Here’s something I’ve known about for long and I see lots of scientists talking about it. A rotating ball is unstable and would kill the very life that lives on it. If it wasn’t for the moon we wouldn’t exist.

My own view is that the "Rare Earth" hypothesis is the correct one. That we are an aberration. The religious types will take this as proof that God created us.

Combine this with our DNA lineage and achievements and you’ll grasp that our existence itself has always been on a knife-edge.

If we don’t take our existence seriously … nothing like us might crop up ever again. The universe is an extremely dangerous place for life actually.

We won’t be finding aliens any time soon, and, I would argue, if we did, you wouldn’t want to talk to them. Either they would kill us, or we would kill them.

But I think we have the edge.

[This is a very important fact that scientists have known about for a long time. This is a very bizarre twist in understanding life on Earth AND finding life on other planets. The moon is a really weird object with a really weird effect. This is a fact that crops up again and again. It is a very well established fact. A planet, by itself, is too unstable for life to exist. The Moon, which is a very weird object, allows this. It's something I've known about for a long time. See the short quote from the article below. Lots of scientists have pointed this out. Jan]

Here it is:-

Moons may be essential to life

In a press release, study co-author Siegfried Eggl of the University of Illinois at Urbana-Champaign explained further applications of the method in determining the habitability of exoplanets:

“If we can use this method to show there are other moons out there, then there are probably other systems similar to ours. The moon is also likely critical for the evolution of life on our planet, because without the moon the axis tilt of the Earth wouldn’t be as stable, the results of which would be detrimental to climate stability. Other peer-reviewed studies have shown the relationship between moons and the possibility of complex life.”

Maybe the discovery of exomoons is the first step to finding life elsewhere in the cosmos. Understanding the similarities and dissimilarities with our solar system is a great place to start.


Science & Evolution: Sleep Evolved Before Brains. Hydras Are Living Proof.

Studies of sleep are usually neurological. But some of nature’s simplest animals suggest that sleep evolved for metabolic reasons, long before brains even existed.

he hydra is a simple creature. Less than half an inch long, its tubular body has a foot at one end and a mouth at the other. The foot clings to a surface underwater — a plant or a rock, perhaps — and the mouth, ringed with tentacles, ensnares passing water fleas. It does not have a brain, or even much of a nervous system.

And yet, new research shows, it sleeps. Studies by a team in South Korea and Japan showed that the hydra periodically drops into a rest state that meets the essential criteria for sleep.

On the face of it, that might seem improbable. For more than a century, researchers who study sleep have looked for its purpose and structure in the brain. They have explored sleep’s connections to memory and learning. They have numbered the neural circuits that push us down into oblivious slumber and pull us back out of it. They have recorded the telltale changes in brain waves that mark our passage through different stages of sleep and tried to understand what drives them. Mountains of research and people’s daily experience attest to human sleep’s connection to the brain.

But a counterpoint to this brain-centric view of sleep has emerged. Researchers have noticed that molecules produced by muscles and some other tissues outside the nervous system can regulate sleep. Sleep affects metabolism pervasively in the body, suggesting that its influence is not exclusively neurological. And a body of work that’s been growing quietly but consistently for decades has shown that simple organisms with less and less brain spend significant time doing something that looks a lot like sleep. Sometimes their behavior has been pigeonholed as only “sleeplike,” but as more details are uncovered, it has become less and less clear why that distinction is necessary.

It appears that simple creatures — including, now, the brainless hydra — can sleep. And the intriguing implication of that finding is that sleep’s original role, buried billions of years back in life’s history, may have been very different from the standard human conception of it. If sleep does not require a brain, then it may be a profoundly broader phenomenon than we supposed.

Recognizing Sleep

Sleep is not the same as hibernation, or coma, or inebriation, or any other quiescent state, wrote the French sleep scientist Henri Piéron in 1913. Though all involved a superficially similar absence of movement, each had distinctive qualities, and that daily interruption of our conscious experience was particularly mysterious. Going without it made one foggy, confused, incapable of clear thought. For researchers who wanted to learn more about sleep, it seemed essential to understand what it did to the brain.

And so, in the mid-20th century, if you wanted to study sleep, you became an expert reader of electroencephalograms, or EEGs. Putting electrodes on humans, cats or rats allowed researchers to say with apparent precision whether a subject was sleeping and what stage of sleep they were in. That approach produced many insights, but it left a bias in the science: Almost everything we learned about sleep came from animals that could be fitted with electrodes, and the characteristics of sleep were increasingly defined in terms of the brain activity associated with them.

