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Can we spot every incoming asteroid before they hit Earth?

New Scientist Feed - Thu, 09/05/2024 - 9:44am
News of the asteroid 2024 RW1 impacting near the Philippines may have come as a shock this week, but space agencies and astronomers around the world are keeping an eye out to protect us
Categories: Science

U.S. charges six Hamas leaders with terrorism and conspiracy, and a Gazan peace plan that people won’t like

Why Evolution is True Feed - Thu, 09/05/2024 - 9:30am

As the Washington Post and other sources report, the U.S. has charged six Hamas officials with criminal counts of terrorism connected with the October 7 attack on Israel:

U.S. officials unsealed charges Tuesday against senior Hamas leaders, accusing them of conspiring to provide material support to a terrorist organization, conspiring to murder Americans and conspiring to use weapons of mass destruction.

The criminal complaint against Hamas leader Yehiya Sinwar and others was made public as U.S. diplomats are preparing to present Israel and Hamas with a final hostage-release and cease-fire proposal, potentially as soon as this week.

Bizarrely, at least three of these officials are dead.  Another, Yahya Sinwar, the military head of Hamas, is scuttling around the tunnels of Gaza and is, at present, beyond reach. But at least one person, the political head of Hamas, and who lives in Doha, Qatar, is within the reach of U.S. courts. Here’s the list of those indicted, taken from the Times of Israel.Notes are mine except for those in quotes.

Yahya Sinwar, the military head of Hamas. Scuttling around the tunnels under Gaza. Sinwar served 22 years in an Israeli prison for terrorism until he was released in a prisoner swap and went on to plan the October 7 massacre (remember that when you start approving of such swaps to get the hostages back). One of the ironic things about Sinwar is that Israeli doctors saved his life by removing a malignant brain tumor when he was in prison, and he not only didn’t give up his hatred of Israel and Jews, but the nephew of the main doctor who saved him was killed in the October 7 massacre.

Ismail Haniyeh, former political head of Hamas who lived in Qatar but was assassinated (almost surely by Israel) by a bomb planted in his room during a visit to Tehran last July.

Marwan Issa, “the once-deputy leader of Hamas’s armed wing in Gaza, who was killed by Israel in March.”

Khaled Mashaal, “a Haniyeh deputy based in Doha and a former [political] leader of the group.”  Now that Haniyeh is dead, Sinwar has taken over political and military control of Hamas, but Mashaal is playing a very important role in the group, not to mention all the money that Hamas has in the hands of its members in Qatar.  Mashaal recently called for a return of Palestinians to conducting suicide attacks on Israelis.

Muhammad Deif, the longtime Hamas military wing chief, who Israel killed in July.  Wikipedia says it’s not sure he’s dead, though was crippled after several assassination attempts, but the IDF says it’s sure he’s dead, and on matters like this I trust the IDF more than Wikipedia.

Ali Baraka, “the Beirut-based head of Hamas’s external relations.”

Now I don’t know what the point of indicting three dead people is; if anything, it’s a purely symbolic gesture. The most likely explanation is that the indictment was issued in February and was just unsealed, and the three dead thugs were still alive in February.

But anybody indicted who is still alive and resides in Qatar can be subject to extradition, and that means Mashaal. The U.S. should ask for his extradition immediately, though given who’s in charge of America now, I doubt this will happen.

Which brings us to the Gaza “peace plan”. The U.S. is saying that it’s about to float a “take-it-or-leave-it” peace deal for Gaza, and although the details are hazy, it seems to involve a time-limited  ceasefire in hopes of a permanent one, a swap of some of the living and dead hostages (not all at once) for a pile of live Palestinians imprisoned in Israel, and nothing about the surrender of Hamas.

This is a plan that will fail, and it’s also short-sighted.  It will leave Hamas in power and will not end anti-Israel terrorism. If you want a good explication of its problems, read Bret Stephens’s column in the NYT yesterday, “A hostage deal is a poison pill for Israel” (link is archived).

Like me, Stephens is no fan of Netanyahu, but he thinks that the PM is right in his strategy about the war (read the column).  Stephens has always been the most sensible NYT op-ed writer about the war: far more cogent than, for example, Tom “I Know Nothing” Friedman. Stephens’s column, which once again I recommend, ends this way:

There are bright people who say that what Israel ought to do now is cut a deal, recover its hostages, take a breather and start preparing for the next war, probably in Lebanon. Israelis should remember that wars will be worse, and come more often, to those who fail to win them.

