Miguel Clarois a professional photographer, author and science communicator based in Lisbon, Portugal, who creates spectacular images of the night sky. As aEuropean Southern Observatory photo ambassador,a member ofThe World At Nightand the official astrophotographer of theDark Sky Alqueva Reserve, he specializes in astronomical "skyscapes" that connect Earth and night sky. Join Claro here as he takes us through his photograph"Orion in the Winter Sky and the Story Behind the Fainting Star Betelgeuse."

Captured during one of my private workshops on Dec. 12, 2019, this image shows a lonely stargazer enjoying the most beautiful constellation of the winter sky: Orion, the hunter.

The photo, captured from one of the landscapes of Dark Sky Alqueva Reserve in Portugal, features the bright star Betelgeuse, which is located on the hunter's left "shoulder." Many amateur and professional astronomers since last October have been reporting a decrease in brightness of the yellow-orange star, giving space for some speculation that the star is about to explode.

Related: The dimming star Betelgeuse is acting weird. Here's how to spot it in Orion's shoulder.

According to an article published by National Geographic last December, "decades of photometric data show that Betelgeuse brightens and dims in cycles, with one notable cycle vacillating on a roughly six-year time scale and another rising and falling every 425 days or so."

Scientists suspect that the red supergiant Betelgeuse has recently dimmed quite dramatically because those two periodic cycles are overlapping at minimal brightness, according to a report published in the Astronomer's Telegram by Edward Guinan, a professor of astronomy and astrophysics at Villanova University in Pennsylvania.

Astronomers have long suspected that the star might explode sometime in the next million years. It's also possible that Betelgeuse has already exploded and we just haven't seen it happen; because the star is 600 light-years away, it takes 600 years after something happens on Betelgeuse for light from that event to reach Earth. But if and when astronomers do witness the star's explosion, it will be the most astonishing astronomy event of all time.

When Betelgeuse explodes, turning into a supernova, it will briefly shine even brighter than the full moon. Then, the star will vanish forever, leaving an "empty space" in our hearts and in the mythic Orion constellation, which will still be visible in the night sky for us and many future civilizations. Without his left shoulder, however, the hunter will never look the same.

To capture this single shot, I used a Nikon D810A camera with the ISO set to 2500 and a 24-70mm lens set to 26mm at f/2.8. The exposure time was 15 seconds.

To get a print of Claro's amazing astrophotography, visit his fine-art prints store atwww.miguelclaro.com/prints. Follow us on Twitter@Spacedotcomand onFacebook.

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Orion and its dimming star Betelgeuse shine over a stargazer in this sentimental night-sky photo - Space.com

Monday, February 17Mars rises before 4 a.m. local time and climbs 20 above the southeastern horizon an hour before the Sun comes up. Glowing at magnitude 1.2 against the fainter background stars of Sagittarius the Archer, the ruddy world stands out nicely in the predawn darkness. But the real reason you should target Mars through binoculars or a telescope this morning is because of the company it keeps: The Red Planet passes between two of the Milky Ways finest star-forming regions, the Lagoon Nebula (M8) and the Trifid Nebula (M20). These two Messier objects lie just 1.4 apart and will make a marvelous backdrop for astroimagers. Unfortunately, a telescope doesnt add much to our view of Mars, revealing a bland disk that measures just 5" across.

Tuesday, February 18As spectacular as Mars passage between M8 and M20 yesterday was, this morning holds even more drama for observers in the western two-thirds of North America. Shortly before dawn, the waning crescent Moon slides in front of the Red Planet in a stunning occultation. You can view this event with your naked eye, but binoculars or a telescope reveal far more detail. Use a scope if you want to watch Mars fade away as Lunas bright limb gradually overtakes it. Depending on your location, the Moon can take up to 15 seconds to completely cover the planets featureless disk. The occultation occurs earlier the farther west you live. Although Mars has already disappeared by the time the two objects rise along the West Coast, observers there can witness the planets equally stunning reemergence from behind the Moons dark limb. Those in the mountain states get to view the disappearance against a dark sky, while Midwesterners see the same event during twilight. Unfortunately, East Coast skygazers miss out because the occultation occurs after the Sun rises. Even so, theyll enjoy a beautiful close conjunction between the two objects before dawn.

Wednesday, February 19Less than an hour after Mars rises, Jupiter pokes above the southeastern horizon. Theres no mistaking the giant planet for any other object at magnitude 1.9, it is by far the brightest point of light in the morning sky. The waning crescent Moon forms a pretty pair with Jupiter this morning, appearing just 4 to the planets right.

Thursday, February 20The Moon moves eastward an average of 13 relative to the background stars each day. That motion carries it into western Sagittarius this morning, where it lies just 2.5 to the lower right of Saturn. The two rise shortly after 5 a.m. local time and appear impressive as twilight starts to brighten the sky. The ringed planet glows at magnitude 0.6, 10 times fainter than its brilliant neighbor, Jupiter.

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The Sky This Week from February 14 to 23 - Astronomy Magazine

Astronomers estimate that there is roughly one exoplanet per star in our galaxy. Of course, some stars have many planets our own Sun has eight. And some stars have none. But if a star lives long enough, forming planets seems to be the rule, rather than the exception.

That doesnt mean astronomers can map all of those billions of stars though. When it comes to exoplanets that have been measured or counted in some way, the numbers are much smaller.

The running counter of known exoplanets as of this writing stands at 4,108 confirmed worlds. But astronomers are surprisingly good at figuring out what they cant see. They know that their telescopes arent powerful or precise enough to see the stealthiest planets those that are very small, very far from their stars, or around stars very far from Earth. And conversely, there are regions of space where astronomers are pretty confident theyve found all the planets within a certain range.

By combining the knowledge of what they can see the known exoplanets with the knowledge of what they cant see the parts of space currently beyond our ability to investigate astronomers end up at the approximation of one planet per star.

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How many planets are there in the universe? - Astronomy Magazine

ReutersFeb 17, 2020 10:19:22 IST

A vaguely hourglass-shaped icy object called Arrokoth residing in the far reaches of the solar system the most distant body ever explored by a spacecraft is giving scientists intriguing clues about the formation of the planets including Earth.

