It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Wednesday, January 24, 2024
SPACE
James Webb Space Telescope reveals one of the most mysterious worlds in the universe might have a volcanic moon
Maiya Focht,Morgan McFall-Johnsen Tue, January 23, 2024
But this free-roaming world has no star, so scientists suspect a moon is shooting lava at it.
NEW ORLEANS — When astronomer Jackie Faherty peered into space using information from the James Webb Space Telescope, there was something she couldn't take her eyes off of.
Brown dwarf W1935, a world larger than Jupiter drifting alone in open space about 47 light-years from Earth, was letting off a methane signature unlike anything ever seen before.
Brown dwarfs are some of the most unusual and mysterious objects in space. They form like stars but don't grow massive enough to generate their own energy via nuclear fusion in their cores. For this reason, experts sometimes call them "failed stars." Brown dwarf W1935 may have aurora at its poles created by a volcanic moon that's orbiting the failed star.NASA, ESA, CSA, and L. Hustak (STScI)
The astronomers expected to see methane gas in the atmospheres of the brown dwarfs they were studying, but they didn't expect that any of the objects would actually emit methane.
The methane emission in the data "was like a pebble in a shoe. I couldn't get rid of it. I could only focus on this one feature," Faherty, who works at the American Museum of Natural History, said in a presentation at the 243rd meeting of the American Astronomical Society.
Methane emissions were discovered in the atmosphere of a brown dwarf.
NASA, ESA, CSA, and L. Hustak (STScI)
It's the first time such a methane fingerprint has appeared on a brown dwarf, Faherty said.
"For your typical brown dwarf just traversing the galaxy in solitude, your brown dwarf is very mysterious. It does not want to give away any of its secrets," said Austin Rothermich, a graduate student at the City University of New York, who presented other research on brown dwarfs at the conference.
But that methane hint may have given away one of this brown dwarf's biggest secrets: a volcanically active moon in its orbit. Jupiter and Saturn offer clues
Aurora on Jupiter's north pole.NASA, ESA, and J. Nichols (University of Leicester)
It turns out methane emissions, similar to those observed on W1935, are also found on Jupiter and Saturn.
On those two planets, the methane emissions are linked to aurora — the dancing lights that appear when charged particles from the sun interact with the planets' magnetic fields and atmospheres.
Faherty and her team concluded that this unusual brown dwarf likely hosts aurora, too. Northern lights, also called aurora borealis, dance in the sky over Tromso, Norway.NTB/Rune Stoltz Bertinussen/Reuters
But the mystery didn't end there.
Typically, to produce an aurora you need a nearby star. But there is no nearby star to W1935. So what was supplying the high-energy particles to power its aurora? An animation of the solar wind shows particles streaming from the sun towards Earth.NASA
Faherty and her team suspected a different kind of companion could be at work: an active moon.
Both Jupiter and Saturn have active moons that regularly eject material into space. Jupiter's moon Io erupts lava material into space while Saturn's Enceladus ejects geysers. Both types of material contribute to the two planets' auroras, and that's what could be happening with W1935, too.
"That does not mean that we're declaring that we have found an active moon, but it's one of the explanations," Faherty said.
Other possible solutions the team is exploring include free-floating matter in space, called interstellar plasma.
Whatever the reason may be, it takes very sensitive tools to detect brown dwarfs in the first place. So arriving at these conclusions would not have been possible without Webb, Faherty said.
"I don't think I emphasized this enough, these are so stinking faint. So faint. JWST was an absolute requirement to measure this," Faherty said.
Albedo closes $35M at boosted valuation to build satellites that orbit very, very close to Earth
Aria Alamalhodaei Updated Tue, January 23, 2024
Satellite startup Albedo aims to provide commercial orbital imagery so detailed that the military kept its own version under wraps — until it was leaked a few years ago by Donald Trump.
In 2019, then-president Trump tweeted a detailed image of a heavily damaged Iranian launch pad captured by a classified military satellite. The image, which was declassified in 2022, revealed what many in the commercial Earth observation industry suspected: that U.S. defense had the ability to capture images at a staggeringly sharp 10-centimeter resolution.