Here’s my own recommendations for ending the war. They may not work, but they seem sensible, and most of them are based on Malgorzata’s ideas:

a.) Call for the extradition of Mashaal now.

b.) Qatar should arrest all Hamas members finding refuge in that country and freeze their bank accounts (there are billions of dollars there, most of the money in the hands of Hamas). That money should be used to rebuild Gaza.

c.) The first two points should be done under a U.S. threat: do these things or face the removal of the U.S. military presence in Qatar (its base is shared with the RAF, so the UK would have to agree as well). We don’t need the base that badly (we have other bases in other Middle East nations), but Qatar desperately needs it, for without it, oil-rich Qatar will be taken over by countries like the UAE, Kuwait, and Saudi Arabia.(Qatar has almost no military of its own.) This would be a threat with real teeth. And the U.S. should be ready to follow through with it, as with all meaningful threats.

d.) Instead of confecting unworkable and, frankly, stupid peace plans, the U.S. should simply call for the unconditional surrender of Hamas and the instantaneous release of all the hostages.  Hamas will not surrender, of course, but anybody who values their life (and yes, there’s a rub there) must realize that Israel under Netanyahu has vowed to destroy the military capabilities of Hamas—and will do so. The Biden Administration (and Harris, should she win) should be giving nothing to terrorists like Hamas.

The moral right in this conflict lies with Israel, not with Hamas, and the U.S. should be calling for the terrorists to give up, end the war, and release the hostages. Remember again that the “take-it-or-leave-it” deal will not work and gives plenty of stuff to Hamas.

Needless to say, the U.S. should not be cutting aid to Israel, even though some European countries are.  Such cuts are again ludicrous and short-sighted given Israel’s care to kill as few Gazan civilians as possible combined with Hamas’s desire to get as many non-combatant Gazan civilians killed as possible to excite the world’s opprobrium against Israel. Right now, Europe, and to some extent the U.S., is doing pretty much what Hamas wants.

e.) What about the day after?  A two-state solution is not in the offing right now; that much is clear and amounts to rewarding Hamas for the October 7 attack. I suspect that a military occupation of Gaza will have to occur for some time, as happened in Germany and Japan after World War II.  At the same time, Israel and its allies should be grooming reasonable and peaceful Palestinians to take over running Gaza. (I’m not discussing the West Bank here.)

Yes, yes, I know all the weaknesses of this plan: Hamas won’t give up, the U.S. won’t threaten to dismantle a military base, no credible Palestinians who don’t want to destroy Israel will be found, etc. etc. If you want to pick at the plan, at least do something constructive and propose a better one, and one that doesn’t lead to Israel losing the war and facing many more October-7-like episodes.

But one thing is certain, something Bret Stephens encapsulates in his last sentence: all the “cease fire” proposals floating around now are guaranteed to leave Hamas in power, and thus to keep a constant threat of terrorism against Israel. And that means that peace will never be attained.

Categories: Science

Achieving a supercapacitor through the 'molecular coating' approach

Matter and energy from Science Daily Feed - Thu, 09/05/2024 - 9:10am
A capacitor is like a high-speed battery that can quickly store and release energy. What happens when it becomes 'super?' Researchers have potential solutions to improve energy-efficiency.
Categories: Science

Faster detection of dangerous infections

Matter and energy from Science Daily Feed - Thu, 09/05/2024 - 9:10am
In an infection, there are tens of thousands of peptides that provide a wealth of information about which bacteria have caused the infection and how severe it is. A research team combined clinical questions with mathematical methods to systematically analyze these peptides. This has the potential to transform the diagnosis and treatment of infections in the future.
Categories: Science

Researchers discover a space oddity -- an exoplanet moving in mysterious ways

Space and time from Science Daily Feed - Thu, 09/05/2024 - 9:09am
A research team has discovered a small planet that displays peculiar orbital motion. The shimmying planet, located 455 light-years from Earth, shows that planetary systems can be considerably more complex than researchers have previously thought.
Categories: Science

