) delusions.

You got that right, astrophysicists have been doing this for decades.

Dec 07, 2016
Atomic hydrogen is not ionized, so cd85's jumping on the plasma bandwagon is a bit premature.

Dec 07, 2016
Hmmm, well barakn nowhere did I say that what they discovered was plasma, although the "hot" designation they impart would suggest it is ionized. What I did do was point out that astrophysicists have their own "unphysical assumptions" about the matter they deal with, plasma, 99.999% of the time.
That being said, let's see what the authors of the papers has to say about your point;
"A rigorous theoretical understanding of the hydrogen geocorona has been a challenging geophysical problem that requires expertise in a wide range of disciplines, such as statistical mechanics, fluid mechanics, plasma physics, atmospheric chemistry and collision theory1,3."

So it would seem the authors are on the "plasma bandwagon", maybe you should sign up for a ride...

Dec 08, 2016
@eu cult preacher
What I did do was point out that astrophysicists have their own "unphysical assumptions" about the matter they deal with, plasma, 99.999% of the time
and again, regurgitating this lie doesn't make it more true
this has been proven as a false claim for years already - so why you continue to repeat it while ignoring the evidence is irrational as well as demonstrative of your learning disabilities (or some other mental degradation)

just one link completely debunks all your claims about "unphysical assumptions" [sic]
http://www.pppl.gov/

Dec 08, 2016
Hmmm, well barakn nowhere did I say that what they discovered was plasma, although the "hot" designation they impart would suggest it is ionized.

No, it wouldn't. A hydrogen atom has only one electron. If the atom becomes ionized, it is no longer an atom, it is not even referred to as hydrogen, it is a bare proton.

Dec 08, 2016
A hydrogen atom has only one electron. If the atom becomes ionized, it is no longer an atom, it is not even referred to as hydrogen


Really? Well, you have some work to do in enlightening the world to your statement;
https://en.m.wiki...I_region

http://astronomy....hydrogen

Isn't that special....

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