A thoroughly discredited idea, that the Mesoamerican Olmec people were Black Africans, continues to gain traction.
The elliptical galaxy NGC 1270 lies about 240 million light-years away. But it’s not alone. It’s part of the Perseus Cluster (Abell 426), the brightest X-ray object in the sky and one of the most massive objects in the Universe.
NGC 1270 plays a starring role in a new image from the Gemini North telescope. However, the image doesn’t show the dark matter that has a firm grip on the galaxy and the rest of the galaxies in the Perseus Cluster.
Ancient astronomers would be astounded by what we’ve learned about the Universe. Even astronomers like Edwin Hubble from the 20th would be amazed at the power of our modern telescopes and what they’ve shown us. At that time, distant galaxies appeared fuzzy and were called nebulae. Even the nature of Andromeda, our closest galactic neighbour, was uncertain. In 1920, Hubble and others were debating whether Andromeda and other objects they were seeing were small objects in the Milky Way’s outer regions, nebulae, or other galaxies.
German philosopher and Enlightenment thinker Immanuel Kant coined the term ‘island Universes’ to describe all these fuzzy objects, hinting at their true nature. The idea of other galaxies beyond our own dates back a long way, but there was no way to test it. Then, in 1924, Edwin Hubble ended the debate. He was able to show that individual stars in some of these so-called “nebulae” were actually far beyond the Milky Way.
The discovery was decisive, and we now know that the Universe is populated by hundreds of billions or even trillions of other galaxies like our own Milky Way.
Now, astronomers use powerful telescopes to examine other galaxies in great detail. They’ve even used the James Webb Space Telescope to peer back in time at the Universe’s earliest galaxies. Anyone can quickly examine hundreds of amazing images of other galaxies of all types.
Enormous objects like the Perseus Cluster alert us to the presence of something even more mysterious and challenging to understand than the nature of galaxies. Something binds these individual galaxies together into a coherent group, and we call that dark matter.
There’s a growing chorus of scientific voices suggesting we stop calling it dark matter and instead use the more accurate term invisible matter. But whatever we decide to call it, dark matter makes up most of the matter in the Universe and dwarfs the “normal” matter that interacts with light and makes up stars, planets, and us.
As cosmology has progressed, scientists have mapped the universe’s large-scale structure. These maps show how galaxies and their groups are organized along filaments of dark matter that act as scaffolds. The Perseus Cluster is associated with the Perseus-Pegasus Filament, a long, thin structure of galaxies that stretches over a billion light-years.
A computer model of the large-scale structure of the universe using the Illustris simulator. This image depicts the dark matter and gas involved in forming galaxies and galaxy clusters, as well as the filaments connecting them. Image Credit: Illustris TNGIf there were no dark matter, scientists think that the Universe would be far more homogenous. The galaxies would be spread more evenly throughout space. But that’s not what we see, and NGC 1270 and the rest of the Perseus Cluster show it clearly.
Currently, scientific theory suggests that a web of invisible dark matter draws galaxies together. They’re situated where dark matter’s massive tendrils intersect. That’s where its gravitational pull is strongest.
In short, the Perseus Cluster and NGC 1270 wouldn’t be where they are and wouldn’t be grouped together without dark matter. The cluster, and all other groups, clusters, and super-clusters, are firmly in dark matter’s grip.
American astronomer Vera Rubin played a huge role in our modern understanding of dark matter. She observed that stars and gas at a galaxy’s outer edge were moving much faster than predicted by the visible mass of the galaxy. Newtonian physics suggests they should be moving slower. Rubin and her colleagues thought that there must be a large amount of invisible matter beyond the visible edges of galaxies. Eventually, she figured out that there must be six times more dark matter than visible matter in galaxies.
Rubin faced many obstacles in getting her results accepted. As a woman, she wasn’t part of the male-dominated world of 1970s astronomy. She was denied access to some facilities early in her career, which slowed her progress. Now, she’s given full credit and mentioned alongside Hubble and other influential figures in astronomy. One of the most powerful and unique observatories ever conceived is named after her.
Regardless of what we call it and who discovered it, our Universe is dominated by something we don’t fully understand.
It’s remarkable that scientists can map invisible matter by its inference alone, without knowing what it is. The most widely accepted understanding of dark matter is in the Lambda Cold Dark Matter (Lambda-CDM) model of cosmology, also called the Standard Model of Big Bang Cosmology. It successfully recreates many things that we observe in the Universe, including how galaxies form, how the Universe expands, and, of course, the large-scale structure of the Universe.
But even Lambda-CDM can’t tell us what dark matter is. Most think it’s some type of particle, but if it is, it’s extremely elusive.
That doesn’t stop us from seeing its effect when we observe objects like NGC 1270 and the Perseus Cluster.