Probing the depths of complex electron shells

Matter and energy from Science Daily Feed - Thu, 09/05/2024 - 9:09am
The heavy metal uranium is, besides its radioactive reputation, known for its intricate chemistry and diverse bonding behaviors. Scientists utilized synchrotron light to explore the unique properties of low-valent uranium compounds.
Categories: Science

Starting a fluorescent biosensor revolution

Matter and energy from Science Daily Feed - Thu, 09/05/2024 - 9:08am
A major step forward toward biosensor devices that can provide fast, high-contrast detection of biomarkers in almost any environment are 'binding-activated fluorescent biosensors.' Now, a research collaboration has developed a synthetic biology platform that streamlines their up-until-now tedious and expensive discovery, as well as their molecular evolution and cost-effective manufacturing, opening a plethora of new biomedical and environmental opportunities.
Categories: Science

Rejecting standard cancer treatment like Elle Macpherson is a big risk

New Scientist Feed - Thu, 09/05/2024 - 8:50am
People with cancer may have understandable reasons to follow Australian supermodel Elle Macpherson in declining chemotherapy, but the odds aren’t in their favour, warns Elle Hunt
Categories: Science

The Atlantic has been suspiciously quiet this hurricane season

New Scientist Feed - Thu, 09/05/2024 - 8:28am
The forecasts predicted an extreme storm season in the Atlantic, but so far there have only been three named hurricanes – so where are all the storms?
Categories: Science

Kruger: Day 5 (and a farewell to the bush)

Why Evolution is True Feed - Thu, 09/05/2024 - 7:15am

This post documents what we saw on our last day in Kruger, the day we had to leave and repair back to Hoedspruit.

First, you might like to see our accommodations at the Satara Rest Camp, which were lovely and inexpensive. Below is my own personal hut with a high thatched roof (thatching is quite a skill, and roofs have to be re-thatched every decade or two.

A view from the inside. I had two beds, a nice bathroom, and a fridge outside with a latch to keep the baboons out. Not to mention air-conditioning, which I didn’t need as it wasn’t hot.

My two beds:

And a view of the thatched roof seen while lying on one of the beds. As you can see from the first picture, the roof was high.

We were near the remains of the buffalo killed by lions, so we dropped by again. One of the lions was still around. Have a look: this is a male with its normal “tawny” color:

And when our guide Isaac told us there were white lions in the park (leucistic ones, not albinos), nothing would do for me except to see them. Given that there are only a few, the chances of that were small. However, Isaac had read on his “Kruger guides” restricted chat group that a white lion had been spotted about a mile north of Satara. So he went looking for it. Given his skills as a spotter, if it was anywhere near the roadside, he’d find it.

And he did!

Here’s one; note that it’s not pure white, but a light yellow, and clearly distinct in color from “regular” lions.  There’s one famous white lion in Kruger called “Casper” (undoubtedly after the ghost), but I’m not sure if this is Casper. It is, however, a male:

One would think that the whiteness might confer an adaptive disadvantage on these animals, either driving away regular lions who don’t like their color, or making these white ones visible to prey. But they don’t seem disabled. As Wikipedia notes:

White lions are not albinos. Their white color is called leucism, and is caused by an allele that is found at the same locus as the allele that causes albinism. It is thought, but not proven, that the allele is inherited in an autosomal recessive fashion.  They vary from blonde to near-white. This coloration does not appear to pose a disadvantage to their survival. White lions were considered to have been technically extinct in the wild between 1992 and 2004, when the Global White Lion Protection Trust achieved the first successful reintroduction of white lions to their natural habitat. These prides have continued to hunt and breed successfully in the wild, whilst other occurrences of white lion births have been reported in the greater Kruger region since then.

There’s more information:

In light of the recent decision by South Africa’s Department of Environmental Affairs (DEA) at CITES 2016, to continue to allow the hunting of captive bred lions (“canned hunting”), and the trade in lion bones from captive bred lions, the Global White Lion Protection Trust (WLT) asserts that the survival of lions in the Greater Kruger Park Region is likely to come under threat, and the white lion is the ideal capstone animal to help better protect all lions in the Greater Kruger Park Region.

I like to think this is Casper. But even if it isn’t, it was a great joy for me to see this animal thriving in the wild. Kudos to Isaac for not only making an effort to find it for me, but also to succeed in that effort!

And a “normal” tawny lion for comparison again. Note the dark mane and distinct brown color.