“When Trump tweeted a classified satellite image a few years ago that showed that we could capture 10-centimeter resolution from space, it sparked all this conversation in the commercial industry on how game-changing it would be to have that resolution commercially,” Albedo's co-founder and CEO Topher Haddad said in a recent interview. “I stumbled upon that conversation a while after it happened and basically couldn't get it out of my mind.”
At the time, Haddad was working on classified remote sensing satellites for the U.S. government at Lockheed Martin. A year later, Haddad teamed up with fellow Lockheed veteran AyJay Lasater and engineer Winston Tri to found Albedo, a company that’s aiming to do the impossible and deliver 10-centimeter resolution optical images to commercial customers at historically low costs.
(A 10-centimeter resolution essentially means that each pixel in an image covers an area the size of 10 centimeters by 10 centimeters on the ground. In comparison, the biggest optical imagery providers today collect images at a 30-centimeter resolution, which is algorithmically improved to 15 centimeters.)
Such low resolution, at a price the market will tolerate, is a big ask: The military satellites like the one that captured the image of the Iranian launch pad are widely believed to cost billions of dollars each. But Denver-based Albedo says it will be able to drive costs way, way down — not through big innovations on the optics side, but through its satellite bus platform that operates in very low Earth orbit (VLEO). That "is where the VLEO technology lives," Haddad said.
Instead of joining all the other Earth observation players and operating in low Earth orbit (LEO), the orbital band around Earth at an altitude of around 2,000 kilometers, Albedo is targeting the lesser-known (but aptly-named) VLEO that's between 250 and 450 kilometers. Albedo, which is almost entirely vertically integrated, has designed a satellite bus that is fully optimized for this environment: from the guidance, navigation and control (GNC) system; the robotics and software used to rapidly repoint the satellite and ensure images aren’t blurry; the solar arrays; and the mission planning and concept of operations to ensure that each satellite stays on orbit for an average of four years.
This last detail is key. While there are some upsides to operating in VLEO, like the fact that it’s less crowded and more protected from radiation, objects in that orbit are subject to a greater amount of atmospheric drag, since they are closer to Earth. But somewhat unintuitively, Albedo's satellites avoid this issue by being very dense and heavy, and by using an efficient electric propulsion system to counter the drag.
The biggest technical challenges, Haddad said, are actually in the robotics, control and attitude systems:
"There's three categories: there's stability, which is making sure your picture isn't blurry. There's agility, so being able to rapidly repoint at different targets that you're trying to image as you're passing over very quickly . . . And then there's accuracy, knowing exactly where you're pointed, which is related to [stability and agility] and also gives you that geolocation metric that certain customers care a lot about," Haddad explained.
“All those things at 10-centimeter resolution are just inherently very hard, because the angle from a single pixel is smaller than it would be for a 30-centimeter or 50-centimeter or three-meter. So any specific disturbance is going to impact the 10-centimeter pixel much more than a 30-centimeter pixel. Then you take that and you fly in VLEO, where the satellites are moving even faster around the Earth, there's torque from the atmosphere, all those things just pose an even harder challenge for GNC.”
Investors have rallied behind the company’s vision. In September 2022, a little less than a year after completing Y Combinator, Albedo announced it had raised a $48 million Series A round. Now the company says it has closed $35 million in Series A-1 financing, at an up-round valuation.
The use cases abound, from commercial to defense. Reflecting the dual-use nature of VLEO tech, Albedo’s investors include funds like Bill Gates’ Breakthrough Energy Ventures to defense tech-focused Shield Capital. This latest tranche was led by Standard Investments, the investing arm of industrial giant Standard Industries. New investors Booz Allen Ventures, Cubit Capital, and Bill Perkins also participated in this round, along with existing investors (like Breakthrough and Shield), as well as Initialized Capital, Y Combinator, Giant Step Capital, Republic Capital, and others. With this latest capital, the company’s raised $97 million to date.
Right now, Albedo is working toward launch of its first commercial satellite in the first half of 2025. Haddad declined to specify a timeline beyond that date but said that the company’s next goal would be to launch a block of six satellites that would provide a daily global revisit rate, and ultimately a full 24-bird constellation that would offer five revisits per day.
