On June 16, 1888, Alexander Friedmann was born in St. Petersburg, Russia. An keen student from a young age, Friedmann studied mathematics and meteorology at St. Petersburg State University and the Aerological Observatory in Pavlovsk. After air force service in World War I, Friedmann taught at several institutions and traveled to discuss his research. InContinue reading "Sept. 16, 1925: Death of Alexander Friedmann"
Dwarf galaxies—with a mass equal to about a billion suns, but often considerably less—are the most abundant in the universe. However, because of their low luminosity, they are very difficult to detect. They have mostly been discovered in the vicinity of the Milky Way, in what is called the Local Group, but also, and in large quantities, at greater distances, where current instrumentation cannot distinguish individual stars.
Dwarf galaxies—with a mass equal to about a billion suns, but often considerably less—are the most abundant in the universe. However, because of their low luminosity, they are very difficult to detect. They have mostly been discovered in the vicinity of the Milky Way, in what is called the Local Group, but also, and in large quantities, at greater distances, where current instrumentation cannot distinguish individual stars.
Astronomers using the James Webb Space Telescope have measured the most powerful gas outflow ever recorded from a "dead" galaxy outside our cosmic neighborhood and found that even outflows this extreme may not be enough to permanently shut down star formation.
Astronomers using the James Webb Space Telescope have measured the most powerful gas outflow ever recorded from a "dead" galaxy outside our cosmic neighborhood and found that even outflows this extreme may not be enough to permanently shut down star formation.
NASA’s Pandora satellite has started science observations of at least 20 exoplanets, measuring their host stars so Webb’s atmospheric results can be read more reliably.
Twelve entrances opened onto the horizon at Chleby. The excavators link their directions to the Sun and Moon, raising questions about how people gathered there.
Astronomers have confirmed that one of the fastest-changing stars ever observed has entered a new stage of its evolution, offering a rare opportunity to watch a star's life unfold on human timescales.
Astronomers have confirmed that one of the fastest-changing stars ever observed has entered a new stage of its evolution, offering a rare opportunity to watch a star's life unfold on human timescales.
Troy E. Meink’s comments were the first public acknowledgment of American weapons in orbit. The Pentagon has been preparing for potential conflict in space with Russia or China.
NASA's newly launched Nancy Grace Roman Space Telescope is set to extend its lifespan and double its exciting potential for discovery thanks to an efficient use of fuel on its way to its final orbit.
"As a result of exquisite planning by our orbital dynamics team, brilliant execution by the operations team, and a precise launch from SpaceX, Roman has fuel for at least 22 years of potential science operations," said Jamie Dunn, the center director at NASA's Goddard Space Flight Center, in a statement.
The space telescope, which launched from Cape Canaveral on Aug. 30 on a mission to measure dark energy and search for exoplanets, is headed to the L2 Lagrange point. There, it will join the likes of the James Webb Space Telescope on the opposite side of Earth to the sun. Its primary mission will last five years, and scientists were hoping for an additional five years if funding allowed.. Now, however, that potential extended mission could go on for a lot longer — and it's all thanks to the spacecraft coming in less massive than the original design had projected.
The Lagrange points depicted in a diagram. (Image credit: NASA Goddard Space Flight Center Scientific Visualization Studio)
At the beginning of Roman's design process, the fuel capacity was chosen to permit a maximum mass of 21,605 pounds (9,800 kilograms), yet the finished spacecraft came in lighter at 17,760 pounds (8,065 kilograms). And because it was lighter, there was a surplus of available mass that could be used for more fuel.
"A spacecraft's mass changes throughout the design and build process, so we base the propellant on a set maximum value so we won't come up short," Alison Rao, who leads Roman's propulsion systems at NASA Goddard, said in the statement. "We track the propellant needed based on actual mass throughout integration and testing as well, to make sure we have wiggle room. Since Roman's [mass] was lower than we budgeted for, we were able to fill the propellant tanks to their capacity rather than only filling them as much as we needed to for the 10-year requirement."
The extra fuel loaded onto the telescope before launch meant it had enough for at least a 14-year mission. Then, within a day of launching, the space telescope had to fire its engine for three minutes to push it onto a trajectory to take it to L2. This engine burn was more precise and hence more efficient than anyone could have hoped for, sending Roman on its way to L2 with 99% accuracy. In doing so, it used only 40 pounds (18 kilograms) of fuel, which is less than 10% of the 441 pounds (200 kilograms) of fuel that had been budgeted for the maneuver. This is thought to have bought Roman an additional four years of life, bringing the tally to 18 years.
