Category: space

So then, as explained by RockDoctor (Slashdot reader #15,477) “they propose a number of standardised units of comparison for journalists describing ‘death from the skies'”.

An excerpt from that April 1 newsletter:
In the absence of a handy skyscraper, animals commonly used have included giraffes, corgis and an entire colony of penguins. But how do these comparisons stack up? Let’s look at some of our favourite unusual suspects:
– Corgi: At around 30 cm tall, a space rock the size of a corgi wouldn’t pose much of
a threat.
– Half a giraffe: An adult giraffe can reach up to 5.5 metres in height, so half a giraffe
would be about 2.75 metres. While not as impressive as a full skyscraper, an
asteroid that size could certainly destroy a building or two…
– Elephants: An adult African elephant can reach 7 metres at the shoulder. Ninety
elephants stacked on top of each other would form a staggering pile over 630
metres high, creating a devastating but probably not planet-ending event.

As this menagerie of animals can cause a lot of confusion, we at the NEOCC
recommend the use of a Standardised Giraffe Unit (SGU, 1 SGU = 5 penguins) for ease
of comparison.

RockDoctor shares this additional thought in his original submission about the newly proposed standardized unit.

“The world may be turtles all the way down, but it’s giraffes all the way up.”

To do this, the team needed a Rolls Royce of a digital camera. Mind you, the camera actually cost many million times that of an actual Royce Royce, and at 6,200 pounds (2,812 kilograms), it weighs a lot more than a fancy car. Each of the 21 rafts that makes up the camera’s focal plane is the price of a Maserati, and are worth every penny if they collect the sort of data scientists expect them to. “I’m personally most excited to study the expansion of the Universe using gravitational lenses to better understand Dark Energy,” said Aaron Roodman, a physicist at SLAC and lead on the camera program, in an email to Gizmodo. “That means two things: 1) measuring the brightness in all six of our filters of literally billions of galaxies and very carefully measuring their shape, which has been subtly altered by the bending of light by matter, and 2) discovering and studying very special objects where a distant quasar is almost perfectly lined up with a more nearby galaxy.”

Speaking through a SLAC release, Rodman said the camera’s images could “resolve a golf ball from around 15 miles away, while covering a swath of the sky seven times wider than the full moon.” The first images from the Rubin Observatory are slated to be publicly released in March 2025, which feels like a long way away. But several important agenda items still need to happen. For one, the SLAC team has to ship the LSST camera safely to Chile from its current lodgings in northern California. (Don’t worry — they’ve made a test run of the journey.) Then, the observatory’s mirrors need to be readied for testing and the observatory’s dome has to be completed, among some other tasks. But whenever all that is complete, the legacy survey will launch into a decade’s worth of scientific discovery. Rubin Observatory estimates suggest that LSST could “increase the number of known objects by a factor of 10,” according to a SLAC release.

The Big Ring on the Sky is 9.2 billion light-years from Earth. It has a diameter of about 1.3 billion light-years, and a circumference of about four billion light-years. If we could step outside and see it directly, the diameter of the Big Ring would need about 15 full Moons to cover it.

It is the second ultra-large structure discovered by University of Central Lancashire (UCLan) PhD student Alexia Lopez who, two years ago, also discovered the Giant Arc on the Sky. Remarkably, the Big Ring and the Giant Arc, which is 3.3 billion light-years across, are in the same cosmological neighborhood — they are seen at the same distance, at the same cosmic time, and are only 12 degrees apart on the sky. Alexia said: “Neither of these two ultra-large structures is easy to explain in our current understanding of the universe. 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 Big Ring could be related to Baryonic Acoustic Oscillations (BAOs). BAOs 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.” Other explanations might be needed, explanations that depart from what is generally considered to be the standard understanding in cosmology…

And if the Big Ring and the Giant Arc together form a still larger structure then the challenge to the Cosmological Principle becomes even more compelling… Alexia said, “From current cosmological theories we didn’t think structures on this scale were possible. ”

Possible explanations include a Conformal Cyclic Cosmology, or the effect of cosmic strings passing through…
Thanks to long-time Slashdot reader schwit1 for sharing the article.

But RockDoctor (Slashdot reader #15,477) calls the hypothesis “very much disputed.”
YouTubing-astrophysicist Dr Becky considered this report a couple of months ago (2023-Nov-09), under the title “HUGE blow for alternate theory of gravity MOND”. At the very least, astrophysicists and cosmologists are deeply undecided whether this data supports or discourages MOND. (Shortened comment because verification problem.)