Scientists on Thursday offered the fullest description yet of the composition and origin of Arrokoth based on data from NASAs New Horizons spacecraft, which whizzed past it last year.

Arrokoth, located 6.6 billion km from Earth in a region beyond the planet Neptune called the Kuiper Belt, boasts a uniformly reddish surface that is smooth and undulating with few craters. It is coated with frozen methanol a type of alcohol and unidentified complex organic molecules.

Arrokoth is a planet that is comprised of two lobes looking somewhat like giant wheels of cheese fused together by a bridge. Image credit: NASA

About 36 km long and 20 km wide, it is classified as a planetesimal, objects that were among the solar systems original building blocks. These small bodies coalesced at an early stage of the solar systems formation some 4.5 billion years ago and are a key intermediate size step on the way to building planets.

Arrokoth is comprised of two lobes looking somewhat like giant wheels of cheese fused together by a bridge.

It consists of two bodies that appear to have formed in orbit around each other from a local dust cloud, which collapsed under its own gravity within the solar nebula the huge disk of dust and gas that the solar system formed from.The two bodies then spiralled in together and merged very gently, said astronomer John Spencer of the Southwest Research Institutein Colorado, one of the researchers in the study published in the journal Science.

This suggests that planetesimals formed in localized conditions in which collision speeds were slow rather than from a gradual assembly of widely dispersed objects growing by randomly colliding with each other at higher speeds.

So we now have a clearer picture of how planets, including the Earth, were built, Spencer said.

Planetesimals previously visited by space probes were all badly battered by impactors or cooked by approaching too close to the sun. So it is thrilling to finally be able to see one still pretty much just as it was after its formation, said planetary scientist and study co-author Will Grundy of Lowell Observatory in Arizona, a New Horizons mission co-investigator.

Arrokoth is one of the thousands of small icy bodies inhabiting the Kuiper Belt, the solar systems vast third zone beyond the inner terrestrial planets and the outer gas giant planets. Its name is a Native American term for sky.

Welcome to Tech2 Innovate, Indias most definitive youth festival celebrating innovation is being held at GMR Grounds, Aerocity Phase 2, on 14th and 15th February 2020. Come and experience an amalgamation of tech, gadgets, automobiles, music, technology, and pop culture along with the whos who of the online world. Book your tickets now.

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Planetesimal Arrokoth is helping astronomers understand the formation of the planets - Firstpost

Artists concept of a neutron star. The stars tiny size and extreme density give it incredibly powerful gravity at its surface. Thus this image portrays the space around the neutron star as being curved. Image via Raphael.concorde/ Daniel Molybdenum/ NASA/ Wikimedia Commons.

When at the end of its life a massive star explodes as a supernova, its core can collapse to end up as a tiny and superdense object with not much more than our suns mass. These small, incredibly dense cores of exploded stars are neutron stars. Theyre among the most bizarre objects in the universe.

A typical neutron star has about about 1.4 times our suns mass, but they range up to about two solar masses. Now consider that our sun has about 100 times Earths diameter. In a neutron star, all its large mass up to about twice as much as our suns is squeezed into a star thats only about 10 miles (15 km) across, or about the size of an earthly city.

So perhaps you can see that neutron stars are very, very dense! A tablespoon of neutron star material would weigh more than 1 billion U.S. tons (900 billion kg). Thats more than the weight of Mount Everest, Earths highest mountain.

Neutron stars are the collapsed cores of massive stars. They pack roughly the mass of our sun into a sphere with the diameter of a city. Heres a comparison of a neutron stars typical diameter with the city of Chicago. Graphic via M. Coleman Miller.

Heres how neutron stars form. Throughout much of their lives, stars maintain a delicate balancing act. Gravity tries to compress the star while the stars internal pressure exerts an outward push. The outward pressure is caused by nuclear fusion at the stars core. This fusion burning is the process by which stars shine.

In a supernova explosion, gravity suddenly and catastrophically gets the upper hand in the war it has been waging with the stars internal pressure for millions or billions of years. With its nuclear fuel exhausted and the outward pressure removed, gravity suddenly compresses the star inward. A shock wave travels to the core and rebounds, blowing the star apart. This whole process takes perhaps a couple of seconds.

But gravitys victory is not yet complete. With most of the star blown into space, the core remains, which may only possess a couple of times the mass of our sun. Gravity continues to compress it, to a point where the atoms become so compacted and so close together that electrons are violently thrust into their parent nuclei, combining with the protons to form neutrons.

Thus the neutron star gets its name from its composition. What gravity has created is a superdense, neutron-rich material called neutronium in a city-sized sphere.

What neutron stars are, and are not. If, after the supernova, the core of the star has enough mass, then according to current understanding the gravitational collapse will continue. A black hole will form instead of a neutron star. In terms of mass, the dividing line between neutron stars and black holes is the subject of much debate. Astrophysicists refer to a kind of missing mass, occurring between about two solar masses (the theoretical maximum mass of a neutron star) and five solar masses (the theoretical minimum mass of a black hole). Some expect that this mass bracket will eventually be found to be populated by ultra-lightweight black holes, but until nownone have been found.

The exact internal structure of a neutron star is also the subject of much debate. Current thinking is that the star possesses a thin crust of iron, perhaps a mile or so thick. Under that, the composition is largely neutrons, taking various forms the further down in the neutron star they are.

A neutron star does not generate any light or heat of its own after its formation. Over millions of years its latent heat will gradually cool from an intial 600,000 degrees Kelvin (1 million degrees Fahrenheit), eventually ending its life as the cold, dead remnant of a once-glorious star.

Because neutron stars are so dense, they have intense gravitational and magnetic fields. The gravity of a neutron star is about a thousand billion times stronger than that of the Earth. Thus the surface of a neutron star is exceedingly smooth; gravity does not permit anything tall to exist. Neutron stars are thought to have mountains, but they are only inches tall.

Anatomy of a pulsar. They are neutron stars that are oriented in a particular way with respect to Earth, so that we see them pulse at regular intervals. Image via Roen Kelly/ Discovermagazine.com.

Pulsars: How we know about neutron stars. Although neutron stars were long predicted in astrophysical theory, it wasnt until 1967 that the first was discovered, as a pulsar, by Dame Jocelyn Bell Burnell. Since then, hundreds more have been discovered, including the famous pulsar at the heart of the Crab Nebula, a supernova remnant seen to explode by the Chinese in 1054.

