Space News & Blog Articles

Sometimes it’s hard to remember that NASA also does atmospheric research too. While typically thought of as the province of the National Oceanic and Atmospheric Administration (NOAA), America’s space agency also has a vested interest in exploring our atmosphere and in the technologies that enable us to do so. As such, its NASA Institute for Advanced Concepts (NIAC) program provided a Phase I grant to a team from the University of Pennsylvania to develop a novel type of propulsion using only light to collect data in the Earth’s challenging-to-explore mesosphere.

The mesosphere is the part of the atmosphere that ranges from 50 km to 80 km, and it has several disadvantages for current exploration technologies. It’s too high for balloons or typical aircraft to reach, making standard high-altitude exploration technologies impractical. It’s also too low for satellites, as their orbit would degrade too quickly in its relatively thick soup of molecules, making the other typical space-based sensing platform impractical as well. The only way researchers have been able to explore it so far is through research rockets that only traverse it for a few minutes before falling back to Earth.

Enter a new technology from the lab of Dr. Igor Bargatin, a professor of mechanical engineering at the University of Pennsylvania. The technology takes advantage of a phenomenon known as photophoretic levitation to float devices simply by hitting them with light. 

That propulsion technology might sound similar to that used on a solar sail, but the delicate layers of foil used on solar sails would die a horrible death in the Earth’s atmosphere. The photophoretic effect, which has been known for almost a century, uses the heating of a solid compared to the ambient gas as a lifting force. As Dr. Bargatin’s press release on the NIAC website states, “The [photophoretic] force creates lift in structures that absorb light on the bottom yet stay cool on the top.”

Dr. Bargatin’s lab’s contribution to this century-old science is to make the first macroscale demonstration of a system using this technology. Previous attempts had all been on the micrometer scale, as the lifting force is extraordinarily weak, making it difficult to exert any significant lifting force on whatever payload it might be attached to. 

A team of astrophysicists has discovered a binary pair of ultra-cool dwarfs so close together that they look like a single star. They’re remarkable because they only take 20.5 hours to orbit each other, meaning their year is less than one Earth Day. They’re also much older than similar systems.

We can’t see ultra-cool dwarf stars with the naked eye, but they’re the most numerous stars in the galaxy. They have such low masses that they only emit infrared light, and we need infrared telescopes to see them. They’re interesting objects because theory shows stars this close together should exist, but this system is the first time astronomers have observed this extreme proximity.

“It’s amazing to see something happen in the universe on a human time scale.”

A team of astronomers presented their findings at the 241st Meeting of the American Astronomical Society in Seattle. Chih-Chun “Dino” Hsu, an astrophysicist at Northwestern University, led the research. The system is named LP 413-53AB.

“It’s exciting to discover such an extreme system,” said Chih-Chun “Dino” Hsu, a Northwestern astrophysicist who led the study. “In principle, we knew these systems should exist, but no such systems had been identified yet.”

A citizen science initiative called Globe at Night has some sobering news for humanity. Our artificial light is drowning out the night sky for more and more people. And it’s happening more rapidly than thought.

Globe at Night is an international citizen science project run by the National Science Foundation’s NOIRLab. It raises awareness about light pollution and how it’s impacting our view of the night sky. A new research article based on observational data from Globe at Night shows that the average night sky grew 10% brighter each year in artificial light for the past eleven years. And as our artificial light becomes brighter, more stars are becoming obscured.

The paper is “Citizen scientists report global rapid reductions in the visibility of stars from 2011 to 2022,” and it was published in the journal Science. The lead author is Christopher Kyba, a researcher at the German Research Centre for Geosciences.  

“The introduction of artificial light probably represents the most drastic change human beings have made to their environment.”

We should be able to see several thousand stars on a clear night. We should be able to see the grand arc of the Milky Way, too. But that’s becoming increasingly difficult for more and more people. Our growing artificial lighting is responsible, but it’s difficult to measure with satellites. A lot of our artificial light spreads horizontally, which satellites can’t measure effectively.