By this time the remains of the buffalo had been picked clean by both nearby lions and, of course, by vultures, seen below on the bones.  I’m not sure whether the spotted hyenas ever got a crack at this carcass:

A rare sight and one of my collection of “animals crossing the road.”  Lion crossing!  The cars, of course, are lined up to see the sight, which attests to how comfortable these lions are with humans—at least when they’re in cans.

The lion who crossed the road then found a comfortable perch on the other side, explaining “why did the lion cross the road?”:

Eventually we stopped at the Olifants Rest Camp to have breakfast. With a lovely view overlooking the Olifants River (a tributary of the Limpopo River), it has bungalows and would be a delightful place to stay, especially in the rainy summer season when the river must attract lots of wildlife. But if you want to stay there, reserve a year in advance.

It was blowing hard that day, and cold as well, but this brave dude was out there re-thatching a roof with no apparent protection from falling off:

And I got the breakfast I had dreamed of: one that had fried eggs and pap: the African equivalent of grits and eggs.  It was topped with a spicy tomato-y sauce generously larded with crispy fried cubes of pork. It was one of the best breakfasts I’ve ever had, and filled me up so much I couldn’t eat for the rest of the day:

On my way to the facilities, I took a selfie in the mirror:

This view of a thunder of hippos (yes, that’s one proper collective noun for a group of them) was probably taken from the Olipants rest camp, but I can’t remember.

We later came upon a dazzle of zebras (again, a proper collective noun).  I waited patiently with my camera focused on these three until I managed to get a shot of them all looking in my direction. What gorgeous animals!

A Red -crested korhaan (Lophotis ruficrista). I remembered this as a “Jewish bird” by thinking that its real name was the Red-crested Cohen.” It has a lovely pattern as described in Wikipedia:

The red-crested korhaan grows up to 50 cm (1.6 ft) in length with a maximal weight of 680 g (1.5 lb).  The feathering of the wings folded on the back is marked by V-formed patterns of a light cream color with some white at the sides. Breast feathers are black. Legs are pale yellow and feet gray.

Click the picture to enlarge it:

A herd of impala, this one apparently heavy on males (females don’t have horns):

. . . and a male impala crossing the road, probably to rejoin his herd.

You’ll know this species by now if you’ve been following my narrative. Look at the butt for confirmation:

This elephant has had a long drink of water from a cement pool, and the warthog was waiting patiently nearby for its turn to drink. But we waited and waited, and the elephant wasn’t sated. (They can take in 100 liters of water at one time.) So we left, hoping the warthog got a drink.

A journey of giraffe. That’s what you call a group of giraffes that is moving, but a group of stationary giraffes is called “a tower of giraffe”. These are appropriate terms.

And at least we reach the end of our journey in Kruger at the Orpen Gate. There are actually two exits, and at one of them you’re obliged to show your receipts showing you’ve actually paid the conservation fee for each day you’ve stayed.  When I took a photo after the first gate, the gatekeeper woman posted for me:

How sad to leave!

And the second gate, when we once again left the bush and entered “civilization”:

Will I go back again? I’d love to see the park when it’s green in summer, though it also rains then. But, as Stevie Nicks said, “I’m getting older, too.”  Who knows?

If you ever visit Kruger, you should definitely engage Isaac as your guide

Many thanks to Isaac, our guide/driver/spotter, shown below getting a coffee at the exit. Thanks too to Rosemary, who did a pile of work to organize this trip and my visit to Manyelete.

Oh, and I almost forgot.  Ozy went missing for a few days, and I didn’t get to see him after I returned from Kruger and before I came back to Cape Town. I was worried: after all, he’s a Senior Pig.

But he’s back again, reportedly in good nick. Here he is sleeping off his latest foraging bout (photos by Rosemary).

Categories: Science

Spot the leopard!

Why Evolution is True Feed - Thu, 09/05/2024 - 6:15am

If you didn’t see the white lion in the last “spot the” picture, here’s your chance to find an easier cat. (And no wisecracks about how “the leopard is already spotted”)!

Here’s a picture taken from one of the “hides” in Kruger where you can spot wildlife from inside a shed with a viewing slit. Can you spot the leopard? I bet you can.

This, by the way, is the only leopard we saw in Kruger, though I got awesome views of one in Manyelete (see photos from that trip).