On a neutron star, intense magnetic fields focus radio waves into two beams firing into space from its magnetic poles, much like the beam of a lighthouse. If the object is oriented just so with respect to Earth so that these beams become visible from our earthly viewpoint we see flashes of radio light at regular and extremely precise intervals. Neutron stars are, in fact, the celestial timekeepers of the cosmos, their accuracy rivalling that of atomic clocks.

Neutron stars rotate extremely rapidly, and we can use the radio beams of a pulsar to measure just how fast. The fastest-rotating neutron star yet discovered rotates an incredible 716 times per second, which is about a quarter of the speed of light.

Read more about Jocelyn Bell Burnell, who discovered pulsars

Irish astronomer Jocelyn Bell Burnell was 24 years old when she noticed the odd radio pulses from space that she and her colleagues at first affectionately labeled LGMs, for little green men. Later, they understood that the pulses came from neutron stars. Fast-spinning neutron stars seen by earthly astronomers to emit radio pulses are now called radio pulsars. Image via Wikimedia Commons.

More manifestations of neutron stars in our galaxy. There are estimated to be more than a hundred million neutron stars in our Milky Way galaxy. However, many will be old and cold, and therefore difficult to detect. The unimaginably violent neutron star collisions, one of which was detected in 2017 by the LIGO gravitational wave observatories and designated GW170817, are thought to be where heavy elements like gold and platinum are created, as normal supernovae are not thought to generate the requisite pressures and temperatures.

A neutron star that has an abnormally strong magnetic field is known as a magnetar, able to pull the keys out of your pocket from as far away as the moon. The origin of magnetars is not well understood.

Neutron stars, including magnetars and pulsars, are thought to be responsible for several little-understood phenomena, including the mysterious Fast Radio Bursts (FRBs) and the so-called Soft Gamma Repeaters (SGRs).

Read more about neutron stars:

M. Coleman Miller, a professor of astronomy at University of Maryland, has a great page on neutron stars.

Five extreme facts about neutron stars, from SymmetryMagazine.org

Getting to know pulsars, the lighthouses of the cosmos, from DiscoverMagazine.com

How high are pulsar mountains? from LIGO

Sci fi alert! Dragons Egg by Robert L. Forward (out-of-print) depicts the imaginary inhabitants of the surface of a neutron star. Claudia commented: They were tiny and dense (of course) and lived at a tremendous speed. Its been a while, but I remember it as a good read. Andy added: Yes, I remember that book! Very entertaining. Its incredible to think that if the surface of a neutron star slips by as little as a millimeter, it causes a starquake.

Bottom line: Neutron stars are the collapsed cores of formerly massive stars that have been crushed to an extreme density by supernova explosions. A neutron star isnt as dense as a black hole, but its denser than any other known type of star.

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What is a neutron star? | Astronomy Essentials - EarthSky

Fast radio bursts are one of astronomys tantalizing unsolved mysteries. These sudden pulses of radio waves come from far outside our galaxy. They last about a millisecond. And sometimes, the signals repeat.

Until recently, thats about all scientists could tell you about fast radio bursts, or FRBs. Our radio telescopes, which pick up noise rather than light, first detected them in 2007; since then, weve recorded a few dozen more, but not enough to be able to put together a compelling theory of what causes them.

With the origin of these signals still unknown, some scientists notably the chair of the Harvard astronomy department, Avi Loeb speculate aliens could be sending them.

Now, researchers based in Canada, where a radio telescope exceptionally well equipped to detect FRBs began operating in 2018, have added a new piece to the puzzle. A few previously detected FRBs had been shown to repeat sporadically, without any regular pattern. But by observing the sky from September 2018 through October 2019, the researchers in Canada found 28 bursts including one that repeats with a very regular pattern indeed: It appears every 16.35 days, to be exact.

This is the first time scientists have detected such a pattern in an FRB source. The peculiar signal is coming from a massive spiral galaxy 500 million light-years away. The source sends out one or two bursts of radio waves every hour, over four days. Then it goes quiet for 12 days. Then the whole process repeats.

So why is a radio signal repeating every 16 days like clockwork, and what can that teach us about its origins?

Thats the central question of a new paper authored by the Canadian Hydrogen Intensity Mapping Experiment in collaboration with the Fast Radio Burst Project (CHIME/FRB).

There are a couple of things we know for sure. The 16-day periodicity cannot be occurring by chance coincidence, the scientists write, and its an important clue to the nature of the object. Its clear that the FRB cant be originating from a cataclysmic event, like a star going supernova, since thats a one-time affair.

But beyond that, the scientists really arent sure. They propose a few possibilities.

One explanation is orbital motion. Celestial bodies are known to orbit on regular timescales, so a pair of objects like a star and a black hole could account for the 16-day pattern. Given the sources location in the outskirts of a massive spiral galaxy, the paper says, a supermassive black hole companion seems unlikely, although lower-mass black holes are viable.

The authors say FRBs could be generated if giant radio pulses from an energetic neutron star are eclipsed by a companion object. They also note that periodicity could arise from the rotation of a star, but thats a tricky hypothesis: Previously observed sources have had way shorter periodicities (a few hours, not a couple of weeks) and way less strength (were talking nine orders of magnitude less) than FRBs have.

In short, the authors dont know whats causing FRBs. But aliens are not on their list of possibilities. They end their paper calling for more research.

While grounded speculation among astrophysicists suggests that FRBs are caused by neutron stars, stars merging, or black holes, its a different theory that has caught hold of the public imagination: Maybe theyre caused by intelligent alien life.

A study by Avi Loeb and Manasvi Lingam of Harvard University, published in 2017, argued that the patterns could plausibly result from extraterrestrials transmitters. The paper is theoretical; it doesnt propose any evidence for the aliens hypothesis, it just argues that itd be compatible with the recorded data so far. They concluded itd be physically possible to build such a transmitter if you had a solar-powered, water-cooled device twice the size of Earth.

The hypothesis raises some obvious questions. FRBs come from all over space, not just from one particular region. Are we to assume that these aliens are sophisticated enough to have spread across many galaxies, but that there are no signs of them other than these energy bursts? Or that many civilizations independently settled on the same odd style of energy burst?