This frustrated Irene Tobler, a sleep physiologist working at the University of Zurich in the late 1970s, who had begun to study the behavior of cockroaches, curious whether invertebrates like insects sleep as mammals do. Having read Piéron and others, Tobler knew that sleep could be defined behaviorally too.

She distilled a set of behavioral criteria to identify sleep without the EEG. A sleeping animal does not move around. It is harder to rouse than one that’s simply resting. It may take on a different pose than when awake, or it may seek out a specific location for sleep. Once awakened it behaves normally rather than sluggishly. And Tobler added a criterion of her own, drawn from her work with rats: A sleeping animal that has been disturbed will later sleep longer or more deeply than usual, a phenomenon called sleep homeostasis.

A figure showing some of the body postures of cockroaches, which the researcher Irene Tobler used as diagnostics for sleep in the insects.

Courtesy of Irene Tobler

Tobler soon laid out her case that cockroaches were either sleeping or doing something very like it. The response from her colleagues, most of whom studied higher-order mammals, was immediate. “It was heresy to even consider this,” Tobler said. “They really made fun of me in my early years. It wasn’t very pleasant. But I sort of felt time would tell.” She studied scorpions, giraffes, hamsters, cats — 22 species in all. She was convinced that science would eventually confirm that sleep was widespread, and in later studies of sleep, her behavioral criteria would prove critical.

Those criteria were on the minds of Amita Sehgal at the University of Pennsylvania School of Medicine, Paul Shaw (now at Washington University School of Medicine in St. Louis) and their colleagues in the late 1990s. They were part of two independent groups that had begun to look closely at the quiescence of fruit flies. Sleep was still largely the domain of psychologists, Sehgal says, rather than scientists who studied genetics or cell biology. With respect to mechanisms, from a molecular biologist’s perspective, “the sleep field was sleeping,” she said.

However, the neighboring field of circadian clock biology was exploding with activity, following the discovery of genes that regulate the body’s 24-hour clock. If molecular mechanisms behind sleep could be uncovered — if a well-understood model organism like the fruit fly could be used to study them — then there was the potential for a revolution in sleep science as well. Flies, like Tobler’s cockroaches and scorpions, could not be easily hooked up to an EEG machine. But they could be observed minutely, and their responses to deprivation could be recorded.

With Less and Less Brain

In January 2000, Sehgal and her colleagues published their paper asserting that flies were sleeping. That March, Shaw and colleagues published their parallel work confirming the claim. The field was still reluctant to admit that true sleep existed in invertebrates, and that human sleep could be usefully studied using flies, Shaw says. But the flies proved their worth. Today more than 50 labs use flies to study sleep, generating findings that suggest that sleep has a set of core features present across the animal kingdom. And biologists did not stop with flies. “Once we showed that flies slept,” Shaw said, “then it became possible to say that anything slept.”

The sleep that researchers studied in other species was not always similar to the standard human variety. Dolphins and migrating birds can send half their brain to sleep while appearing awake, researchers realized. Elephants spend almost every hour awake, while little brown bats spend almost every hour asleep.

In 2008, David Raizen and his colleagues even reported sleep in Caenorhabditis elegans, the roundworm widely used as a model organism in biology laboratories. They have only 959 body cells (apart from their gonads), with 302 neurons that are mostly gathered in several clusters in the head. Unlike many other creatures, C. elegans does not sleep for a portion of every day of its life. Instead, it sleeps for short bouts during its development. It also sleeps after periods of stress as an adult.

The evidence for sleep in creatures with minimal nervous systems seemed to reach a new high about five years ago with studies of jellyfish. The Cassiopea jellies, about four inches long, spend most of their time upside down, tentacles reaching toward the ocean surface, and pulsating to push seawater through their bodies. When Michael Abrams, now a fellow at the University of California, Berkeley, and two other graduate students at the California Institute of Technology asked if Cassiopea might sleep, they were continuing the line of inquiry that Tobler had followed when she studied cockroaches, investigating whether sleep exists in ever simpler organisms. If jellyfish sleep, that suggests sleep may have evolved more than 1 billion years ago and could be a fundamental function of almost all organisms in the animal kingdom, many of which do not have brains.

The “upside down” Cassiopea jellyfish does not have a centralized nervous system but it sleeps. The animals never stop moving completely, but at night their rate of pulsations slows, and they show other behaviors associated with sleep.

Jacopo Werther

That’s because, among animals, jellyfish are evolutionarily about as far away as you can get from mammals. Their neighbors in the tree of life include the sponges, which spend their lives attached to rocks in the ocean, and placozoans, tiny clusters of cells first seen by scientists on the walls of seawater aquariums. Unlike other creatures observed sleeping, Cassiopea have no brain, no centralized nervous system. But they can move, and they have periods of rest. It should be possible, the Cal Tech students reasoned, to apply the criteria for behavioral sleep to them.

