Category: 7. Science

Octopuses have many amazing abilities and characteristics; they have huge brains and can solve puzzles; their ink can disguise them and disorient attackers; and their ancestors are thought to be about 330 million years old. There are about 500 million neurons in octopus arms, and the suction cups on those arms may hold as many as 10,000 sensory cells each. Scientists have now shown that octopus arms can move over the seafloor to taste the stuff that’s there, and determine whether it is safe to eat. The arms can sense the biochemicals in microbial communities, and figure out whether they are harmless or dangerous. The findings have been reported in Cell.

Microbes surround and coat many things in our world, even underwater. Marine microbiomes are dynamic, changing in response to environmental conditions constantly. They release different chemicals that reflect their surroundings, and the octopus can sense some of them, like those that grow on eggs or crabs. This enables them to understand their habitat, explained first study author Rebecka Sepela, a postdoctoral researcher at Harvard University.

This work aimed to decipher some of the sensory capabilities of octopuses, which can taste by touching. The researchers observed saltwater tanks containing California two-spot octopuses, which are enclosed by a lid that is fastened on with velcro and weighted down by bricks. “We’ve had them open their tanks and get out,” noted senior study author Nicholas Bellono, a Harvard Professor.

When fiddler crab shells or octopus eggs were placed in the tanks, there were strong reactions from the octopuses. They are able to eat blindly, foraging in the dark by relying on the sensory information that comes in through their suction cups and arms. The octopuses quickly ate live fiddler crabs, which they typically enjoy, but opted not to consume decaying crabs. Octopus moms also cared for healthy eggs, while rejecting dead or infertile ones.

The stuff that was put in the tanks, whether it was good or bad crabs or eggs, hosted significantly different microbiomes. Live crabs didn’t carry many microbes, while decaying crabs had tons of different kinds of bacteria. Rejected eggs were found to host spirillum-shaped bacteria, which were absent from healthy eggs.

A genetic analysis revealed even more about the microbiomes, and the molecules they emit. The investigators identified these compounds and tested their impact on octopus receptors.

This work showed that some microbial compounds elicited a response from certain octopus receptors. 

When one of the compounds that is a product of the spirillum-shaped bacteria was put onto a fake egg and placed in the octopus tank, it was briefly groomed, then rejected by the mother octopus.

This study also opens up new questions about how widespread this type of interaction might be.

“There is a lot more to be explored,” said Bellono. “Microbes are present on almost every surface. We had a nice system to look at this in the octopus, but that doesn’t mean it’s not happening across life.”

Sources: Harvard University, Cell

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Early risers are in for a celestial treat on July 5, when Venus appears as a bright ‘morning star’ alongside the magnificent Pleiades open star cluster in the eastern sky just before dawn.

Stargazers in the U.S. can see Venus rising around 3 a.m. local time, with the Pleiades star cluster visible as a smudge of light under dark sky conditions less than 7 degrees to Venus’ upper left. To estimate that distance, hold a clenched fist at arm’s length; it spans roughly 10 degrees of sky.

The cosmic duo will be visible for around two and a half hours before the glare of the rising sun hides the Pleiades from view. While the cluster is known to contain a multitude of blue-white stars, our naked-eye view of the Pleiades from Earth is largely dominated by its seven brightest members : Alcyone, Asterope, Celaeno, Electra, Taygete, Merope and Maia. The light from these stars is best viewed away from city lights and becomes easier to detect when the star cluster is in the periphery of your vision, where the cells that excel at night vision are at their densest.

The seven brightest stars can be picked out using a pair of 10×50 binoculars, while a telescope with an aperture of 4 inches or greater will reveal more of the cluster’s thousand-strong stellar population.

Venus, meanwhile, is stunning to view with the naked eye alone, shining at magnitude -3.9. However, pointing a telescope with an aperture of 2.4 inches or greater with a magnification of 50x or more will allow you to pick out its moon-like phases, according to telescope-maker Celestron.

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But wait, there’s more! The ice giant Uranus is also present in the sky on July 5, positioned almost directly between Venus and the Pleiades. However, its relatively dim magnitude of +5.8 makes it incredibly challenging to spot with the naked eye. Remember, magnitude is the system astronomers use to keep track of how bright an object appears in our night sky. The lower the number is, the brighter the object. The human eye is capable of spotting objects brighter than magnitude +6.5 in dark sky conditions.