The 2017 paper argues for the latter possibility: that many civilizations have separately built such massive transmitters and are sending out FRBs. The latest estimates suggest that there are 10^4 [10,000] FRBs per day, the paper observes, which would suggest an implausible number of extremely busy, scattered alien civilizations. To resolve that, the paper argues that perhaps not all FRBs have an artificial origin only a fraction of them could correspond to alien activity.

But once we concede that FRBs can occur naturally, and conclude that at least some of them are occurring naturally, why conclude that any of them are artificial?

And if a civilization had the astounding technical capacities to build solar-powered, planet-size transmitters, wouldnt it be doing other things we could detect that would be less ambiguous?

The possibility that FRBs are produced by extragalactic civilizations is more speculative than an astrophysical origin, the paper concedes.

Indeed, thats what the CHIME/FRB researchers behind the new paper think. We conclude that the periodicity [of the FRB] is significant and astrophysical in origin.

Scientists disagree about how to interpret phenomena like FRBs in large part because they disagree about how plausible alien life is in the first place. In statistical terms, they have different priors, meaning that the background assumptions they are using to interpret the new evidence are different.

From one perspective, the universe is astonishingly large, full of habitable planets like Earth where life could evolve as it did here. Sometimes, that life would become intelligent. Wed expect such a universe to have lots of flourishing civilizations as well as lots of extinct ones.

This is clearly the expectation that motivates Harvards Loeb. As soon as we leave the solar system, I believe we will see a great deal of traffic out there, he said in a 2019 interview with Haaretz. Possibly well get a message that says, Welcome to the interstellar club. Or well discover multiple dead civilizations that is, well find their remains.

If you think that space is teeming with aliens, its not so much of a stretch to interpret astronomical phenomena as remnants of those aliens.

But if youre looking at the same data with the expectation that were alone in the universe, youre much likelier to conclude that theres a natural explanation for FRBs.

Its weird, given that the universe is so vast, that we seem to be alone in it. Physicist Enrico Fermi was the first to spell out this dilemma, and its named after him: the Fermi paradox. The paradox is that, under some reasonable assumptions about how often life originates and reaches technological sophistication, we should be able to detect signs of thousands or millions of other civilizations. And yet we havent. Recent investigations suggest that the paradox may have a mundane resolution under more accurate assumptions about how life originates, we are very plausibly, alone.

The disagreement between researchers who think advanced civilizations must be extremely rare and those who think theyre common is a fairly substantive one. For one thing, if advanced civilizations are common, then why cant we see them? We might be forced to conclude that theyre fairly short-lived. Thats Loebs take: The technological window of opportunity might be very small, he told Haaretz.

That take would have some consequences for us. If theres some danger ahead that destroys every technological civilization that runs into it, we might expect that were living in a vulnerable world where future technological advances will destroy us, too.

In that way, disagreements over aliens have big implications. But thats probably not the reason everyone cares about them. Offhand speculation about aliens tends to get vastly more coverage than anything else in astronomy. Whether were alone in the universe feels like a profoundly important question, for its implications for human civilization but also for its own sake. The lack of evidence suggesting phenomena like FRBs are alien in origin wont be enough to stop people from wondering.

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What is a fast radio burst? What causes the signal from space? - Vox.com

Since the 1960s, there has been a general consensus among astronomers and cosmologists that the majority of the Universe is made up of an invisible, mysterious mass (known as Dark Matter). While scientists still havent identified the candidate particle that makes up this mass, indirect tests and simulations have shown that Dark Matter must exist in order for the Universe to be the way it is.

In a fascinating twist, a team of European researchers conducted a simulation that looked at a Universe without Dark Matter. Using an alternative theory known as MOdified Newtonian Dynamics (MOND), the team created a computer simulation in which the galaxies were actually very similar to what we see in the Universe today. These findings could help to resolve one of the most enduring mysteries of modern cosmology.

The study that describes their findings (recently published in the Astrophysical Journal) was conducted by the Stellar Populations and Dynamics Research Group (SPODYR) led by Prof. Pavel Kroupa of the Helmholtz Institue for Radiation and Nuclear Physics at the University of Bonn. He was joined by Nils Wittenburg, a doctoral member of SPODYR, and Benoit Famaey the Research Director at the University of Strasbourg.

This theory that gravity behaves differently than previously thought (depending on the scale) was first proposed by Israeli physicist Prof. Dr. Mordehai Milgrom hence the alternative name Milgromian gravity. According to this theory, the attraction between two masses obeys Newtons Laws of Motion (aka. Universal Gravitation) only up to a certain point.

At lower accelerations, as is the case with galaxies, the influence of gravity becomes considerably stronger. In short, the attraction of a body depends not only on its own mass but also on whether other objects are in its vicinity. This theory is a possible explanation for why galaxies do not break apart as a result of their rotational speed.

MOND is also attractive because it makes the existence of Dark Matter (which remains unconfirmed) entirely superfluous. Nevertheless, MOND remains a largely unproven and untested theory, which is what Wittenberg and his colleagues sought to address. With the help of Famaey, the team employed computational software that conducts gravitational computations (which they designed) to simulate a cosmos where MOND exists.

This consisted of simulating the birth of the first stars and galaxies which are believed to have formed between 100,000 and 300,000 years after the Big Bang and how they have evolved since. What they found, interestingly enough, was that the distribution and velocity of the stars in the computer-generated galaxies followed the same pattern as those that are visible in the Universe today.

As Wittenburg, who was the lead author on the study, explained:

In many aspects, our results are remarkably close to what we actually observe with telescopes. Furthermore, our simulation resulted mostly in the formation of rotating disk galaxies like the Milky Way and almost all other large galaxies we know. Dark matter simulations, on the other hand, predominantly create galaxies without distinct matter disks a discrepancy to the observations that is difficult to explain.

In addition, the MOND simulation was virtually immune to changes in parameters, like the frequency of supernovae and their effect on the distribution of matter in galaxies. In the case of simulations where the existence of Dark Matter is assumed, however, changes in these parameters have a considerable effect. This is not to say that the MOND simulations were correct on all points.