Categories: Science

The University of Chicago falls to #43 in FIRE’s free-speech rankings

Why Evolution is True Feed - Thu, 09/05/2024 - 5:15am

I got this tweet from Luana, who noted Chicago’s steep fall from grace in FIRE’s free-speech rankings for 2025. (“The College Pulse” also collaborated in the rankings.)

FIRE’s 2025 Campus Free Speech Rankings are out.

Harvard is once again the worst school on the list.

Columbia and New York University join it in the “abysmal” category.

Penn and Barnard are among the four “very poor” schools. pic.twitter.com/fJ5yenYiF7

— Steve McGuire (@sfmcguire79) September 5, 2024

Click the screenshot to see all 251 rated schools.

Here are the top ten. Note that the University of Chicago, once #1 for a long time and always in the top five, is no longer at the top. In fact, the top school, the University of Virginia, simply gets a “good” rating and a so-so score of 73.4 out of a hundred.

Where, oh where, is my school?  It’s a dismal #43, and rated only “slightly above average.”

The low score appears to reflect a big difference in the campus’s willingness to tolerate liberal vs. conservative speakers, and a high score in the degree of self-censorship that students practice.

This is very sad, for we can no longer even say we’re in the top ten, and Chicago’s reputation for being a bastion of “free speech” has taken a severe hit.

As for the bottom ten, well, Harvard is the worst, but now both NYU and Columbia have joined it with the rare “abysmal” rating:

All I can say is “oy vey!”, and that the administration is going to have to do some fast-stepping, for they used to tout our high ratings and now will have to confect some reasons why the rating system isn’t very good.

Categories: Science

Explaining Different Kinds of Meteor Showers. It’s the Way the Comet Crumbles

Universe Today Feed - Thu, 09/05/2024 - 4:28am

The Universe often puts on a good show for us down here on Earth but one of the best spectacles must be a meteor shower. We see them when particles, usually the remains of comets, fall through our atmosphere and cause the atmosphere to glow. We see them as a fast moving streak of light but a new paper has suggested that the meteor showers we see can explain the sizes of the particles that originally formed the comet from where they came. 

Comets are mostly composed of ice but with a little rock mixed in for good measure. They’ve often been called dirty snowballs to describe this mix of ice and rock. They travel around the Sun in elongated, elliptical orbits which bring them close to the Sun. The intense heat from the Sun causes the ice to instantly turn into a gas in a process known as sublimation which releases the trapped dust. The pressure from the Sun known as the solar wind presses against the gas and dust released from a comet to produce the tail which always points away from the Sun. 

A recent animation of Comet 12P. Image credit: Michael Jaeger.

As the comet travels around the Solar System, it deposits debris along its orbit almost like a trail of celestial breadcrumbs. The debris at this stage is known as meteoroids but, if the Earth travels through it then they create the stunning meteors that we see streak across the sky. The Earth passes through the debris field from a number of comets on a regular, annual basis and this gives rise to the regular meteor showers we see such as he Perseids or Leonids. 

A Geminid meteor outburst from 2020. Image credit and copyright: Jeff Sullivan

A team of 45 researchers have been studying meteor showers and have discovered something rather curious. They have found that not all comets crumble in the same way as they approach the Sun. The team studied 47 young meteor showers by using special low light video cameras all over the world. The cameras measured the path of the meteors enabling the team to work out how high up they were when they first light up and how they then slowed down in the atmosphere. They were also able to measure the composition enabling them to deduce the size of the particles.

In a paper published in the journal Icarus, the team theorised that a comet will simply crumble into the size of the ‘pebbles’ they are made of. This does seem to make complete sense given that the comets form as chunks of dust, rock and ice. More ice will slowly form as the comet orbits out in the dark cold reaches of the Solar System but as it heats on its journey inwards, it will just fall apart again as the ice sublimates. 

The results of the paper showed that longer period comets, such as those originating in the Oort Cloud generally crumble into sizes of particulates indicative of slow and gentle accretion conditions.  The resultant meteoroids have a lower density and tend to only brighten deeper into the Earth’s atmosphere. Comets from the Jupiter-family on the other hand crumble up into smaller, denser meteoroids with 8% more solid material on average.

There are a few meteor showers that originate from asteroids and these too have been studied. The team found that they tend to produce meteor showers with smaller particles that have evidence of aggressive fragmentation during their formation. The team acknowledge there will be exceptions to their findings but it their study has helped to build a more fuller picture of the early stages of the evolution of the Solar System and to the nature of comets that grant us the beauty of meteor showers.