The first few boxes were relatively easy to check. Although the jellyfish pulsed night and day, Abrams and his collaborators showed that the rate of pulsing slowed in a characteristic way at night, and that animals could be roused from this state with some effort. (There were also indications that the jellyfish favored a particular posture on a platform in the tank during these quieter periods, but Abrams considers that evidence to still be anecdotal.) Testing whether the jellyfish had sleep homeostasis was much harder and required finding ways to gently disturb them without distressing them. In the end, Abrams and his collaborators settled on dropping the platform out from underneath them; when that happened, the Cassiopea would sink and rise again, pulsing at their daytime rate.

The pulsation of a Cassiopea jellyfish can be observed in this series of photos, taken from above. The outer rim of the animal is relaxed at left. It contracts over the next two images, and then relaxes again. The rate of this pulsation helps to indicate sleep in the jellyfish.

Courtesy of Michael Abrams

Later, the telltale signs of homeostatic regulation were there: The more the jellyfish were disturbed, the less the creatures moved the next day. “We weren’t sold on it until we saw the homeostatic regulation,” Abrams said. The team’s results were published in 2017, and Abrams has continued to probe the jellyfish’s genetics and neuroscience since then.

Sleeping in Context

The new revelations about sleep in hydras push the sleep discoveries to a new extreme. The hydra’s body and nervous system are even more rudimentary than Cassiopea’s. Yet as the researchers from Kyushu University in Japan and Ulsan National Institute of Science and Technology in South Korea demonstrated, once a hydra entered a rest state, a pulse of light would rouse it, and it too slept longer after repeated deprivation, among other findings.

Hydra sleep has its peculiarities: Dopamine, which usually makes animals sleep less, caused the hydra to go still. The hydra does not seem to sleep on a 24-hour cycle, instead spending part of every four hours asleep. Something about the hydra’s way of life may have made these traits advantageous, Tobler suggests.

When it is active, a hydra uses its tentacles to ensnare passing prey. The hydra then pulls its victim into its mouth.

Tom Branch/Science Source

But despite those differences, hydra sleep may overlap with other animals’ sleep at the genomic level. When the researchers looked for gene activity altered by sleep deprivation in hydras, they saw a few familiar ones. “At least some genes conserved in other animals are involved in sleep regulation in hydra,” wrote Taichi Itoh, an assistant professor at Kyushu University and a leader of the new study, in an email to Quanta. That finding suggests that the Cnidaria phylum of animals, which includes hydras and jellyfish, already had some genetic components of sleep regulation before it diverged from the ancestors of other groups of animals. As those animals gradually evolved centralized nervous systems, sleep may have taken on new functions for maintaining them.

What, then, does sleep do in the absence of a brain? Raizen suspects that at least for some animals, sleep has a primarily metabolic function, allowing certain biochemical reactions to take place that can’t happen during waking hours. It may divert the energy that would be used by alertness and movement into other processes, ones that are too costly to take place while the animal is awake. For example, C. elegans seems to use sleep to enable the growth of its body and support the repair of its tissues. In sleep-deprived hydras, the cell divisions that are part of everyday life are paused. Something similar has been seen in the brains of sleep-deprived rats and in fruit flies. Managing the flow of energy may be a central role for sleep.

All this research on very simple sleepers raises questions about the very first organism that slept. This first sleeper, whatever it was, probably vanished more than 1 billion years ago. If it was the common ancestor between hydras and humans, it likely had neurons and something like muscle that enabled it to move — and the absence of that movement was characteristic of its version of sleep, fulfilling its special needs.

“If that animal slept, sleep was for whatever that context was,” Abrams said. Sleep might have helped to maintain the first sleeper’s rudimentary nervous system, but it could just as easily have been for the benefits of its metabolism or digestion. “Before we had a brain, we had a gut,” he said.

Even deeper questions are now being asked. In a 2019 opinion paper, Raizen and his co-authors wondered: If sleep happens in neurons, then what is the minimum number of neurons that can sleep? Can the need for sleep be driven by other kinds of cells, as work implicating liver and muscle cells suggests?

“If you really want to push the envelope, do animals that do not have neurons at all sleep?” Raizen asked.

In fact, there are a few organisms whose behavior might someday reveal the answer. Placozoans, the microscopic multicellular creatures that seem to be among the simplest in the animal kingdom, move and react to their surroundings. They have no neurons and no muscles. Neither do sponges, which are anchored in place but still respond to their environment.