For example, the simulations relied on some rather simple assumptions about the distribution of matter and the conditions present during the early Universe. Our simulation is only a first step, Prof. Kroupa emphasized. We now have to repeat the calculations and include more complex influencing factors. Then we will see if the MOND theory actually explains reality.

Invariably, when it comes to the dynamics and behavior of the Universe on the grandest of scales and longest of time periods, the jury is still out. While the existence of Dark Matter remains unproven, it is the only cosmological theory that is consistent with General Relativity an endlessly proven theory and the only working hypothesis for how gravity behaves on cosmological scales.

And while MOND provides some resolution to theoretical problems presented by Dark Matter, it presents problems of its own. In the near future, a number of next-generation observatories that could help resolve this mystery will be going into space including the James Webb Space Telescope (JWST) and the ESAs Euclid mission.

These and other missions will offer a better picture of the geometry of the Universe and improved measurements of the cosmic expansion. From this, scientists hope to gain a better understanding of how Dark Matter could have affected cosmic evolution not to mention Dark Energy, another cosmological mystery that is also the subject of debate!

Further Reading: University of Bonn, arXiv

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Astronomers Simulated How the Universe Would Look Without Dark Matter - Universe Today

Roundup Cygnus flies, SpaceX stands down, Rocket Lab is going to the Moon and New Horizons drops a massive dump (of new data) in this week's roundup. A heck of a way to celebrate the 30th anniversary of a view of Earth from really, really far away.

Northrop Grumman overcame both a delay and some unexpected bonus commentary (in the form of a Verizon interruption) to launch its latest freighter, Cygnus NG-13, to the International Space Station (ISS). The spacecraft, loaded with science and supplies, should turn up at the orbiting outpost at around 0905 UTC on Tuesday.

NASA astronaut Andrew Morgan will use the ISS's robotic arm to capture the Cygnus and install it on the Earth-facing port of the Unity module while fellow 'naut Jessica Meir keeps an eye on things. The spacecraft is scheduled to remain docked to the ISS until May.

The launch marks the 13th successful mission of the freighter. Memorably, the third operational flight ended in a fireball just after launch in 2014 following a catastrophic failure involving the elderly Russian engines of the 130-variant Antares rocket. Excepting a brief flirtation with the Atlas, the Cygnus has continued to fly on the Antares, although using somewhat more recent RD-181 power plant.

The next batch of 60 Starlink satellites remained rooted to a Cape Canaveral pad this weekend as engineers opted to take a look at a potentially iffy valve on the second stage of the launcher.

Our suspicion that an astronomer snuck up in the dead of night and had at the thing with a hammer is, of course, totally unfounded. After all, Elon has said that the albedo issue is going to get better. No, really, it will. Elon said so:

The launch, now scheduled for 17 February, will be the fourth flight for the first stage of the Falcon 9. The stage has lofted two Dragon freighters bound for the ISS, CRS-17 and CRS-18, and, most recently, the JCSAT-18/Kacific1 mission in December 2019. The company plans to recover the first stage once again as well as having another crack at catching the fairing halves.

In a now deleted tweet, NASA's commercial crew tentacle heralded the arrival in Florida of the next Crew Dragon capsule, which will be used for the upcoming Demo-2 mission. Astronauts Bob Behnken and Doug Hurley will clamber into the spacecraft for a trip to the ISS in the coming months.

NASA proudly declared that the SpaceX capsule would be the first to launch a crew from American soil since the shuttles were rolled off to museums.

The tweet was accompanied by a blog post giving SpaceX a nod. The original post was rapidly updated since while Boeing's capsule may have managed just one, near-disastrous flight and SpaceX's spacecraft has survived an exploding Falcon 9 as well as paying an uncrewed visit to the ISS it's still a two-horse race.

The internet, alas for NASA, never forgets.

The tweet was hastily replaced by one that doubtless made faces at Boeing, manufacturers of the Calamity Capsule Starliner CST-100, less frowny.

We imagine that Virgin Galactic, which has already sent Americans into space (depending on which definition you're using), might have had a thing or two to say about that assertion too, though the suborbital lobs in Branson's much delayed glider are quite a bit different to SpaceX and Boeing's orbital ambitions.

While it is over a year since NASA's New Horizons probe made its flypast of the Kuiper Belt Object Arrokoth (formerly known as 2014 MU69), the spacecraft has continued to return to Earth the data it captured during the event. Last week, the team reported more findings, giving new insights into how planetesimals (the building blocks of planets) are formed.

Arrokoth consists of two lobes, and the gang has pieced together a picture of how the object came to be; two objects formed close together and orbited each other at low velocity before gently merging to create the 22-mile long object.

The indications are that Arrokoth formed during the gravity-driven collapse of a cloud of solid particles rather than through hierarchical accretion (the slamming together of planetesimals to form larger bodies).

The probe, now 7.1 billion kilometres from Earth and heading deeper into the Kuiper Belt at nearly 50,400 kilometres per hour, has more observations to transmit, and Principal Investigator for the mission Alan Stern told The Register that it would be 2021 before everything was down.

This summer the team will start searching for more bonus KBOs for the probe to visit, should fuel allow.

Having made much of its lunar ambitions last year, Rocket Lab was cock-a-hoop over its selection by NASA last week for the upcoming Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment (CAPSTONE) mission, which will be launched from the company's Launch Complex 2 at the Wallops Flight Facility in Virginia, USA. The CAPSTONE satellite will be sent on its way by Rocket Lab's Photon platform, eventually operating in a near-rectilinear halo orbit around the Moon.

CAPSTONE will pass as close as 1,000 miles and as far as 43,500 miles from the lunar surface.

The mission is slated for launch in early 2021, and it will take nearly three months for CAPSTONE to enter its target orbit ahead of spending six months demonstrating operations in the region where NASA hopes to send the Lunar Gateway. Should the latter, of course, survive the determination of lawmakers to sacrifice sustainability on the altar of getting flags on footprints on the regolith by 2024.

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SpaceX's next Starlink volley remains stuck on Earth to glee of astronomers everywhere - The Register

Near Earth objects. Credit: ESA P.Carril.

Three Leiden astronomers have shown that some asteroids that are considered harmless for now, can collide with Earth in the future. They did their research with the help of an artificial neural network. The results have been accepted for publication in the journal Astronomy & Astrophysics.