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Ships passing in the night used Morse code sent with lanterns and shutters to communicate. That same basic principle has allowed NASA to communicate with Psyche, its mission to a metal-rich asteroid in the main belt. However, the “light” was a version of heat, and instead of being able to see each other, Psyche is 240 million miles away from Earth. Oh, and the upload rate of the data it sent is still better than old dial-up internet connections that were prevalent not so long ago.
This feat was part of the culmination of the first Phase of NASA’s Deep Space Optical Communications experiment. Psyche is carrying a laser transceiver tuned to a specific frequency of infrared light, which can also be transmitted and received by two ground stations based in California. The infrared frequency the mission planner at NASA’s Jet Propulsion Laboratory selected is much higher than the typical radio frequency communications used for deep space missions. In this case, higher frequency also means higher data rate.
As part of its Phase I operations, the experiment transmitted data to and from Psyche at an astonishing 267 megabits per second when the spacecraft was as far away as Mars when the Red Planet is closest to us. That is equivalent to a typical wired broadband connection back here on Earth. But it was made in space – with lasers.
Video that Psyche sent back to Earth.In June, Psyche reached a new milestone for distance from Earth – 390 million km. That is equivalent to Earth and Mars’ farthest distance from each other. During this window, operators managed to maintain a 6.25 megabits per second download link. While that’s a few orders of magnitude slower than the maximum data rate it reached the closer distance, it is still orders of magnitude above the same data rate of a radio frequency connection with the same power output.
As part of this Phase I test, what else would NASA send from its spacecraft but a cat video—in this case, an ultra-high-definition video of a cat named Taters chasing a red laser pointer for 15 seconds straight. As a proof of concept for a high-speed communication line, most of the internet would agree that this is a good use of bandwidth.
Ultimately, the latest successful connection in June was the end of the first Phase of testing for the system. The project team unequivocally proved that, as expected, communication data-rate reduction was proportional to the inverse square of the distance between Earth and Psyche. In other words, the data rate decreases even faster as the distance increases between the spacecraft and the base station.
Taters probably didn’t understand how important it was that he catch the laser – but he was trying his best anyway.A second phase of the experiment will pick up in November when the laser transceiver is turned back on again. At that point, it will prove the system can operate for more than a year, and eventually, the system will be brought up into full operational mode later in 2024. Psyche is scheduled to arrive at its target asteroid in 2029, so the team will have plenty of time to prep their system for operation before that time. There is also a backup radio frequency communication system on Psyche in case the laser system fails – and even that is still faster than lanterns and shutters.
Learn More:
NASA JPL – NASA’s Laser Comms Demo Makes Deep Space Record, Completes First Phase
UT – Psyche Gives Us Its First Images of Space
UT – We’re Entering a New Age When Spacecraft Communicate With Lasers
UT – NASA’s Psyche Mission is off to Asteroid Psyche
Lead Image:
NASA’s Psyche spacecraft is depicted receiving a laser signal from the Deep Space Optical Communications uplink ground station at JPL’s Table Mountain Facility in this artist’s concept. The DSOC experiment consists of an uplink and downlink station, plus a flight laser transceiver flying with Psyche. Credit: NASA/JPL-Caltech
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The massive South Pole-Aitken (SPA) basin is one of the Moon’s dominant features, though it’s not visible from Earth. It’s on the lunar far side, and only visible to spacecraft. It’s one of the largest impact features in the Solar System, and there are many outstanding questions about it. What type of impactor created it? Where did the ejected material end up? Is it feasible or worthwhile to explore it?
But the biggest question could be: how old is it?
The SPA basin is about 2500 km (1600 mi) in diameter and between 6.2 and 8.2 km (3.9–5.1 mi) deep. Research shows that it’s the Moon’s oldest impact basin and likely formed between 4.2 and 4.3 billion years ago. That places it in the most intense period of bombardment in the inner Solar System. But there’s debate about the accuracy of that date. A more precise measurement would help scientists understand the history of the Solar System and the periods of bombardment that helped shape it.
Researchers at the University of Manchester and other institutions tackled the problem of the SPA’s age. Their results are in a paper in Nature Astronomy titled “Evidence of a 4.33 billion year age for the Moon’s South Pole–Aitken basin.” The lead author is Professor Katherine Joy from The University of Manchester.
“The implications of our findings reach far beyond the Moon. We know that the Earth and the Moon likely experienced similar impacts during their early history, but rock records from the Earth have been lost.”
Co-author Dr. Romain Tartese, University of ManchesterWhatever struck the Moon, the impact was catastrophic. Some estimates suggest the impactor was 200 km in diameter, far more massive than the 10 km Chicxulub impactor that ended the dinosaurs. This massive, energetic impact represents a key event in the inner Solar System’s history.
“Determining the timing of this catastrophic event is key to understanding the onset of the lunar basin-forming epoch, with implications for understanding the impact bombardment history of the inner Solar System,” the researchers write. “Despite this, the formation age of the SPA basin remains poorly constrained.”