Atmospheric pressure changes could be driving Mars’ elusive methane pulses
Simulations will help Curiosity search for signs of past or present life on the Red Planet
New research shows that atmospheric pressure fluctuations that pull gases up from underground could be responsible for releasing subsurface methane into Mars’ atmosphere; knowing when and where to look for methane can help the Curiosity rover search for signs of life.
“Understanding Mars’ methane variations has been highlighted by NASA’s Curiosity team as the next key step towards figuring out where it comes from,” said John Ortiz, a graduate student at Los Alamos National Laboratory who led the research team. “There are several challenges associated with meeting that goal, and a big one is knowing what time of a given sol (Martian day) is best for Curiosity to perform an atmospheric sampling experiment.”
The paper was published the week of Jan. 22 in the Journal of Geophysical Research: Planets.
A primary focus of NASA’s Mars missions, including Curiosity and Perseverance, is to detect and understand past or present signs of life, such as methane. However, with the source of methane on Mars likely being underground, short-term variations in atmospheric methane levels have posed a research challenge.
To better understand Mars’ methane levels, Ortiz and his team used high-performance computing clusters to simulate how methane travels through networks of underground fractures and is released into the atmosphere, where it then mixes within the atmospheric column. They also modeled how methane is adsorbed onto the pores of rocks, which is a temperature-dependent process that may contribute to the methane level fluctuations.
Their simulations predicted methane pulses from the ground surface into the atmosphere just before the Martian sunrise in the planet’s northern summer season, which just recently ended. This corroborates previous rover data suggesting that methane levels fluctuated not only seasonally, but also daily.
This valuable data is helping inform the Curiosity rover’s ongoing sampling campaign.
“Our work suggests several key time windows for Curiosity to collect data. We think these offer the best chance of constraining the timing of methane fluctuations, and (hopefully) down the line bringing us closer to understanding where it comes from on Mars,” Ortiz said.
Paper: “Sub-diurnal methane variations on Mars driven by barometric pumping and planetary boundary layer evolution.” Journal of Geophysical Research: Planets. DOI: 10.1029/2023JE008043
Sub-Diurnal Methane Variations on Mars Driven by Barometric Pumping and Planetary Boundary Layer Evolution
ARTICLE PUBLICATION DATE
22-Jan-2024
Motion of satellite galaxies suggests younger universe
Peer-Reviewed Publication
CHINESE ACADEMY OF SCIENCES HEADQUARTERS
In standard cosmological models, the formation of cosmological structures begins with the emergence of small structures, which subsequently undergo hierarchical merging, leading to the formation of larger systems. As the Universe ages, massive galaxy groups and clusters, being the largest systems, tend to increase in mass and reach a more dynamically relaxed state.
The motions of satellite galaxies around these groups and clusters provide valuable insights into their assembly status. The observations of such motion offer crucial clues about the age of the Universe.
By using public data from the Sloan Digital Sky Survey (SDSS), a research team led by Prof. GUO Qi from the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) analyzed the kinematics of satellite pairs around massive galaxy groups. The team's findings suggest that the Universe may be younger than predicted by the LCDM model with Planck cosmological parameters.
This study was published in Nature Astronomy on Jan. 22.
The researchers investigated the movement of satellite pairs positioned on the opposite side of massive galaxy groups by using their velocity offsets from the central galaxy along the line of sight. They discovered a notable excess of pairs exhibiting correlated velocity offsets compared to pairs displaying anti-correlated velocity offsets.
"The excess of correlated satellite pairs suggests the presence of recently accreted or infalling satellite galaxies," said Prof. GUO Qi, the corresponding author of the paper.
This excess was also found in up-to-date cosmological simulations but the magnitude of this effect was considerably lower than in observations. The significant discrepancy between the observations and simulations implies that massive galaxy groups are younger in the real Universe.
"Since the age of the massive galaxy groups could be closely related to the age of the Universe, these findings consequently suggest a younger Universe compared to that derived from the cosmic microwave background (CMB) by the Planck Collaboration," said Dr. GU Qing, first author of the paper.
These findings present a challenge to the current cosmological model and may provide valuable insights into the Hubble tension problem.
This paper can be accessed at https://www.nature.com/articles/s41550-023-02192-6.