Source : Meteor showers shed light on where comets formed in the early solar system

The post Explaining Different Kinds of Meteor Showers. It’s the Way the Comet Crumbles appeared first on Universe Today.

Categories: Science

Google breakthrough paves way for large-scale quantum computers

New Scientist Feed - Thu, 09/05/2024 - 4:04am
Google has built a quantum computer that makes fewer errors as it is scaled up, and this may pave the way for machines that could solve useful real-world problems for the first time
Categories: Science

Thursday: Hili dialogue

Why Evolution is True Feed - Thu, 09/05/2024 - 3:16am

Meanwhile, in Dobrzyn, Hili has won at hide-and-seek:

A: I’ve been looking for you for the last hour.
Hili: You could’ve taken a look into the wardrobe an hour ago and you would have found me.

Ja: Od godziny cię szukam.
Hili: Mogłeś godzinę temu zajrzeć do szafy, od razu byś mnie znalazł.

Categories: Science

Fungus-controlled robots tap into the unique power of nature

Matter and energy from Science Daily Feed - Wed, 09/04/2024 - 4:23pm
In creating a pair of new robots, researchers cultivated an unlikely component, one found on the forest floor: fungal mycelia. By harnessing mycelia's innate electrical signals, the researchers discovered a new way of controlling 'biohybrid' robots that can potentially react to their environment better than their purely synthetic counterparts.
Categories: Science

Fungus-controlled robots tap into the unique power of nature

Computers and Math from Science Daily Feed - Wed, 09/04/2024 - 4:23pm
In creating a pair of new robots, researchers cultivated an unlikely component, one found on the forest floor: fungal mycelia. By harnessing mycelia's innate electrical signals, the researchers discovered a new way of controlling 'biohybrid' robots that can potentially react to their environment better than their purely synthetic counterparts.
Categories: Science

Dark Oxygen Could Change Our Understanding of Habitability

Universe Today Feed - Wed, 09/04/2024 - 4:07pm

The discovery of dark oxygen at an abyssal plain on the ocean floor generated a lot of interest. Could this oxygen source support life in the ocean depths? And if it can, what does that mean for places like Enceladus and Europa?

What does it mean for our notion of habitability?

Oxygen is key to complex life on Earth, where photosynthesis generates most of it. The Great Oxygenation Event (GOE), which occurred about 2.5 billion years ago, led to the development of complex life and changed Earth forever. In the GOE, the oxygen was generated by living things.

Our notions of habitability rest on a planet’s proximity to its star, and part of that is because we know that the Sun drives life on Earth by allowing water to remain liquid and providing energy for organisms. But dark oxygen on the ocean floor is strictly abiotic, meaning no life was involved in its production and sunlight isn’t involved.

In recent years, we’ve learned that other Solar System bodies, far beyond the circumstellar habitable zone, could be habitable. The icy ocean moons of Europa, Ganymede, and Enceladus may harbour vast, warm oceans under frigid caps of ice. If Earth produces dark oxygen on its ocean floors, maybe these worlds do, too.

New research examines Earth’s dark oxygen and what it might mean for biology here and on other worlds. It’s titled “Dwellers in the Deep: Biological Consequences of Dark Oxygen.” The lead author is Manasvi Lingam from the Department of Aerospace, Physics, and Space Sciences at the Florida Institute of Technology. The research is awaiting peer review.

Dark oxygen comes from metal deposits called polymetallic nodules. These nodules generate enough electricity to drive electrolysis, which splits water molecules apart and releases oxygen. The amount of oxygen is not large, but it’s there, and it’s measurable.

By Hannes Grobe/AWI – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=104756773

“The striking recent putative detection of “dark oxygen” (dark O2) sources on the abyssal ocean floor in the Pacific at ~4 km depth raises the intriguing scenario that complex (i.e., animal-like) life could exist in underwater environments sans oxygenic photosynthesis,” the authors write.

The amount of dark oxygen in the ocean is small, which limits the size of organisms. Organisms use oxygen through diffusion and circulation, and oxygen levels place restraints on the sizes of both types.