The inner Solar System bodies have been pummelled by comets and asteroids. On Earth, the evidence of these impacts is mostly wiped away by billions of years of plate tectonics and weathering. There’s only faint evidence of most impacts. The Vredevort impact crater in South Africa was created by a massive impactor about two billion years ago. It’s so eroded that scientists aren’t certain how large the original impact structure was.
Since Earth’s impact features are incomplete, scientists study the lunar surface to understand both the Earth and the Moon’s bombardment history. Fortunately, some evidence from the lunar surface has made it to Earth in the form of samples collected by landers. Some serendipitous evidence also comes in the form of meteorites.
Study co-author Dr. Romain Tartese, Senior Lecturer at The University of Manchester, said, “The implications of our findings reach far beyond the Moon. We know that the Earth and the Moon likely experienced similar impacts during their early history, but rock records from the Earth have been lost. We can use what we have learnt about the Moon to provide us with clues about the conditions on Earth during the same period of time.”
When a large impactor travelling quickly strikes a rocky planet or moon, it releases a lot of energy. The impact can spread debris around the surface and even launch some into space. Scientists have studied multiple meteorites that came from lunar and Mars impacts, and they’ve learned a lot by studying them. In fact, there are so many of them that they’ve been able to categorize many meteorites according to their asteroidal parent bodies.
At least one piece of debris from the impact reached Earth: a lunar meteorite named Northwest Africa 2995.
Over the years, different researchers have examined NWA 2995. By comparing it to Apollo samples, they’ve found that it has the same oxygen isotope ratios, which points to a shared lunar origin. The meteorite’s minerals and texture are also very similar to crustal rocks from the lunar highlands.
The researchers write that the meteorite is in “good agreement with lithologies exposed within the southern region of the SPA basin.”
NWA 2995 was found in Algeria in 2005 and it hasn’t been on Earth for long. It’s only been here for a few thousand years, and by analyzing the concentration of certain cosmogenic nuclides, which are atoms produced by exposure to cosmic rays, scientists have determined that the rock has only been travelling in space for about 22 million years. So, though it was initially created in an ancient impact, it was only launched into space much later by a subsequent impact. MWA 2995 is relatively unchanged and can provide insights into the early Solar System.
NWA 2995 is what scientists call regolith breccia. Regolith is the layer of unconsolidated rocky material that covers bedrock. Breccia is a rock formed from angular fragments of rocks and minerals that are cemented together by fine-grained material. According to the authors, NWA 2995 represents an “ancient fused lunar soil, made up of many different rock and mineral components. ”
The researchers examined NWA 2995 to constrain the age of the SPA basin. They used radiometric dating on a range of mineral and rock components of the meteorite to find NWA 2995’s age.
This image from the research shows a section of NWA 2995 in four different views. a is an optical scan, b is a back-scattered electron image from an electron microscope, c is a cathodoluminescence image that highlights certain minerals, and d is a composite false colour element map. The colours represent silica (blue), aluminum (white), magnesium (green), iron (red), titanium (pink), potassium (cyan) and calcium (yellow). Image Credit: Joy et al. 2024.The researchers also compared NWA 2995 with orbital data from NASA’s Lunar Prospector, which used a low polar orbit to map the Moon’s surface composition. They created a map showing the probabilities that the meteorite originated in different regions on the Moon.
This figure from the research shows the probability that NWA 2995 came from different locations on the lunar surface. Image Credit: Joy et al. 2024.They found that the meteorite most likely came from one of two locations, both inside the SPA. The nearby Cabannes craters are all the right size to eject a rock like NWA 2995.
c is from a unified geological map of the Moon, and d shows stratigraphic units by age. Image Credit: Joy et al. 2024.The researchers analyzed the ages of uranium and lead in NWA 2995. Overall, the results indicate that the SPA basin formed about 4.32–4.33 billion years ago. That means that it formed about 120 million years before the main cluster of other lunar basins like the Serenitatis, Nectaris, and Crisium basins.
This image shows thorium concentrations on the Moon. Thorium is used in conjunction with uranium in radiometric dating to help determine the Moon’s chronology. Radiometric data suggests that NWA 2995 came from the South Pole-Aitken Basin. Image Credit: Joy et al. 2024.Dr Joshua Snape, Royal Society University Research Fellow at The University of Manchester, is one of the co-authors of the new research. “Over many years, scientists across the globe have been studying rocks collected during the Apollo, Luna, and Chang’e 5 missions, as well as lunar meteorites, and have built up a picture of when these impact events occurred,” Snape said.