JOURNAL
Nature Astronomy
DOI
10.1038/s41550-023-02192-6
ARTICLE TITLE
A younger Universe implied by satellite pair correlations from SDSS observations of massive galaxy groups
ARTICLE PUBLICATION DATE
22-Jan-2024
Successful failure: Sierra Space's inflatable habitat blows up as planned
Aria Alamalhodaei Mon, January 22, 2024
Sierra Space has completed a key test of its inflatable space habitat, as the company progresses toward launching and operating a private space station with Blue Origin before the end of the decade.
The “ultimate burst pressure” test of the inflatable module was conducted at NASA’s Marshall Space Flight Center. As the name suggests, the purpose of the test is to inflate the unit until it bursts. In this instance, engineers inflated the module to 77 psi before it burst, proving that it exceeded NASA’s recommended safety level of 60.8 psi by 27%.
While Sierra has conducted a series of burst tests on sub-scale units of the habitat, called Large Integrated Flexible Environment (LIFE), this is the first on a full-scale module. At full scale, the module stands at over 20 feet tall and is around one-third the volume of the International Space Station.
As Leanne Thompson, a systems engineer at Sierra, pointed out in a recent video on the test, it took NASA 10 to 15 launches to send up that same volume of habitable space with the ISS. Each LIFE module is designed to fit inside a standard five-meter payload fairing, though the company said it is working on bigger iterations of 1,400 cubic meters (larger than the ISS) that could fit in a seven-meter fairing.
The test focused on the LIFE habitat’s pressure shell or restraint layer, which is made of expandable “softgoods” that perform like a rigid structure once they’re inflated. Softgoods as a materials category have aerospace heritage: There have been inflatable airlocks attached to the ISS, and demonstration modules developed by Bigelow Aerospace were launched to space in the 2000s.
The softgoods that make up the LIFE habitat include Vectran straps, which are made out of high-performance polymers and other materials. In a press release, Sierra said that Vectran is “stronger than steel when inflated on-orbit.” The company is working with ILC Dover to design and test the straps prior to this full-scale test.
Although the burst test is certainly suggestive, it would be a mistake to compare the LIFE module to a balloon. In the video above, Sierra briefly displays nine layers that will ultimately make up each module, including the restraint layer, such as thermal insulation and an outer cover.
Sierra’s plan is to deploy the LIFE modules in low Earth orbit as part of Orbital Reef, a private space station the company is developing with Blue Origin. Notably, Sierra specifically references the project in the press release, which could be at least partly a response to reporting from CNBC last year that the Orbital Reef project was on the verge of falling apart.
Sierra said this year will be one of “aggressive” testing at both sub- and full-scale of the other layers of the habitat.
An impossibly huge ring of galaxies might lead us to new physics. Here's how
Keith Cooper Mon, January 22, 2024 A view of the sky with one dotted blue circle toward the top center and a dotted red art to the middle left.
An intergalactic ring-shaped superstructure of galaxies and galaxy clusters — so large it defies explanation — has been discovered. This is a structure that lives so deep in the universe that we see it as it was some 9.2 billion years ago.
The huge superstructure, nicknamed the "Big Ring," spans 1.3 billion light-years in diameter and has a circumference of about 4 billion light-years. It is also close to another immense superstructure, the "Giant Arc in the Sky," which is actually even larger with a diameter of 3.3 billion light-years. The Giant Arc sits at a similar distance to us in the constellation of Boötes, the Herdsman. Alas, these superstructures are far too faint to be seen with a backyard telescope.
In fact, both superstructures were discovered in observations performed by the 2.5-meter telescope of the Sloan Digital Sky Survey at Apache Point in New Mexico, U.S. by Alexia Lopez. Interestingly, Lopez, a Ph.D. student at the University of Central Lancashire in the U.K., spotted the galaxies in these superstructures not because they are bright, but rather because they absorb some of the light emanating from more distant quasars. Quasars are the extremely luminous interiors of active galaxies; they're powered by supermassive black holes.
"Identifying two extraordinary ultra-large structures in such close configuration raises the possibility that together they form an even more extraordinary cosmological system," said Lopez in a statement.
The Big Ring isn't actually even a ring – it's coiled sort of like a slinky. Plus, we see it edge-on.
Still, the problem with the Big Ring and the Giant Arc (and other similar superstructures, for that matter) is they defy cosmological theory.