Using a supercomputer, the researchers integrated the orbits of the sun and its planets forward in time for 10,000 years. After that, they traced the orbits back in time while launching asteroids from the Earths surface. During the backwards calculation, they included the asteroids in the simulations in order to study their orbital distributions at todays date. In this way, they acquired a database of hypothetical asteroids for which the researchers knew that they would land on the Earths surface.

Astronomer and simulation expert Simon Portegies Zwart explains: If you rewind the clock, you will see the well-known asteroids land again on Earth. This way, you can make a library of the orbits of asteroids that landed on Earth. The library of asteroids then served as training material for the neural network.

The first set of calculations was performed on the new Leiden super computer ALICE, but the neural network runs on a simple laptop. The researchers call their method Hazardous Object Identifier (HOI), which means hi or hello in Dutch.

The neural network can recognize well-known near-Earth objects. In addition, HOI also identifies a number of hazardous objects that were not previously classified as such. For example, HOI discovered eleven asteroids that, between the years 2131 and 2923, come closer than ten times the Earth-Moon distance and are larger than a hundred meters in diameter.

That these asteroids have not previously been identified as potentially dangerous is because the orbit of these asteroids is so chaotic. As a result, they are not noticed by the current software from space organizations, which is based on probability calculations that use expensive brute force simulations.

According to Portegies Zwart, the research is only a first exercise: We now know that our method works, but we would certainly like to delve deeper in the research with a better neural network and with more input. The tricky part is that small disruptions in the orbit calculations can lead to major changes in the conclusions.

The researchers hope that in the future an artificial neural network can be used to detect potentially hazardous objects. Such a method is much faster than the traditional methods that space organizations use nowadays. By noticing asteroid on a collision course earlier, the researchers say, organizations can sooner think of a strategy to prevent impact.

Reference: Identifying Earth-impacting asteroids using an artificial neural network by John D. Hefele, Francesco Bortolussi and Simon Portegies Zwart, 4 February 2020, Astronomy & Astrophysics.DOI: 10.1051/0004-6361/201935983

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Astronomers Discover Eleven Dangerous Asteroids That Could Impact the Earth - SciTechDaily

In an effort to better understand the loss of the night sky due to light pollution, astronomers are calling on star-lovers and romantics to enjoy a night under the stars and give them a helping hand.

Each year, a group of astronomers, headed by Connie Walker at the National Science Foundation's National Optical-Infrared Astronomy Research Laboratoryin Tucson, Az., conduct the Globe at Night project, whichasks people around the world to step out and record how many stars they see in a specific constellation.

This, in turn, will allow them to gauge how dark or bright the night sky is in a particular location.

This year, the campaign has two runs, the first from Feb. 14 to 23 and the second from March 14 to 24.

"The Globe at Night is a social science program. That means every citizen can be an actual scientist and contribute data. And it's extremely easy to do," said Walker. "People can get involved very simply by just going out in the night, then looking up at the stars."

For Valentine's Day, the particular constellation the project is asking citizen scientists to look at is Orion.

Walker said that the whole process is easy, particularly as Orion is one of the most recognizable constellations in the northern hemisphere this time of year.

Participants are asked to visit the Globe at Night's webapp. It asks the time and date and your location (it can also do this automatically). Then there are seven illustrations to choose from, based on how many stars you saw. And finally, it asks you what the sky conditions were at the time of observation, i.e. partly cloudy, etc.

Walker explained the difference between the charts, which measure the magnitudes or apparent brightness of the star.

"So, one, it's like you would see in New York City, where there's just a couple of stars at best if you see any at all towards Orion," she said. "And thenseven, it's like you're in the national parks, where you see a couple thousand stars."

Most people probably don't think of light as a form of pollution, but it's something that has serious consequences for human health, the environment and wildlife.

For example, light pollution which is simply defined as the "inappropriate or excessive use of light," according to the International Dark-Sky Association (IDA) has affected the nesting habits of sea turtles. There are also estimates that 300,000 to one billion birds die annually from flying into buildings, because they are drawn to the bright lights at night.

As for humans, some studies have linked artificial light with forms of cancer.

About 54 per cent of people around the world live in cities. In Canada, that number soars to more than 80 per cent. As a consequence,most people across the planet have not seen the Milky Way.

Though many people and communities have switched to energy-saving LED lights, a 2017 study by Canadian Christopher Kyba, a light pollution researcher at the GFZ German Research Centre for Geosciences, found that these lights might actually be doing more harm than good.

Because the lights cost less, it appears more of them are being used. Kyba, who is involved in the Globe at Night project,is looking to conduct follow-up studies to determine if the night sky brightness is increasing or decreasing.

But why does it matter if we see the stars or not?

"It's part of our cultural heritage. It has inspired humanity, since the beginning of humanity, for tens of thousands of years. It is an infinite resource for wonder, and it's where all of our thoughts about science began," Walker said. "And it's not just science. It's the inspiration to be creative in terms of music, like [Gustav] Holst's The Planets,or literature like Shakespeare .... and then paintings, likeVan Gogh.

"If we take away that source of inspiration. What is it going to do to our culture?"

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Astronomers want you to help them count the stars this Valentine's Day - CBC.ca

Stargazing scientists have recently begun to focus on the prospect of encountering intelligent extraterrestrials, and the more they think about it the more they realize the first meeting probably wont be with little green men in flying saucers.

What aliens might look like is a growing question among astrobiologists, who are increasingly conjuring up creatures more Lilliputian than mega-brained or reptilian.

The intriguing possibility is they are, in fact, here, but we just dont know it, said Andrew Fraknoi, the emeritus chairman of the astronomy department at Foothill College who recently taught a course on aliens at the University of San Franciscos Fromm Institute and believes space aliens could very well be microscopic or unrecognizable as a life-form.

Fraknoi is on the board of the Search for Extraterrestrial Intelligence, known as the SETI Institute, based in Mountain View, where questions about alien civilizations are often discussed. He has long speculated that members of a civilization billions of years old might by now have evolved into a mechanical-biological mix, like a robot with a brain, capable of living for thousands of years as they travel through space.