Last week, I updated my annual count of MOND and other “alternative gravity” publications. While research on MOND (and others) continues, and any “suppression” the tin-foil-hat brigade want to scream about is ineffective, it remains an unpopular (not-equal-to “suppressed”) field. Generally, astronomical publication counts are increasing, and MOND sticks with that trend. If anything is becoming more popular, it’s the “MOG” type of “MOdified Gravity”.

RockDoctor (Slashdot reader #15,477) writes: A recent paper on ArXiv describes a Gamma Ray Burst (GRB) whose light arrived late last year as one of the strongest ever observed. GRB 221009A was detected on October 9 last year (yes, that number is a date), so 5 and a bit months from event to papers published is remarkably quick, and I anticipate that there will be a lot more papers on it in the future. Stand-out points are :
– it lasted for more than ten hours after detection (a space x-ray telescope had time to orbit out of the Earth’s shadow and observe it)

– it could (briefly) be observed by amateur astronomers.
– it is also one of the closest gamma-ray bursts seen and is among the most energetic and luminous bursts.

It’s redshift is given as z= 0.151, which Wikipedia translates as occurring 1.9 billion years ago, at a distance of 2.4 billion light-years from Earth.
Observations have been made of the burst in radio telescopes (many sites, continuing), optical (1 site ; analysis of HST imaging is still in work), ultraviolet (1 space telescope), x-ray (2 space telescopes) and gamma ray (1 sapce telescope) — over a range of 1,000,000,000,000,000-fold (10^15) in wavelength. It’s brightness is such that radio observatories are expected to continue to detect it for “years to come”.
The model of the source is of several (3~10) Earth-masses of material ejected from (whatever, probably a compact body (neutron star or black dwarf) merger) and impacting the interstellar medium at relativistic speeds (Lorentz factor 9, velocity >99.2% of c). The absolute brightness of the burst is high (about 10^43 J) and it is made to seem brighter by being close, and also by the energy being emitted in a narrow jet (“beamed”), which we happen to be near the axis of.
General news sites are starting to notice the reports, including the hilarious acronym of “BOAT — Brightest Of All Time”. Obviously, with observations having only occurred for about 50 years. we’re likely to see something else as bright within the next 50 years.
The brightness of the x-rays from this GRB is such that the x-rays scattered from dust in our galaxy creates halos around the source — which are bright enough to see, and to tell us things about the dust in our galaxy (which is generally very hard to see). Those images are more photogenic than the normal imagery for GRBs — which is nothing — so you’ll see them a lot.

The lights lasted about 40 seconds, remembered one witness who filmed the lights while enjoying a local brewery. The brewery then asked on Instagram if anyone could solve the mystery, the report continues:

Jonathan McDowell says he can. McDowell is an astronomer at the Harvard-Smithsonian Center for Astrophysics. McDowell said Saturday in an interview with The Associated Press that he’s 99.9% confident the streaks of light were from burning space debris.

McDowell said that a Japanese communications package that relayed information from the International Space Station to a communications satellite and then back to Earth became obsolete in 2017 when the satellite was retired. The equipment, weighing 310 kilograms (683 pounds), was jettisoned from the space station in 2020 because it was taking up valuable space and would burn up completely upon reentry, McDowell added….

He estimated the debris was about 40 miles high, going thousands of miles per hour. The U.S. Space Force confirmed the re-entry path over California for the Inter-Orbit Communication System, and the timing is consistent with what people saw in the sky, he added.

“These objects are way more massiveâ than anyone expected,” said Joel Leja, assistant professor of astronomy and astrophysics at Penn State, who modeled light from these galaxies. “We expected only to find tiny, young, baby galaxies at this point in time, but we’ve discovered galaxies as mature as our own in what was previously understood to be the dawn of the universe.”

Using the first dataset released from NASA’s James Webb Space Telescope, the international team of scientists discovered objects as mature as the Milky Way when the universe was only 3% of its current age, about 500-700 million years after the Big Bang…. In a paper published February 22 in Nature, the researchers show evidence that the six galaxies are far more massive than anyone expected and call into question what scientists previously understood about galaxy formation at the very beginning of the universe. “The revelation that massive galaxy formation began extremely early in the history of the universe upends what many of us had thought was settled science,” said Leja. “We’ve been informally calling these objects ‘universe breakers’ — and they have been living up to their name so far.”

Leja explained that the galaxies the team discovered are so massive that they are in tension with 99% of models for cosmology. Accounting for such a high amount of mass would require either altering the models for cosmology or revising the scientific understanding of galaxy formation in the early universe — that galaxies started as small clouds of stars and dust that gradually grew larger over time. Either scenario requires a fundamental shift in our understanding of how the universe came to be, he added. “We looked into the very early universe for the first time and had no idea what we were going to find,” Leja said. “It turns out we found something so unexpected it actually creates problems for science. It calls the whole picture of early galaxy formation into question.”
“My first thought was we had made a mistake and we would just find it and move on with our lives,” Leja says in the statement. “But we have yet to find that mistake, despite a lot of trying.”