“I’m often asked, ‘Do sponges sleep?’” said Abrams. “That’s a whole new world. There might be ways to test that.”


US astronomy’s 10-year plan is super-ambitious

Its ‘decadal survey’ pitches big new space observatories, funding for large telescopes and a reckoning over social issues plaguing the field.

An observatory at night, shown with the stars "circling" the sky from a long exposure.

With input from many astronomers, ‘decadal surveys’ periodically help to set the priorities for US astronomy.Credit: Stan Honda/AFP via Getty

A long-anticipated road map for the next ten years of US astronomy is here — and it’s nothing if not ambitious.

It recommends that NASA coordinate, build and launch three flagship space observatories capable of detecting light over a broad range of wavelengths. It suggests that the US National Science Foundation (NSF) fund two enormous ground-based telescopes in Chile and possibly Hawaii, to try to catch up with an advanced European telescope that’s under construction. And for the first time, it issues recommendations for how federal agencies should fight systemic racism, sexism and other structural issues that drive people out of astronomy, weakening the quality of the science.

“There are tremendous scientific opportunities before us — twenty-first-century astrophysics is incredibly rich,” says Fiona Harrison, an astrophysicist at the California Institute of Technology in Pasadena and co-chair of the steering committee that wrote the report, known as Astro2020. The plan, released on 4 November, attempts to capitalize on some of those opportunities while also being realistic about budget and schedule constraints, she says.

How the fight over a Hawaii mega-telescope could change astronomy

US astronomy has sometimes taken a haphazard approach to building research facilities. Astro2020 is “imposing order on the field in a way that probably hasn’t been done before”, says Matt Mountain, president of the Association of Universities for Research in Astronomy in Washington DC. For instance, Astro2020 describes how the NSF could consider withdrawing its support from either of the large ground-based telescopes if they fail to reach certain milestones. It also sets out the deliberate steps NASA should take to develop technology for its ambitious space missions.

NASA, the NSF, the US Department of Energy (DOE) and the US Air Force commissioned the US National Academies of Sciences, Engineering, and Medicine to research and produce Astro2020. It is the latest in a series of ‘decadal surveys’ that aim to guide the direction of US astronomy and astrophysics, by gathering input from thousands of astronomers every ten years. “They’re influential because they really do let the whole community speak their voice,” says Aki Roberge, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Funding agencies generally follow the decadal survey’s recommendations, which means that billions of dollars are at stake.

Many astronomers welcome the vision laid out in the new report. “They really set the whole framework for how we can go about doing this ambitious science,” says Scott Gaudi, an astronomer at The Ohio State University in Columbus. “It’s a very balanced view,” adds Priyamvada Natarajan, an astrophysicist at Yale University in New Haven, Connecticut. “I like that they really acknowledge that it takes time for the science and technology for missions to mature.”

A forced partnership

Astronomers have been worried about the United States falling behind Europe, which is building the Extremely Large Telescope in Chile. Slated to come online in 2028, that facility is larger and further along than either of the extremely large US telescope projects under way. The 24.5-metre-wide Giant Magellan Telescope (GMT) is under construction in Chile, and the Thirty Meter Telescope (TMT) is planned for the Hawaiian mountain of Maunakea; Astro2020 recommends that the NSF buy into both of them, to help the country catch up.

A rendering of The Giant Magellan Telescope, currently being constructed at Las Campanas Observatory in Chile.

The Giant Magellan Telescope (artist’s rendering shown) is under construction in Chile.Credit: GMTO Corporation/M3 Engineering

Under this arrangement, the GMT and the TMT, once bitter rivals, would partner to cover skies in both the Northern and Southern hemispheres, which the European telescope cannot do. Together, they could make new types of astronomical discovery in galaxy evolution, exoplanet studies and other fields. “The only way to have astronomy in the United States be competitive at this scale is with this kind of capability,” says John O’Meara, chief scientist at the W. M. Keck Observatory in Kamuela, Hawaii.

The decadal survey’s recommendation would deliver a much-needed boost in funding: the GMT is estimated to cost at least US$2 billion and the TMT $2.6 billion, but neither has all the money it needs. Both began as privately funded projects. Buy-in from the US federal government — the NSF might consider investing $800 million in each — would give all US astronomers a chance to compete for a portion of observing time on both telescopes.

But it’s not clear whether the NSF could afford to support both facilities. So Astro2020 lays out a process for deciding whether to jettison one of the telescopes if need be.