But it is also possible, he said, that advanced civilizations would have sent into space thousands of tiny canisters holding the germs of life programmed to incubate and grow when they encounter suitable conditions around a star.

In all the mathematical models, a species that started early in the history of the galaxy and had the will and resources to diffuse could by now have filled many parts of the galaxy with its artifacts or biological spores, Fraknoi said.

The otherworldly speculation comes after the recent discovery of two interstellar objects zipping past Earth prompted a surge of interest among scientists in space travel and alien civilizations.

A spinning, red, cigar-shaped object called 1I/Oumuamua was spotted in 2017, followed by the sighting last year of a comet named 2I/Borisov. They were the first verified sightings in human history of objects speeding by from outside our solar system.

The objects, by their very existence, brought home to many astronomers the reality that rocks or vessels potentially carrying biological spores from other solar systems could actually reach Earth.

The notion got a major boost from Avi Loeb, the chair of Harvard Universitys astronomy department. He co-wrote a scientific paper suggesting that Oumuamuas odd, elongated shape and peculiar nongravitational acceleration could mean it is a mechanical probe a light sail driven by sunshine sent by an alien civilization.

The object, first spotted by the University of Hawaiis Institute for Astronomy, was, by all accounts, strange. Observations from Earth as it shot past the sun on Sept. 9, 2017, at a speed of 196,000 mph showed that it was slowly spinning, like a bottle on its side, and that it was missing the tail of gas or dust that would signify a comet.

Astronomers around the world immediately attacked Loebs hypothesis, and a subsequent study published in Nature Astronomy last year concluded that Oumuamua was a rocky conglomeration, not a space ship.

But Loeb said his point was that objects like Oumuamua and Borisov could have been synthetic and that humans would be well served by developing techniques for determining if such visitors were constructed. He believes the possibility of extraterrestrial life is too important for humans to discount without investigation, especially considering how useful it would be in figuring out the origin of life.

Intelligent life is more recent in the Earths history, but at the same time, given that it happened here, there is the possibility that it exists elsewhere, Loeb said. I dont think we should pretend that we are the only ones the smartest kid on the block because very likely we arent the smartest kid on the block.

The questions about what form alien beings might take are rooted in what is known as the Fermi paradox, named after Italian American physicist Enrico Fermi, who created the first nuclear reactor. He asked during a casual lunchtime conversation in 1950 why aliens have never been spotted, given the high probability of their existence.

SETI has been searching the skies for radio signals or some other sign of life beyond Earth for nearly four decades without a single peep.

Despite the failure, belief in the existence of extraterrestrial civilizations has only increased since Fermis time. Thats largely because powerful telescopes have recently detected numerous planets orbiting their stars at a habitable distance, known as the Goldilocks zone. Calculations indicate there are habitable planets around at least a quarter of the tens of billions of stars in the Milky Way Galaxy, possibly including the closest star, Proxima Centauri, 4.2 light-years from Earth.

Most astrophysicists believe life must have sprung up somewhere, some time, in the 13.5 billion years since the galaxy was formed. Given that our sun is 4.6 billion years old, Fraknoi said civilizations in other parts of the galaxy could have been using robotics, artificial intelligence and tapping the energy from their stars as many as 8 billion years before our solar system was created.

In other words, Fraknoi said, there has been ample time for a civilization to become advanced enough to send alien microbes or micro-artifacts around the galaxy, including to our solar system.

Astronomers have even concocted a sciency name, directed panspermia, to describe the act by an alien civilization of planting the seeds of life in another world.

Samantha Rolfe, a lecturer in astrobiology at Bayfordbury Observatory at the University of Hertfordshire in England, suggested recently that such organisms could be hidden inside what she called a microscopic shadow biosphere that is so different from ours that we dont even recognize it as biological in origin.

So why havent we found it? We have limited ways of studying the microscopic world as only a small percentage of microbes can be cultured in a lab, she wrote in an article for the Conversation website. We do now have the ability to sequence the DNA of unculturable strains of microbes, but this can only detect life as we know it that contain DNA.

Some have suggested that these alien life-forms could be small inactive spores floating in our solar system waiting for the right conditions to grow or as active monitors transmitters used by alien civilizations to determine whether Earthlings are a threat and might need to be eliminated.

Then again, a growing number of astronomers speculate that humanity itself might have originated somewhere else, possibly clinging to a chunk of rock ejected from a planet that was hit by a giant meteor.

We know there are rocks on Earth that came from Mars, so you could imagine that microbes could have potentially survived the journey, Loeb said. So its possible we are all Martians. If you can do it from Mars, you can potentially bring life from other planets in other galaxies.

Loeb recently published a paper calculating how asteroids could graze Earths atmosphere, scoop up microbes like the foamy cream off a latte, and potentially carry the seeds of life into outer space. Maybe, he and others suggest, this swapping of biological spores has happened since the beginning of time.

Either way, most experts believe an alien encounter is likely someday. The question, say those who think about such things, is whether humans will know it when they see it.

Potentially, we could be part of an experiment where life was planted on Earth and someone is watching, Loeb said. If thats the case, for sure they are disappointed. That would be my assessment by reading the morning newspaper.

Peter Fimrite is a San Francisco Chronicle staff writer. Email: pfimrite@sfchronicle.com Twitter: @pfimrite

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Scientists theorize that space aliens may already be here, but we dont recognize them - San Francisco Chronicle

Later Jaina mathematicians, Dharamanandana and Sundarasuri, continued explorations on magic squares and similar arrangements.

But from the fourteenth century, Kerala became the locus of several new siddhaantas, bhaashyas, karanas etc., that it is now called the Kerala school of mathematics.

The Kerala school

Shortly after Aryabhata, a mathematician called Haridatta had composed a work title Parahita Ganita based on Aryabhatiyam. After that we seem to have a vacuum in Kerala until Madhava (c 1340 AD) of Sangamagrama (Kudalur in Malayalam). What followed is an astonishing continuity of the guru-shishya parampara from Govinda Bhattatiri to Rajaraja Varma.

Madhava was famous as a skilled instrument maker. Indian historians of mathematics consider him the pitamaha of the Kerala school. Perhaps, his most famous contribution is sums of infinite series.