Diffusion is a simple process in which nutrients, waste, and water diffuse through a few layers of tissue. Circulation is more complex and involves a heart pumping fluid to an organism’s cells, delivering nutrients and removing waste. The amount of environmental oxygen places limits on the sizes of both types of organisms.

“The maximal sizes attainable by idealized unicellular or multicellular organisms (i.e., constrained by internal or external diffusion processes) for the estimated concentrations of dark O2 may be ~ 0.1–1 mm.,” the authors write.

For animals with circulation systems, the upper size boundary is higher but still limited.

“In contrast, the upper-size bounds of organisms with internal circulation systems for the distribution of oxygen could range between ~ 0.1 cm to ~ 10 cm, with the latter threshold falling under the umbrella of “megafauna,” the researchers explain.

Aside from the size of individual organisms, there’s the overall biomass density. In an optimistic scenario, the researchers report that biomass density could exceed the reported density. “Under optimistic circumstances, the biomass densities might reach as high as ~ 3–30 g m?2, in principle exceeding the reported macrofaunal densities at depths of ~ 4 km in global deep-sea surveys,” the authors write.

This work inspires a multitude of questions. We know that microorganisms in groundwater use dark oxygen. What types of microorganisms have adapted to these ocean dark oxygen environments? What about their metabolism allows them to live there? Have larger organisms adapted to these environments? Did organisms in these environments play a role in the evolution of life on Earth?

The discovery also compels us to consider its implications for astrobiology. On Earth, abyssal deep sea plains represent about 70% of the ocean floor, making them the largest ecosystem on Earth. Even with a low biomass density, the region is significant.

This cross-section of an oceanic basin shows the relationship of the abyssal plain to a continental rise and an oceanic trench. On Earth, 70% of the sea floor is abyssal plain, making it the largest ecosystem on Earth. Image Credit: By Chris_huh – Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=1812130

When considering the habitability of the ocean moons, we’re at a disadvantage. We don’t know what the sea floors look like on these bodies. In fact, despite all of the enthusiasm, we don’t even know for certain if these moons have oceans. We also don’t know if the oceans, if any of them exist, can produce polymetallic nodules that generate dark oxygen.

However, there are other ways dark oxygen can be generated without nodules. One of them is radiolysis.

Radiolysis is the breaking apart of molecules by ionizing radiation, and there’s plenty of that in the vicinity of Jupiter. Spacecraft have spotted O2 trapped in bubbles on Europa, Ganymede, and Callisto. Does that mean it’s available for life that might exist in their hypothetical oceans?

Radiation from Jupiter can break apart molecules on Europa’s surface. This can free oxygen, which could percolate in brines through the surface into the ocean under the ice. Credit: NASA/JPL-Caltech

“The production of oxidants on the surface and their delivery to the ocean can effectively input O2 to the latter even sans photosynthesis,” the authors explain. Europa’s icy shell isn’t all solid ice. Scientists think that briny liquid can percolate through the ice, and that could potentially deliver surface dark oxygen to the ocean.

There’s a third pathway for dark oxygen called microbial dismutation. Though it’s biotic, it doesn’t rely on photosynthesis. It could be an overlooked source of oxygen.

The evidence we have so far says that worlds like Earth are extremely rare, while environments like Europa could be widespread. “To round off our preliminary venture into this eclectic subject, we reiterate our
prefatory statement that marine habitable settings implausible for photosynthesis, especially on icy worlds with subsurface oceans, are likely widespread in the Universe,” the authors write in their conclusion.

“Therefore, if dark oxygen production is feasible and commonplace on this class of worlds – whether via seawater electrolysis or the prior two routes – then our analysis may broadly encapsulate the profound consequences of dark oxygen for the prevalence of abiogenesis, complex multicellularity, and perhaps even technological intelligence in the Cosmos,” the authors explain.

The fact that we’ve only now discovered dark oxygen on the ocean floor should make us all pause. We’re discovering things about nature that could be critical in the search for life and habitable worlds. If we can confirm that the so-called ocean moons really do have oceans and that dark oxygen is either produced in or transported to those oceans, then we have to adapt our thinking about habitability. Proximity to a star may not be critical, which would simultaneously broaden our understanding while deepening the mystery of life in the cosmos.

That’s the intriguing part of science. It’s equal part mysteries and answers.

The post Dark Oxygen Could Change Our Understanding of Habitability appeared first on Universe Today.

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