NASA won’t rename James Webb telescope — and astronomers are angry

It remains to be seen how the TMT might move forward, however. The project is planned for Maunakea — one of the best sites in the world for stargazing — but construction there has been halted since 2015 owing to protests from Native Hawaiians, to whom the mountain is sacred. The TMT’s back-up site, on the island of La Palma in Spain’s Canary Islands, seemed to be knocked out of the running in July, when a court annulled the agreement that the TMT would need to build there. The project is appealing against the decision, but remains focused on building relationships at the preferred site in Hawaii, says Kerry Slater, the TMT’s vice-president of communications.

Other priorities on Astro2020’s wishlist for ground-based projects are a next-generation cosmology experiment in Antarctica and Chile that would probe the cosmic microwave background, commonly known as the afterglow of the Big Bang, and a major upgrade to the existing Very Large Array radio telescopes scattered across North America.

Triple threat

In addition to ground-based astronomy, the report provides guidance on the future of space-based missions, typically the most expensive and highest-profile astronomical observatories. Recommendations from previous decadal surveys have led to iconic spacecraft such as the Hubble Space Telescope. This time around, the top recommendation is to launch not one, but three flagship observatories, spanning different wavelengths of light to enable a variety of discoveries. The last time NASA coordinated projects in this way was between 1990 and 2003, when the agency launched four satellites dubbed the Great Observatories, beginning with Hubble.

A future NASA space telescope, recommended by Astro2020, could be a scaled-down version of this one, shown as an artist’s illustration.Credit: NASA GSFC

First out of the gate in the next set of missions, which some astronomers are calling the ‘New Great Observatories’, would be a space telescope similar to Hubble, but with a mirror more than twice the width of Hubble’s. It would detect light in ultraviolet, visible and near-infrared wavelengths, and be able to discover objects of astrophysical interest ranging from habitable planets to violent black holes. It would cost around $11 billion and launch in the early 2040s.

Second and third would be missions detecting X-rays, a sector of the electromagnetic spectrum in which some of the most powerful astrophysical phenomena can be observed, and far-infrared radiation, which can penetrate the shrouds of dust around newborn stars. These missions would cost $3 billion to $5 billion each, and a decision on whether to build them would be made five years after the start of the first Hubble-like mission.

Lurking behind these ambitious spacecraft is the spectre of previous space missions whose budgets have blown out of control. Neither of the top recommendations for large space-based missions from the past two decadal surveys are operational yet. The James Webb Space Telescope, the leading recommendation in the 2000 survey, is set to launch on 18 December, years later than intended, at a cost of nearly $10 billion — well above its original budget. The Nancy Grace Roman Space Telescope, the main recommendation in the 2010 survey, had to accommodate a 2.4-metre primary mirror donated by a spy-satellite programme, which was supposed to save money but required design changes and extra processing that drove up the cost. The COVID-19 pandemic added costs and delays, and Roman is now targeted to launch no earlier than 2027, at a cost of $4.3 billion.

Astronomy impasse: What’s next for the Thirty Meter Telescope?

“We’ve learned a lot in the course of the last 10–20 years about how to do large missions,” says Gaudi. “For me, it’s almost inconceivable that we couldn’t do better the next time, because we’ve learned from our past mistakes.”

Astro2020 recommends that NASA save money by, among other things, terminating the Stratospheric Observatory for Infrared Astronomy, a telescope-on-a-plane that has come under criticism for its relatively high operational price tag — nearly as much as Hubble’s — and relatively low scientific output so far, although that is improving. At the same time, the report advises that the agency fund mid-sized space missions, such as astrophysics spacecraft on the order of $1.5 billion each.

A human endeavour

Astro2020 also attempts to grapple with the importance of equity and inclusion to the health of US astronomy. “Astrophysics is done by humans,” says Jane Rigby, an astrophysicist at the Goddard centre. “How these humans treat each other, how they are led, how they hold each other accountable, what the policies and the systems are that they’re working in — this makes so much of a difference to the quality of the science that gets done.”

Hundreds of demonstrators gathered by the Maunakea Access Road in Hawaii to halt telescopes being built on sacred land.

Native Hawaiians have been protesting the construction of a new, extremely large telescope at Maunakea for years.Credit: Ronit Fahl/Zuma Press

US astronomy has found itself at the forefront of many social issues, such as the ethics of doing science on lands seized from Indigenous groups — such as Maunakea. The field has also faced widespread problems of sexism and racism in science, including a sexual harassment scandal surrounding prominent astronomer Geoff Marcy.

The report lays out some recommendations for reducing the systemic barriers that block many people from entering and staying in science. They include increasing federal funding for student and early-career researchers, making diversity a criterion in awarding grants, and gathering data to better track the lack of equity in funding. Collecting such data is the first crucial step towards distributing resources equitably, Natarajan says.