“For several decades there has been general agreement that the most intense period of impact bombardment was concentrated between 4.2-3.8 billion years ago – in the first half a billion years of the Moon’s history,” said Snape. “But now, constraining the age of the South-Pole Aitken basin to 120 million years earlier weakens the argument for this narrow period of impact bombardment on the Moon and instead indicates there was a more gradual process of impacts over a longer period.”
These results will only grow stronger when future missions collect more samples from the area. “The proposed ancient 4.32 billion year old age of the South Pole-Aiken basin now needs to be tested by sample return missions collecting rocks from known localities within the crater itself,” said lead author Joy.
“Our proposed formation age for SPA will require confirmation from future radiometric dating of samples collected from the south of the Apollo basin area by the Chang’e–6 mission or from future proposed missions such as the Endurance-A rover concept that aims to collect 100?kg of samples from across the SPA basin floor,” the authors write in their conclusion.
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There’s not much new this week, and certainly nothing to inspire me to comment on science, current events, and so on. So it’s time to go back fifty years and compare the Billboard Top Ten Songs from then with the current ones. It turns out that the comparison isn’t as dire as it has been the last few times.
This may be for two reasons. First, rock had already reached its apogee before 1974, and while there are a couple of classics on the 1974 list, and certainly some great musicians, the list in general is not inspiring.
Second, it seems to me that pop music is getting infused with a soupçon of country music, and, given how bad recent pop music has been, this can only improve it.
First, the list from this week in 1974. I’ve put a link to the performance of each song.
The best songs on this list include #1 (the Spinners were underrated: “I’ll Be Around” is one of the great soul songs), and the addition of Dionne Warwick makes for a creditable tune. The Stevie Wonder song is okay, but not close to his greatest efforts (viz. “Isn’t she Lovely?” or “For Once in my Life“, etc.). I have little use for Bachman Turner Overdrive, but “Jazzman: is an excellent effort by Carole King. The Elton John song is an 8; I can dance to it. Bad Company’s song rates a 5 out of 10, and it’s downhill from there, save the classic “Sweet Home Alabama”. Ergo, I’d rate #1, #4, and #8 as music that will last. We shall forget about Tony Orlando, Mac Davis, and the Osmonds.
Here is the Billboard Top 10 from fifty years ago: October 21, 1974:
1.) “Then Came You” Dionne Warwicke and the Spinners
2.) “You Haven’t Done Nothing” Stevie Wonder
3.) “You Ain’t Seen Nothing Yet/Free Wheelin'” Bachman Turner Overdrive
4.) “Jazzman” Carole King
5.) “The Bitch is Back” Elton John
6.) “Can’t Get Enough” Bad Company
7.) “Steppin’ Out/Gonna Boogie Tonight” Tony Orlando and Dawn
8.) “Sweet Home Alabama” Lynyrd Skynyrd
9.) “Stop and Smell the Roses” Mac Davis
10.) “Love Me for a Reason” The Osmonds
And the latest Billboard Top 10 from October 19, 2024.
The music on the list below is surprisingly good given that it’s from today. I’m not a fan of “A Bar Song” as it’s too rap-py—but note the country tinge to it! My favorite on this list is Billie Eilish’s song (#2), which is quite lovely. #3 is largely a country/pop hybrid. It’s okay, but the melody and words are rather trite. We shall leave aside the talentless Sabrina Carpenter, which eliminates three songs off this list. The Bruno Mars/Lady Gaga duet has the trappings of country music (cowboy hats and boots, and big hair on Lady Gaga), but it’s just okay: neither catchy or memorable. Chappell Roan appears to be a phenom these days, but I wasn’t impressed with this effort, which in the end is a standard love song, and the melody is trite. Skipping over Carpenter to Swims, we find a song that’s beginning to sound of a piece with much of modern music, but it’s okay (note the country intonations). Skipping Carpenter for the last time (yes, I listened to all the songs), we finish with Benson Boone, performing a countrified pop song, but again the tune is boring and the lyrics uncompelling.
1.) “A Bar Song” Tipsy
2.) “Birds of a Feather” Billie Eilish
3.) “I Had Some Help” Post Malone featuring Morgan Wallen
4.) “Espresso” Sabrina Carpenter
5.) “Die With a Smile” Lady Gaga with Bruno Mars
6.) “Good Luck, Babe!” Chappell Roan
7.) “Taste” Sabrina Carpenter
8.) “Lose Control” Teddy Swims
9.) “Please Please Please” Sabrina Carpenter
10.) “Beautiful Things” Benson Boone
All in all, the lists are pretty much tied, but 1974 wins (you knew it would!) because it has a couple of classics. The latest list, in my view, is redeemed by Billie Eilish‘s song, and I should sample more of her music. I see she’s only 22 and her full name is Billie Eilish Pirate Baird O’Connell. (Note that Wonder’s “For Once in My Life” was recorded when he was just 18.)
Here’s “Birds of a Feather” by Billie Eilish, co-written with her brother, Finneas O’Connell