To see Uranus’ tiny aqua disk you’ll need a telescope with an 8-inch aperture. However, even then it will appear as little more than a blue point of light hanging against the starfield beyond.

Editor’s Note: If you capture a picture of Venus with the Pleiades and want to share it with Space.com’s readers, then please send your photo(s), comments, name and location to spacephotos@space.com.

Long believed to be a single, globally distributed species drifting freely across the open ocean, the bluebottle – also known as the Portuguese man o’ war – has been revealed to be a group of at least four distinct species, each with its own unique morphology, genetics, and distribution.

Uncovered by an international research team led by scientists at Yale University, the University of New South Wales, and Griffith University, the genetic discovery is being heralded as something of a revelation to the marine biology community.

It was made when researchers began sequencing the genomes of 151 Physalia specimens from around the world. Now published in the journal Current Biology it found “strong evidence of reproductive isolation” among five genetic lineages.

“The genetic data clearly show they’re not only different, they’re not even interbreeding despite overlapping ranges,” said Professor Kylie Pitt, a professor at Griffiths University. 

The bluebottle is uniquely suited to long-distance travel, using its gas-filled float and muscular crest to catch the wind and sail the sea surface. Using an integrative approach, the team matched genomic lineages with four distinct physical forms identified from thousands of citizen-science images submitted to iNaturalist.org.

Interestingly, this isn’t the first time the suggestion that the bluebottle was in fact four morphological separate species has been made. The idea was originally proposed in the 18th century and again in the 19th century but dismissed each time.

Using today’s advances in science, however, the suggestions have indeed been verified by modern genomic evidence.

A NASA astronaut has captured an electrifying image of Earth from space, featuring a gigantic, jellyfish-shaped “sprite” of red lightning shooting upwards above a thunderstorm in North America. The rare phenomenon is still poorly understood, despite being studied for more than 30 years.

Nichole Ayers, the pilot of SpaceX’s Crew-10 mission and member of International Space Station (ISS) expeditions 72 and 73, snapped the striking photo on Thursday (July 3) as the space station passed above a large thunderstorm hanging over parts of Mexico and the southern U.S., including California and Texas.

For years, scientists have suspected that stars can meet their doom by a one-two punch of back-to-back explosions — but they’ve never seen visual evidence of this happening.

That just changed. Astronomers using the Very Large Telescope in Chile have taken the first-ever image of a star that died in a stellar “double-detonation,” leaving behind a spectacular supernova remnant.

Their findings, published as a new study in the journal Nature Astronomy, deepen our understanding of the stellar evolution of burned-out stars called white dwarfs.

“The explosions of white dwarfs play a crucial role in astronomy,” lead author Priyam Das, a researcher at the University of New South Wales Canberra, Australia, said in a statement about the work. “Yet, despite their importance, the long-standing puzzle of the exact mechanism triggering their explosion remains unsolved.”

Once an exceptionally massive star — one at least several times heavier than the Sun — burns through all its fuel, it collapses under its own gravity in a powerful explosion known as a supernova. 

That’s just one way supernovas can happen, though, and not all of them end the same. Some result in the star being completely obliterated, but others, if the star is heavy enough, can produce a super dense core called a neutron star, or even a black hole.

The scene imaged by the VLT is the work of what’s called a Type Ia supernova, produced by a low-mass star that exhausted all its fuel and left behind a remnant called a white dwarf. These objects are more compact and far denser than their original stars, endowing them with a wicked gravitational pull.

In binary systems, this powerful gravity can lead to the white dwarf stripping matter off its stellar companion if their orbits are close enough. When enough of this stolen material accumulates on the surface of the white dwarf, reaching a point known as critical mass, it kickstarts a single but incredibly destructive thermonuclear explosion that wipes out both stars.

That’s the typical understanding. More recent research, though, has found evidence that some white dwarfs are battered by two explosions, not one, prior to winking out. In this scenario, astronomers believe that a white dwarf is swimming in a cloud of siphoned helium. This unstable helium cloud is the first to explode, precipitating a second blast in the core of the star. And bam: you have a two-fer supernova.