“Racial/ethnic diversity among astronomy faculty remains, in a word, abysmal,” the report says. Indigenous people are even more under-represented in astronomy than in other physical sciences, it notes, while calling for “a new model for respectful, collaborative decision-making in partnership with Indigenous and other local communities”.

NASA won’t rename James Webb telescope — and astronomers are angry

Attention will now turn to how the survey’s recommendations might become reality. Pandemic-related delays in the report’s release mean that the NSF, NASA and the DOE have already missed their chance to incorporate the findings into the budgets they are drawing up for the 2023 fiscal year. As a result, Astro2020 priorities will not start receiving funding until 2024 at the earliest. NASA says it will respond in detail to the recommendations within about ten weeks.

“It is now the community’s job to translate these words into actions,” says Tony Beasley, director of the National Radio Astronomy Observatory in Charlottesville, Virginia.


INCREDIBLE: Scientists discover the first planet outside our Galaxy – in another galaxy!! – My Comments

[The state of Western science is insane. These distances are beyond imagination and all this equipment and these methods were invented by Whites. Just read this article and try to grasp the insane distances that are involved. The accuracy of our science is beyond imagination. Truly. Jan]

Astronomers have found hints of what could be the first planet ever to be discovered outside our galaxy.

Nearly 5,000 "exoplanets" – worlds orbiting stars beyond our Sun – have been found so far, but all of these have been located within the Milky Way galaxy.

The possible Saturn-sized planet discovered by Nasa’s Chandra X-Ray Telescope is in the Messier 51 galaxy.

This is located some 28 million light-years away from the Milky Way.

This new result is based on transits, where the passage of a planet in front of a star blocks some of the star’s light and yields a characteristic dip in brightness that can be detected by telescopes.

This general technique has already been used to find thousands of exoplanets.

Dr Rosanne Di Stefano and colleagues searched for dips in the brightness of X-rays received from a type of object known as an X-ray bright binary.

These objects typically contain a neutron star or black hole pulling in gas from a closely orbiting companion star. The material near the neutron star or black hole becomes superheated and glows at X-ray wavelengths.

Because the region producing bright X-rays is small, a planet passing in front of it could block most or all of the rays, making the transit easier to spot.

The team members used this technique to detect the exoplanet candidate in a binary system called M51-ULS-1.

"The method we developed and employed is the only presently implementable method to discover planetary systems in other galaxies," Dr Di Stefano, from the Harvard-Smithsonian Center for Astrophysics in Cambridge, US, told BBC News.

"It is a unique method, uniquely well-suited to finding planets around X-ray binaries at any distance from which we can measure a light curve."

The Chandra telescope was launched in 1999 to study X-ray emission from hot regions of the Universe

Future planet-hunting

This binary contains a black hole or neutron star orbiting a companion star with a mass about 20 times that of the Sun. A neutron star is the collapsed core of what had once been a massive star.

The transit lasted about three hours, during which the X-ray emission decreased to zero. Based on this and other information, the astronomers estimate that the candidate planet would be around the size of Saturn, and orbit the neutron star or black hole at about twice the distance Saturn lies from the Sun.

Dr Di Stefano said the techniques that have been so successful for finding exoplanets in the Milky Way break down when observing other galaxies. This is partly because the great distances involved reduce the amount of light which reaches the telescope and also mean that many objects are crowded into a small space (as viewed from Earth), making it difficult to resolve individual stars.

With X-rays, she said, "there may be only several dozen sources spread out over the entire galaxy, so we can resolve them. In addition, a subset of these are so bright in X-rays that we can measure their light curves.

"Finally, the huge emission of X-rays comes from a small region that can be substantially or (as in our case) totally blocked by a passing planet."

Messier 51 is also called the Whirlpool Galaxy because of its distinctive spiral shape

The researchers freely admit that more data is needed to verify their interpretation.

One challenge is that the planet candidate’s large orbit means it would not cross in front of its binary partner again for about 70 years, quashing any attempts to make a follow-up observation in the near-term.

One other possible explanation that the astronomers considered is that the dimming has been caused by a cloud of gas and dust passing in front of the X-ray source.

However, they think this is unlikely, because the characteristics of the event do not match up with the properties of a gas cloud.

"We know we are making an exciting and bold claim so we expect that other astronomers will look at it very carefully," said co-author Julia Berndtsson of Princeton University, New Jersey.

"We think we have a strong argument, and this process is how science works."

Dr Di Stefano said that the new generation of optical and infrared telescopes would not be able to compensate for the problems of crowding and dimness, so observations at X-ray wavelengths would likely remain the primary method for detecting planets in other galaxies.