To calculate the circumference (paridhi) of a circle, said Madhava, we must multiply the diameter (vyaasa) by four times one minus tri-sharaa-aadi-vishama-samkhyaa-bhaktam-rNam. A phrase of compactness, which Aryabhata would have enjoyed. In other words, a sequence of odd (vishama samkhyaa) denominators (bhaktam) starting (aadi) with three (tri) and five (sharaa). The word sharaa here is a bhutasamkhya (see third essay) word for the five arrows of Manmatha, whose archery takes precedence over Rama and Arjuna and even Tripurantaka, in this case.

The sum of the series in the brackets adds up to /4, and is famous as the Gregory Leibniz series.

Madhavas series was quoted and a proof (upapatti) also given a century later by Jyeshtadeva.

Parameshvara Like Brahmagupta providing a sphuTam to Paitamaha Siddhaanta, Parameshvara observed that over time, predictions of earlier astronomers did not agree with observed positions based on calculations. In such a situation, he observed, one must adjust ones methods and calculations, because planets and stars will conform to them.

He titled his book Drg Ganitam. This title, which means Observed Calculations, is a popular phrase for jyotisham in south India, though the author himself has faded from public memory. His shishya NilakanTha referred to him as Paschimaam Bodhi, the western scholar.

Nilakantha Somayaaji More unknown than even Brahmagupta, was a polymath like Varahamihira. He was a scholar of Shad darshana (the six philosophies of Hinduism, and also in vyaakarana, chandas, the Bhagavata and various such literature. He also studied Vedanga Jyotisha, Pancha Siddhaantika, Brhat Samhita etc.

This historical curiosity and scholarship may have shined in other scholars, too, but in Nilakantha, we have contemporary evidence. He was also a prolific composer, of several texts.

He was a friend a Sundararaja, a jyotisha of the neighboring Tamil Nadu, and took the effort to compile a written list of answers for questions posed by the former, compiled into a book called Sundararaja Prashnottara.

Aficionados of European science may be reminded of the extensive correspondence of Franklin, Newton, Darwin, Humboldt etc.

A ninth century mathematician called Virasena in his commentary Dhavala gave this equation, that the sum of all powers of 1/4 is 1/3. One sees the reflection of this in Madhavas several infinite series. Nilakantha questioned this apparent absurdity. How does the sum of this infinite series increase to that finite value (1/3), and that it reaches finite value?

He reasoned and explained it by deriving the following sequence of results

As we add more terms, argued Nilakantha, the difference between 1/3 and the powers of 1/4 become extremely small, but never zero, unless we add terms up to infinity. In the 20th century, Ramanujan revelled in such series.

Quasi Heliocentric theory NilakanThas questioning of an assumption of planets latitudes (vikshepa), and his subsequent discovery was truly astronomical (pardon the pun). From the siddhantas through Bhaskaracharya, all astronomers used a slightly different method to calculate the latitudes of Mercury (Budha) and Venus (Shukra), than they did for the other planets. This niggled most of them, as inappropriate, especially Bhaskara, who then consoled himself with Prthudaka Svamis explanation.

But NilakanTha questioned this acceptance, and modified his computation, and effectively the orbital model for these planets. He came to the conclusion that these two planets revolve around the Sun (but in his model, the Sun still revolves around the Earth).

The geometrical argument is too complicated not only for this article, but even, perhaps, for those who are not astronomers, so I will only present a visual illustration of his model here.

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Indian Astronomy And Mathematics: When Kerala Became The Locus Of Genius - Swarajya

Using data from the Atacama Large Millimeter/submillimeter Array (ALMA), a team of Japanese researchers has found that Galactic cosmic rays affect the chemical reactions involved in the formation of nitrogen-bearing organic molecules in the atmosphere of Titan, the largest moon of Saturn.

This view of Titan is among the last images NASAs Cassini spacecraft sent to Earth before it plunged into the giant planets atmosphere. Image credit: NASA / JPL-Caltech / Space Science Institute.

Titan is a carbon-rich, oxygen-poor world with a wide range of organic and inorganic compounds, atmospheric energy sources, and liquid hydrocarbon seas and lakes.

This moon is the only planetary body in the Solar System, except Earth, where rainfall and seasonally flowing liquids erode the landscape.

In addition to a hazy mixture of nitrogen and hydrocarbons like methane and ethane, the atmosphere of this strangely Earth-like world also contains an array of more complex organic molecules.

Planetary scientists think that this chemical make-up is similar to Earths primordial atmosphere.

In a new study, University of Tokyos Dr. Takahiro Iino and colleagues used ALMA to study the chemical processes in Titans atmosphere.

The researchers detected faint but firm signals of two organic compounds acetonitrile (CH3CN) and its rare isotopomer CH3C15N in the ALMA data.

We found that the abundance of 14N in acetonitrile is higher than those in other nitrogen bearing species such as HCN and HC3N, Dr. Iino said.

It well matches the recent computer simulation of chemical processes with high energy cosmic rays.

There are two important players in the chemical processes of the atmosphere: ultraviolet (UV) light from the Sun and cosmic rays from beyond the Solar System.

In the upper atmosphere, UV light selectively destroys nitrogen molecules containing 15N because the UV light with the specific wavelength that interacts with 14N is easily absorbed at that altitude, the study authors explained.

Thus, nitrogen-bearing species produced at that altitude tend to exhibit a high abundance of 15N.

On the other hand, cosmic rays penetrate deeper and interact with nitrogen molecules containing 14N.

As a result, there is a difference in the abundance of molecules with 14N and 15N.

The team revealed that acetonitrile in the stratosphere is more abundant in 14N than those of other previously measured nitrogen-bearing molecules.

We suppose that galactic cosmic rays play an important role in the atmospheres of other solar system bodies, said Dr. Hideo Sagawa, a researcher at Kyoto Sangyo University.

The process could be universal, so understanding the role of cosmic rays in Titan is crucial in overall planetary science.

A paper on the findings will be published in the Astrophysical Journal.

_____

Takahiro Iino et al. 2020. 14N/15N isotopic ratio in CH3CN of Titans atmosphere measured with ALMA. ApJ, in press; arXiv: 2001.01484

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Cosmic Rays from beyond Solar System Affect Atmosphere of Titan | Astronomy - Sci-News.com