Then there's the added bonus. The precision with which the Aug. 31 engine burn was conducted means that the second course correction, required to take Roman into its orbit at L2 in early December, will also now require much less fuel. This will add yet another four years to Roman's operational lifetime, so long as nothing goes wrong with the telescope. Once in orbit at L2, only minor burns once every 28 days are needed for station keeping — a negligible amount of fuel.
In total, this observatory could be probing the final frontier and making incredible discoveries for at least the next 22 years, taking it up to 2048 at minimum. For the next two or three decades, we're going to be hearing a lot about the Nancy Grace Roman Space Telescope.
This starry view of the nearby star-forming region IC 348 is one of the largest images released to date from NASA's James Webb Space Telescope. Using Webb, astronomers searched IC 348 for brown dwarfs, which are less massive than the smallest stars. The researchers discovered brown dwarfs just twice the mass of Jupiter, bringing the study of these curious objects into a new mass range and revealing new insights about the star-formation process.
The rings around a strange small body orbiting between Saturn and Uranus look mysteriously different from previous views, new observations from the James Webb Space Telescope (JWST) suggest.
The rings encircle Chariklo, which is a centaur, a strange type of object that shows characteristics of both asteroids and comets. Chariklo is only about 400 miles (250 kilometers) in diameter and is part of a large group of tiny objects in the distant solar system.
Scientists first discovered Chariklo's rings in 2013 — making it the first small solar system body found to have rings — and studied them with ground-based telescopes again in 2014 and 2017. When JWST took another look at Chariklo in 2022, a decade had brought a lot of difference, according to a study published Sept. 9 in the journal Science Advances.
"By comparing JWST observations with those obtained … over the last decade, we discovered opposite changes in the two rings: while the inner ring shows significantly higher opacity, the outer ring shows lower opacity, " Pablo Santos-Sanz, a researcher at the Institute of Astrophysics of Andalusia and first author of the study, said in a statement.
Researchers don't know exactly how the changes took place, but the study authors offered three suggestions. The first is that JWST, which has a fine resolution, was able to see both denser and sparser zones of the rings than previous observations showed. The second is that there were changes in the rings' material or in the grains themselves. Finally, a third possibility is that JWST could see "grains with wavelength-dependent optical properties," meaning the telescope saw effects in composition and grain size that explain the variability.
Santos-Sanz said the research suggests that small bodies with rings — even those orbiting far away from the gravitational influences of planets — may have more changes in their systems than scientists previously thought. "Our results force us to rethink how they form, how they evolve, and what mechanisms maintain their stability," he said.
A theoretical follow-up observation, taken the next time Chariklo passes in front of a star, would help to confirm the new JWST results, the researchers added — especially the apparent decreased opacity of one of the rings and the increased opacity of the other.
"These observations would help disentangle temporal evolution from wavelength-dependent scattering effects, and clarify the physical processes shaping Chariklo’s rings," the researchers stated in the study.
The new observations of Chariklo also mark the first time that scientists have planned a JWST viewing campaign specifically around a stellar occultation — that is, the researchers timed the viewing precisely to when Chariklo passed in front of a distant star from the telescope's point of view.
All observations of Chariklo's rings, on the ground and in space, have used stellar occultations. That's because the rings are too faint to be imaged directly, so astronomers must instead learn more about the rings by measuring the dips and increases in brightness as Chariklo passes in front of the background star. Scientists use a similar method to study the atmospheres of alien planets with JWST's infrared instruments.
Chariklo's speed relative to JWST was low, at 1.5 miles per second (2.5 kilometers per second), allowing for fine imaging of the rings. To time the occultation, the researchers used info from the European Space Agency's Gaia mission, which precisely charts the locations and movements of more than 2 billion stars, as well as calculated the orbit of JWST at a location roughly 930,000 miles (1.5 million km) from Earth in the opposite direction of the sun. According to the researchers, the planning and execution of the mission required "extreme precision."
Astronauts could travel back to Earth from Mars using rocket fuel converted directly from the carbon dioxide in the Red Planet's atmosphere, using a technique known as electrochemical reduction, a recent study reports.
It's an old method involving electrolysis, which is the application of an electrical current to drive a chemical reaction, but the new trick produces methane pure enough to be used as liquid propellant. (A number of rocket engines these days burn liquid oxygen and liquid methane — including the Raptors that power Starship, the rocket SpaceX is developing to help humanity get to Mars.)