However, she said a method known as microlensing might also hold promise for identifying extra-galactic planets.

The study has been published in the peer-reviewed journal Nature Astronomy.


Science: Excellent: Exoplanet tally set to pass 4,000 mark – My Comments

[I have been following the topic of exo-planets – planets outside the solar system for some years now. The rate of discovery is picking up faster and faster. I suspect that when new specialised satellites get going, you'll see the pace of discoveries picking up EXPONENTIALLY FASTER. I suspect within a decade or two they'll be finding planets at insane speeds and the discoveries will run into the millions and later the billions – just like with stars. It's going to be incredible. Western science totally smokes. Jan]

The number of planets detected around other stars – or exoplanets – is set to hit the 4,000 mark.

The huge haul is a sign of the explosion of findings from searches with telescopes on the ground and in space over the last 25 years.

It’s also an indication of just how common planets are – with most stars in the Milky Way hosting at least one world in orbit around them.

That’s something astronomers couldn’t be certain of just 30 years ago.

The Extrasolar Planets Encyclopedia, run by the Observatoire de Paris, has already passed the 4,000 mark.

Dr Françoise Roques, from the observatory, who is on the scientific board of the encyclopedia, told BBC News: "The great news is that we shift from a starry sky to a planetary sky, as there are more planets than stars.

"And also that the planetary systems have great diversity of structure, with planets orbiting zero, one, two… stars, or other planets."

The Nasa Exoplanet Archive is 74 planets away from the milestone. But there are 443 planet candidates detected by Nasa’s Tess space telescope (launched in 2018) awaiting confirmation.

There are a further 2,423 candidates detected by the Kepler space telescope.

The latest exoplanet to be added to the Nasa archive was the Super Earth GI 686 b, which orbits a red dwarf star (a type cooler than our Sun) which was discovered using ground telescopes. It was added on 21 March.

The total number of confirmed planets differs between the two catalogues because of slightly different acceptance criteria – along with other factors.

The early technique of detecting new worlds by the "wobble" induced by a planet’s gravitational tug on its star yielded many giant planets known as "hot Jupiters", which orbited close to their stars. These planet types were easier to detect using the wobble method.

Nasa’s Kepler space telescope was launched in 2009; it used a different technique known as the transit method to measure the dip in brightness as a planet passed in front of its host star. Kepler discovered hundreds of Neptune-sized planets and those that fell into a category known as Super Earths (those having a mass larger than Earth’s but below those of Neptune-sized planets).

Dr Roques said it remained a difficult task to distinguish between a type of star known as a brown dwarf and giant planets.

"Four-thousand is just a number as the frontier of the planet domain is uncertain," she said.

"The brown dwarfs have been defined by the [IAU – International Astronomical
Union] as small stars, but in fact, some of them are big planets. Our database collects objects until 60 Jupiter masses and contains a mix of the planetary brown dwarfs (formed in a protoplanetary disk around a star) and starry brown dwarfs (formed by collapse of interstellar cloud).

"The only way to ensure the difference is to access its internal structure, which is a difficult/ impossible task."

The first exoplanets were found around a pulsar – a highly magnetised neutron star – in 1992 by Aleksander Wolszczan and Dale Frail.

The initial discovery of a planet around a main sequence star – those that fuse hydrogen into helium within their cores – was made in 1995 by astronomers Didier Queloz and Michel Mayor.

Dr Roque explained: "For the field of exoplanet exploration, we [are
going] from discovery projects to exploration projects, for a better understanding of the structure, formation, atmosphere and, of course habitability of exoplanets."


Photo: Earth has had TWO Moons for the last 3 years…

[This is quaint. We have pieces of rock that come into orbit and later leave. Jan]

Until recently, many of us earthlings were blissfully unaware that our planet had gained a second moon. But now 2020 CD3 has become such a superstar, we’re using giant telescopes just to catch a glimpse of it.

Part-time paparazzi, full-time astronomers at the Gemini Observatory in Hawaii snapped the stunning pictures of the car-sized carbonaceous rock using the 8-meter Gemini North telescope.

The image is actually a combination of three separate images using three different filters to capture our new natural satellite in all its glory.

"Obtaining the images was a scramble for the Gemini team because the object is quickly becoming fainter as it moves away from Earth," explains Gemini Observatory astronomer John Blakeslee, adding that the new celestial superstar 2020 CD3 is expected to leave us forever some time in April.

Fear not, as there are already rumors circulating of a new generation of mini-moons that could already be orbiting the Earth.