According to theory, all structures in the universe can be traced back to what's known as the cosmic microwave background (CMB) radiation — the so-called "fireball of the Big Bang" that scientists observe filling the universe. During the first 300,000 years of cosmic history, the universe was a sea of dense plasma — that is, atomic nuclei and free electrons. Waves crashed through this plasma, with matter bunching up at the peaks and becoming more sparse in the troughs. Scientists call these waves baryonic acoustic oscillations, or BAOs.
However, after those 300,000 years, the temperature of the universe cooled sufficiently to allow atomic nuclei to soak up most of the electrons and form complete atoms. You might say that the cosmic plasma ocean "dried up"; cosmologists call it the "epoch of recombination." Without the electrons that constantly scattered photons, light was able to pass unhindered through the universe for the first time. This is what we detect as the CMB.
The CMB is mottled with subtle temperature variations that correspond to regions of greater and lesser density. This is the imprint of the final acoustic waves that rippled through the plasma before the epoch of recombination. The peaks of the waves mark what we describe today as the "cosmic web of matter," and it was at these peaks where galaxies, and galaxy clusters, began to form. A graph with black dots strewn all over.
"One possibility is that the Big Ring could be related to baryonic acoustic oscillations," says Lopez. "[These] arise from oscillations in the early universe and today should appear, statistically at least, as spherical shells in the arrangement of galaxies. However, detailed analysis of the Big Ring revealed it is not really compatible with the BAO explanation: the Big Ring is too large and is not spherical."
Cosmological theory suggests that the largest structures — in the form of chains of galaxies and galaxy clusters — that BAOs could form should be, at most, 1.2 billion light-years in length. Yet, the circumference of the Big Ring and the length of the Giant Arc dwarf this constraint. To put into context how immense these superstructures are, the Giant Arc is one-fifteenth the radius of the whole, visible universe.
There are other huge superstructures in the universe too, such as the Sloan Great Wall, which is 1.37 billion light-years across and about a billion light years away from us. The South Pole Wall of galaxies is a more recently discovered structure; it's 1.4 billion light-years in length. Then there is the Clowes–Campusana LQG (co-discoverer Roger Clowes is also Lopez’s PhD advisor), which is a huge group of quasars spread across two billion light-years. We see these ancient quasars as they were some 9.5 billion years ago.
The Laniakea Supercluster, of which the Milky Way is a part, is tiny by comparison at just 520 million light-years across.
There are also hints of even larger structures; the "dark flow" represents the apparent motion of many galaxies in the visible universe. This motion seems to flow in a preferred direction, as though something over the cosmic horizon were pulling the galaxies one way. However, the strength of evidence for the dark flow is controversial, with some astronomers disputing its existence in general.
Nonetheless, these superstructures are so large that not only is it difficult to understand how they formed, but it's also hard to decode how they break the Cosmological Principle, a central tenet of the Standard Model of Cosmology. This principle states that, on large scales, the distribution of matter in the universe should be even and that no region should look substantially different from any other region. But clearly, the superstructures, and particularly the Big Ring and the Giant Arc, hugely stand out.
"Neither of these two ultra-large structures is easy to explain in our current understanding of the universe," said Lopez. "And their ultra-large sizes, distinctive shapes and cosmological proximity must surely be telling us something important — but what exactly?"
One possibility is that the structures are hinting at exotic forms of currently known physics, or perhaps even new physics. For example the Nobel Laureate Sir Roger Penrose, who is a professor emeritus at the University of Oxford, has suggested a model called Conformal Cyclic Cosmology to describe a cyclical universe. Per this model, evidence for gravitational waves from previous eons of the universe could manifest as giant ring-shaped structures in the CMB. Penrose's model has not proven popular among cosmologists, but could the Big Ring and Giant Arc give it a worthy shot?
Another possibility is that the superstructures are evidence for cosmic strings, which are hypothetical one-dimensional defects in spacetime believed to have formed during the Big Bang. Cosmic strings could potentially stretch across billions of light-years, yet be narrower than the width of a proton. It has been suggested that if cosmic strings exist, they could affect the clustering of matter.
"The Big Ring and the Giant Arc, both individually and together, gives us a big cosmological mystery as we work to understand the universe and its development," concluded Lopez.
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