"The work we're doing is basically taking CO2 and using electricity to convert it into carbon-containing fuels and chemicals," said Carter Racine in a statement. Racine is a Ph.D. student in mechanical engineering at Texas A&M University and a member of the study team, which was led by University of Mississippi chemical engineer Ahmed Badreldin.
"You can't bring up everything you need [on Mars] from Earth, because every additional kilogram adds enormous cost and complexity to launch and escape Earth's gravity," added Badreldin. "So the question becomes, How do we make the fuels and chemicals needed for space exploration from the resources already available at the destination?"
One answer is electrochemical reduction, which takes place in an electrolyzer, with electrons flowing from the negatively charged anode to the positively charged cathode. Water at the anode is oxidized, meaning it loses an electron, which is transferred to the carbon dioxide at the cathode, where one of its atoms gains an electron and becomes what chemists refer to as "reduced" (meaning its oxidation state is lowered). It can then react with the hydrogen and oxygen atoms that have split from the oxidized water molecules.
The anode contains a catalyst, and the choice of material for the catalyst dictates what carbon-based compounds are produced when the reduced carbon reacts with the hydrogen and oxygen. For example, a gold catalyst leads to the production of carbon monoxide (CO), while copper produces more complex compounds including alcohols, ethanol and methane (CH4).
What makes the work of Badreldin's team stand apart from previous experiments is that they have developed a nanometer-scale copper catalyst doped in nitrogen that is able to produce nearly pure methane.
Electrochemical reduction of carbon dioxide has been used to produce methane before, in applications on Earth. The problem is, those methods have produced a lot of byproducts alongside methane. On Earth we have complex equipment that separates the methane from the other unwanted compounds, but astronauts are not going to be able to take such unwieldy devices to Mars when every kilogram counts. That's a problem, because for methane to be used as a liquid propellant in rocket fuel it needs to be pure.
NASA wants to send astronauts to Mars in the late 2030s or early 2040s. (Image credit: NASA)
However, the specific copper catalyst used by Badreldin's team is able to preferentially produce methane over other compounds, thereby creating it pure without having to refine it. And there's plenty of carbon dioxide available on Mars to use: While Mars' atmosphere is thin, it is nonetheless composed of 96% carbon dioxide.
Even if astronauts never go to Mars, the usefulness of this technique on Earth is clear. Rather than drilling for this natural gas, we can create methane from the carbon dioxide already in our atmosphere.
"We want to do that because right now many of these carbon-based products ultimately come from virgin fossil resources," said Racine. "If we can make them using captured CO2 and renewable electricity, it could reduce reliance on virgin fossil carbon and help close the carbon cycle."
Consequently, electrochemical reduction has also been suggested for use on Earth as a carbon sequestration technique, drawing carbon dioxide out of our atmosphere where it acts as an unwanted greenhouse gas.
The problem with that is, converting carbon dioxide into methane to be burned as a fuel simply releases that carbon dioxide straight back into the atmosphere in a net-zero cycle. Ideally, we want to lock that carbon dioxide away from the atmosphere for a long period of time, but Badreldin doesn't think the technology is ready yet.
"What we are ultimately interested in is seeing whether we can move beyond simply recycling CO2 and toward pathways that are net-negative," he said. "That means using CO2 as a carbon source while converting it into products where the carbon is stored or used long enough that it is not immediately released back into the atmosphere."
It should be noted that the best way to alleviate climate change is to cease burning all fossil fuels, including methane. However, using methane created from electrochemical carbon dioxide reduction in a net-zero process rather than drilling for it could help during the transition from fossil fuels to renewable resources.
The study reporting this research was published in April in the journal ACS Catalysis.
A broad pit that looks almost like a "footprint" on Mars is unlike anything researchers have ever seen on the Red Planet. (Image credit: NASA/JPL-Caltech/MSSS)
Is that a footprint on Mars? Sorry to burst your bubble, but no. However, scientists have found a strange feature unlike anything they've seen before on the Red Planet's surface.
What is it?
While NASA's Perseverance rover is the newest addition to the agency's robotic Red Planet fleet, its cousin Curiosity is still going strong and finding strange and unusual things on Mars 14 years after landing.
In new observations captured on Mars' Mount Sharp, the Curiosity team has identified "features unlike quite anything we have seen in the past," Michelle Minitti, deputy principal investigator for Curiosity's Mars Hand Lens Imager (MAHLI), said in a statement.
These mysterious features are a bunch of broad, shallow pits scattered across the Martian bedrock.
Why is it incredible?
While little pits and divots are common to find on the Martian surface, these wide, shallow pits that researchers saw with Curiosity are quite different from surface features that have been seen before.