"We expect to find a population of these objects once the Rubin Observatory is operational," said Grigori Fedorets, the lead astronomer for the Gemini observations, referencing the Vera C. Rubin Observatory, whose sole purpose will be to scan the skies for similar, previously unknown, objects.


Amazing Science: These 125 million-year-old fossils may hold dinosaur DNA – My Comments

[This is astounding. This normally is not possible. This is moving things to a whole new level as bits and pieces of older and older DNA is found … something previously impossible! So much can be learned from this. Jan]

The remnants of DNA may lurk in 125 million-year-old dinosaur fossils found in China. If the microscopic structures are indeed DNA, they would be the oldest recorded preservation of chromosome material in a vertebrate fossil.

DNA is coiled inside chromosomes within a cell’s nucleus. Researchers have reported possible cell nucleus structures in fossils of plants and algae dating back millions of years. Scientists have even suggested that a set of microfossils from 540 million years ago might hold preserved nuclei.

These claims are often controversial, because it can be hard to distinguish a fossilized nucleus from a random blob of mineralization created during the fossilization process. In the new study, published Sept. 24 in the journal Communications Biology, researchers compared fossilized cartilage from the feathered, peacock-size dinosaur Caudipteryx with cells from modern chickens; they found structures in the fossils that looked much like chromatin, or threads of DNA and protein.

"The fact that they are seeing this is really interesting, and it suggests we need to do more research as to what happens to DNA and chromosomes after cell death," said Emily Carlisle, a doctoral student who studies microscopic fossils and their preservation at the University of Bristol in England but was not involved in the new research.

To answer the obvious burning question: No, we’re nowhere close to resurrecting dinosaurs from their fossilized DNA.

"If there is any DNA or DNA-like molecule in there, it will be — as a scientific guess — very, very chemically modified and altered," Alida Bailleul, a paleobiologist at the Chinese Academy of Sciences who led the new research, wrote in an email to Live Science.

However, Bailleul said, if paleontologists can identify chromosome material in fossils, they may someday be able to unravel snippets of a genetic sequence. This could reveal a little more about dinosaur physiology.

But first, researchers have to find out if the DNA is even there. Until recently, most paleontologists thought that rot and decay destroyed the contents of cells before fossilization could take hold. Any microscopic structures inside cells were considered collapsed cell contents, such as organelles and membranes, that had rotted before mineralization, Carlisle told Live Science. More recently, though, paleontologists have found legitimate cell structures in a few fossils. For example, 190 million-year-old fern cells described in 2014 in the journal Science were buried in volcanic ash and fossilized so quickly that some were frozen in the process of cell division. Unmistakable chromosomes are visible in some of these cells.

In 2020, Bailleul and her colleagues reported the possible preservation of DNA in the skull of an infant Hypacrosaurus, a kind of duck-billed dinosaur that lived 75 million years ago, found in Montana. The possible DNA was found in cartilage, the connective tissue that makes up the joints.

For the new study, the researchers turned to a well-preserved specimen of Caudipteryx held by the Shandong Tianyu Museum of Nature in China. Originally discovered in the northeastern province of Liaoning, the fossil has ample preserved cartilage, which the researchers stained with the same dyes used to image DNA in modern tissue. These dyes bind to DNA and turn it a specific color, depending on the dye, allowing the DNA to stand out against the rest of the nucleus. By examining the stained, fossilized cartilage with several microscopy methods, Bailleul and her team showed that the cartilage cells contain structures that look just like nuclei with a scramble of chromatin inside.

The stained dinosaur nuclei’s resemblance to modern cells doesn’t prove there is DNA inside them, though, Bailleul cautioned. "What it means is that there are definitely parts of original organic molecules, perhaps some original DNA in there, but we don’t know that yet for sure," she said. "We just need to go figure out exactly what these organic molecules are."

The imaging definitely seems to show nuclei, Carlisle said, but it’s harder to identify fossilized chromosomes, because no one really knows what happens to chromosomes as they decay. It’s possible that the contents of the nucleus might just collapse into structures that look like chromosomes but are really just a jumble of meaningless mineralized junk; it’s also possible that the fossilization process preserves some of the original molecular structure. (One 2012 study suggests that DNA in bone will completely break down in about 7 million years, but the timing may depend heavily on environmental factors.)

"It would be really interesting to do more experiments into that, looking at what happens inside the nuclei instead of just what happens to it from the surface," Carlisle said.

Bailleul and her colleagues hope to collect more chemical data to nail down the identity of the mysterious structures.

"I hope we can reconstruct a sequence, someday, somehow," she said. "Let’s see: I could be wrong, but I could also be right."