“While the data indicates they are likely galaxies, I think there is a real possibility that a few of these objects turn out to be obscured supermassive black holes. Regardless, the amount of mass we discovered means that the known mass in stars at this period of our universe is up to 100 times greater than we had previously thought. Even if we cut the sample in half, this is still an astounding change.”

Phys.org got a more detailed explantion from one of the paper’s co-authors:
It took our home galaxy the entire life of the universe for all its stars to assemble. For this young galaxy to achieve the same growth in just 700 million years, it would have had to grow around 20 times faster than the Milky Way, said Labbe, a researcher at Australia’s Swinburne University of Technology. For there to be such massive galaxies so soon after the Big Bang goes against the current cosmological model which represents science’s best understanding of how the universe works. According to theory, galaxies grow slowly from very small beginnings at early times,” Labbe said, adding that such galaxies were expected to be between 10 to 100 times smaller. But the size of these galaxies “really go off a cliff,” he said….

The newly discovered galaxies could indicate that things sped up far faster in the early universe than previously thought, allowing stars to form “much more efficiently,” said David Elbaz, an astrophysicist at the French Atomic Energy Commission not involved in the research. is could be linked to recent signs that the universe itself is expanding faster than we once believed, he added.

This subject sparks fierce debate among cosmologists, making this latest discovery “all the more exciting, because it is one more indication that the model is cracking,” Elbaz said.

This means that C/2022 E3 (ZTF) has made a rare, once-in-a-lifetime journey to be close to Earth. “Most known long-period comets have been seen only once in recorded history because their orbital periods are so, well, long,” NASA says. “Countless more unknown long-period comets have never been seen by human eyes. Some have orbits so long that the last time they passed through the inner solar system, our species did not yet exist.”

Now, the recently discovered E3 comet, which has been seen with a bright greenish coma and “short broad” dust tail, is set to make its closest approach to the sun on January 12. It will make its closest approach to Earth on February 2. Astrophotographer Dan Bartlett managed to capture an image of the comet in December from his backyard in California. He was able to see “intricate tail structure” in the comet’s plasma tail, he said, and “conditions are improving.”

About 47 million light-years from where you’re sitting, the center of a black-hole-laden galaxy named NGC 1068 is spitting out streams of enigmatic particles. These “neutrinos” are also known as the elusive “ghost particles” that haunt our universe but leave little trace of their existence…. Nestled into about 1 billion tons of ice, more than 2 kilometers (1.24 miles) beneath Antarctica, lies the IceCube Neutrino Observatory. A neutrino hunter, you might call it. When any neutrinos transfer their party to the frigid continent, IceCube stands ready.

In a paper published Friday in the journal Science, the international team behind this ambitious experiment confirmed it has found evidence of 79 “high-energy neutrino emissions” coming from around where NGC 1068 is located, opening the door for novel — and endlessly fascinating — types of physics. “Neutrino astronomy,” scientists call it.

It’d be a branch of astronomy that can do what existing branches simply cannot.

Before today, physicists had only shown neutrinos coming from either the sun; our planet’s atmosphere; a chemical mechanism called radioactive decay; supernovas; and — thanks to IceCube’s first breakthrough in 2017 — a blazar, or voracious supermassive black hole pointed directly toward Earth. A void dubbed TXS 0506+056. With this newfound neutrino source, we’re entering a new era of the particle’s story. In fact, according to the research team, it’s likely neutrinos stemming from NGC 1068 have up to millions, billions, maybe even trillions the amount of energy held by neutrinos rooted in the sun or supernovas. Those are jaw-dropping figures because, in general, such ghostly bits are so powerful, yet evasive, that every second, trillions upon trillions of neutrinos move right through your body. You just can’t tell….

Not only is this moment massive because it gives us more proof of a strange particle that wasn’t even announced to exist until 1956, but also because neutrinos are like keys to our universe’s backstage. They hold the capacity to reveal phenomena and solve puzzles we’re unable to address by any other means, which is the primary reason scientists are trying to develop neutrino astronomy in the first place…. Expected to be generated behind such opaque screens filtering our universe, these particles can carry cosmic information from behind those screens, zoom across great distances while interacting with essentially no other matter, and deliver pristine, untouched information to humanity about elusive corners of outer space.

The team says their data can provide information on two great unsolved mysteries in astronomy: why black holes emit sporadic blasts of light, and neutrinos’ suspected role in the origin of cosmic rays.