"The pits of this week were much broader and shallower than past features and were not accompanied by obvious objects that were once in the pits," Minitti said.
The team collected as much data as they could on the strange pits using Curiosity's various instruments, including MAHLI, the Mastcam camera, ChemCam (the Chemistry and Camera complex) and APX (Alpha Particle X-Ray Spectrometer).
They have so far found interesting layers in the pit material that seems chemically different from the main bedrock.
But we will have to wait and see what else researchers might be able to learn about these odd pits. How did they form? How long have they existed? What can they tell us about the history of Mars?
A giant 10-sided wave is emerging around Saturn’s south pole, giving scientists a rare chance to watch a planetary weather pattern take shape. NASA’s Hubble Space Telescope has detected a huge, evolving atmospheric wave with 10 sides wrapped around Saturn’s south pole. It is the first time scientists have seen a large, regular-sided jet pattern [...]
A new class of cosmic object observed by NASA’s Chandra X-ray Observatory could hold the key to unraveling two long-standing mysteries, astronomers say.
In a recent paper published in Nature Astronomy, researchers described these new cosmic objects as having high levels of ultraviolet radiation but low-intensity X-rays.
In the NASA Chandra data, the team identified 84 of these strange objects, which they dubbed “hypersoft X-ray sources,” across six galaxies. The unexpected discovery could finally help answer puzzling questions related to star formation and the expansion of the universe.
Chandra Sees Something New
“We’ve never encountered a group of objects that act like this,” said lead author Mustafa Muhibullah of the University of Alabama. “Of course, the next step was to try to figure out what these things are.”
The new research used data from a publicly accessible Chandra archive provided by NASA, including the spiral Andromeda and Pinwheel galaxies and an additional four elliptical galaxies. Intriguingly, both older regions and active star-forming regions contained the new objects.
The team discovered the objects by comparing Chandra’s high- and low-energy X-ray images to identify sources that were disappearing. Their departure from high-energy X-ray images indicated the objects were producing only low-energy X-rays, which border ultraviolet light on the spectrum. This led the researchers to then identify the high-energy ultraviolet radiation coming from the objects.
The Pinwheel galaxy hosts seven of the strange objects. Credit: X-ray: NASA/CXC/Univ. of Alabama/M. Muhibullah et al.; Optical: NASA/ESA/STScI; Image Processing: NASA/CXC/SAO/N. Wolk
Mystery Objects
Currently, the team cannot effectively determine what these objects are, but they do have some suspects, including black holes, neutron stars, or white dwarves pulling material from a companion. Such material would heat as it fell into one of the three suggested objects, theoretically producing the observed X-rays. While these types of binary systems have all been observed previously, this combination of ultraviolet radiation and low-energy X-rays hasn’t been associated with them.
Because the researchers found so many of these objects in just six galaxies, they suggest many more of these likely binary systems remain undiscovered across the universe.
These objects were not previously identified for two reasons. The more obvious is how faint their X-ray signature is, which requires extremely sensitive equipment to detect. The other is that helium and hydrogen gas between stars absorbs the stronger ultraviolet radiation, obscuring these otherwise brilliant signals.
“By combing through the Chandra archive, we were able to eliminate what used to be a blind spot for telescopes,” said co-author Rosanne Di Stefano, Senior Astrophysicist with the Center for Astrophysics, Harvard & Smithsonian. “That’s how we found what appears to be a new class of cosmic objects with remarkable qualities.”
What Did Chandra See?
“These clandestine X-ray sources are actually among the most energetic objects in galaxies, and they could be solving two cosmic mysteries at once,” said Muhibullah.
One of the mysteries this may solve ties to the rate of universal expansion itself. Type Ia supernova observations have provided astrophysicists with essential data indicating that the universal expansion is accelerating. Although they suggest these supernovae likely come from white dwarf binary systems, astronomers have never observed a star turning into one to confirm the hypothesis.
“If we could find a way to spot these Type Ia supernova explosions before they go off, that would be really important,” said co-author Jimmy Irwin, also of the University of Alabama. “Right now, we study them after they’ve exploded, and astronomers have struggled to understand what is actually ignited.”
The other mystery is what removes electrons from the free-floating gas between some stars, which could have major ramifications for star formation and galactic life cycles. Hot, massive stars were previously identified as likely partially responsible, but they couldn’t account for the full extent by themselves. The research team says hyper-soft X-rays and intense ultraviolet radiation could be the missing culprit.
Only continued observation and research can provide a definitive answer on the mystery objects that Chandra observed.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.
Login