Critically, this type of supernova occurs before the white dwarf reaches critical mass. Astronomers predicted that this double-detonation would produce a unique, visual signature in the form of two separate shells of calcium — and the new image bears this out. If you look closely, you can see that the calcium, depicted in blue, is indeed in a two-shell arrangement.

This is a “clear indication that white dwarfs can explode well before they reach the famous Chandrasekhar mass limit, and that the ‘double-detonation’ mechanism does indeed occur in nature,” said coauthor Ivo Seitenzahl, who conducted the observations while at the Heidelberg Institute for Theoretical Studies in Germany, in the statement.

The work is invaluable for another reason. Type Ia explosions are considered “standard candles” that astronomers use as a measuring stick in the cosmos, because they shine at a consistent luminosity. Now we understand a little more about why that’s the case.

“Revealing the inner workings of such a spectacular cosmic explosion is incredibly rewarding,” Das said.

More on stars: Scientists Working to Decode Signal From Earliest Years of Universe

Sotheby’s will auction off the largest known Martian meteorite on Earth later this month—and the iconic auction house is accepting Bitcoin for a piece of the red planet.

The meteorite, known as Northwest Africa 16788 or NWA 16788, was discovered in Niger’s Agadez region in 2023 and weighs 54 pounds. It’s expected to fetch between $2 million and $4 million at Sotheby’s Natural History sale on July 16.

“Sotheby’s has accepted cryptocurrency for select sales since 2021,” Cassandra Hatton, Vice Chairman of Science and Natural History, told Decrypt. “Given the global interest in rare meteorites and the tech-savvy audience they attract, it made sense to offer that option here.”

According to Sotheby’s, NWA 16788 is the most valuable (and expensive) Martian specimen ever offered at auction. In February 2021, Christie’s sold a much smaller piece of a meteorite for $40,000, noting at the time that “specimens of Mars are among the most exotic substances on Earth with less than 250 kg (550 lbs) known to exist.”

As with previous Sotheby’s auctions, bids can be made in Bitcoin, Ethereum, and USDC.

“If you know the crypto world, it’s a lot of work to ensure that systems are set up, that everything is compliant,” Hatton said, noting that Sotheby’s utilizes Coinbase and Bitpay for its crypto auctions. “Sotheby’s has been doing the really deep work of ensuring that everything is done to the highest standards.”

When asked about the hefty price tag, Hatton explained that, unlike fine art, estimating the value of meteorites and other exotic pieces is a more complex and less predictable process. Last summer, a skeleton of a Stegosaurus, nicknamed Apex, estimated to be worth $4 million to $6 million, was sold for $44 million.

“It’s easy to estimate a Picasso or Warhol because we’ve sold many. But in my world, where everything is unique and rarely sold, it’s a different exercise,” she said. “The estimates show possibility, not hard market data.”

Also, unlike art, meteorites, Hatton added, are generally priced per weight.

“I’ve had people build spreadsheets analyzing Martian, lunar, and other meteorites per gram—and the data lines up,” she said. “There’s a natural price-per-gram structure in the market.”

When asked about the current owner, Hatton said that NWA 16788, consigned by a private owner for Sotheby’s annual Geek Week auctions, has been authenticated by the Meteoritical Society.

Accepting crypto payments in the auction of NWA 16788 is the latest in Sotheby’s outreach and attempt to appeal to the crypto community. When asked why Sotheby’s continues to accept cryptocurrency, Hatton pointed to client demand and past success.

In 2023, Sotheby’s auctioned a collection of Bitcoin Ordinals called BitcoinShrooms. More recently, Sotheby’s sold Bored Ape Yacht Club NFTs once owned by the defunct Three Arrows Capital, and in January, it offered NBA Top Shot NFTs as part of a broader NBA memorabilia sale.

“We’ve had major, high-value lots paid for with cryptocurrency. The goal is to accommodate the widest group of potential bidders,” she explained. “Many of my clients work in crypto, earn from it, or hold it, and they’ve told me, ‘You should be accepting cryptocurrency for everything.’ So I’m responding to that demand.”

Edited by Andrew Hayward