Category Archives: Astronomy

The Tumult of the Sun Hassan Hatami

From a turbulent image of our star and an odd-looking Martian sunset to the mesmerizing Dolphin Head Nebula and a close-up of the International Space Station set against the Moon, the Royal Observatorys annualAstronomy Photographer of the Year competition has once again produced some astonishing images of our Solar System and of the deep sky.

Run by the Royal Observatory Greenwich in London in association withBBC Sky at Night Magazine and now in its thirteenth year, the competition this year received over 4,500 entries from around the world.

Here are eight of the Solar System and deep sky entries from Iran, Sri Lanka, China and even from the Martian surface, some of which will triumph and feature in the final 11 when the results are announced in September 2021.

Above: Using a specially selected image from NASAs Solar Dynamics Observatory collection, photographer Hassan Hatami from Iran used a combination of three wavelengths to create this image of the turbulent Sun.

The original images were taken by the SDO in January 2015 when our Sun was close to solar maximum.

Dolphin Head Nebula Yovin Yahathugoda

Above: interstellar winds create a perfect cosmic bubble in this bi-colour image of the Dolphin Head Nebula in the constellation Canis Major, the Big Dog. At the center of the image is a rare Wolf-Rayet star.

It took the photographer 1.5 hours exposure time over three nights to capture this image using a remote telescope in Chile.

Saturn at its Best Damian Peach

Above: ace planetary astrophotographer Damian Peach here shows-off an image of the ringed planet taken from La Palma, Murcia, Spain in July 2020.

Its polar hexagon can be seen around the pole at bottom, while many other belts and zones can be seen across the planet.

Martian Sunset John White

Above: When NASAs Mars Curiosity Rover captures images it dumps them on a server thats publicly available. Photographer John White searched over 390,000 images in the Mars Curiosity raw archive and found these four that show a sunset on the Red Planet.

Why is it blue? Unlike on Earth, blue light better penetrates the fine dust in the Martian atmosphere. The images were taken in April 2015.

A Daytime Transit Andrew McCarthy

Above: the International Space Station (ISS) transiting a slim waning crescent Moon during daylight. Shot in Elk Grove, California in October 2020, this ISS transit of the Moon was captured using two cameras and two telescopes.

The Rose Josep Drudis

Above: the Ring Nebula (M57) is the glowing remains of a Sun-like star and a very famous planetary nebula previously photographed by the Hubble Space Telescope, but its rarely looked like this before. Taken with a professional Planewave CDK24 telescope in the near infra-red, you can see its faint halo as a collection of petals.

This image was taken with hydrogen (red) and oxygen (green and blue) filters, but also adding nitrogen (deep red). Taken from Mayhill, New Mexico, USA, during April, May and June 2020.

Pleiades Sisters Jashanpreet Singh Dingra

Above: Heres a gorgeous image taken in December 2020 from Patiala, Punjab, India by 14-year old Jashanpreet Singh Dingra. The Pleiadesalso known as the Seven Sisters and M45is an open star cluster containing middle-aged, hot B-type stars in constellation of Taurus, the Bull. The closest open cluster to the Solar System, the Pleiades is easy to see naked-eye.

Here the photographer has used a Takahashi FSQ-85ED telescope to reveal its nebulositythe hot gas between the stars and illuminated by themover the course of three hours of exposures.

NGC 3981 Bernard Miller

Above: The windswept NGC 3981 is a spiral galaxy about 65 million light years away in the constellation of Crater. Taken using a remote telescope in Chile in February 2021 over 34 hours.

Wishing you wide eyes and clear skies.

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In Photos: Angry Sun, A Blue Martian Sunset And Weird Dolphin Head Star In Astronomy Photographer Of The Year Entries - Forbes

A clash among members of a famous galaxy quintet reveals an assortment of stars across a wide color range, from young, blue stars to aging, red stars. Ancient Greek astronomers paved the way for our modern understanding of the heavens. Credit: NASAandESA Public Domain

Business moguls Sir Richard Branson and Jeff Bezos should be thanking ancient Greek astronomers for being able to realize their travel off the face of the earth and into space this month. Virgin Galactics Branson hopes to beat Amazon CEO Bezos to travel to space, announcing plans to be Astronaut 001 on the firms July 11 test flight.

As civilized societies were just learning to use the wheel on earth, the ancient Greeks were aiming at the sky and the stars, contemplating outer space and how to measure it.

Even the science of the study of the sky and the stars, astronomy, finds its root in the ancient Greek wordAstronomia.

It was under Greek skies that ancient astronomers began to develop theories about the planets overhead, theories that are now proven. Christopher Columbus may or may not have set out to prove that the earth was spherical, but it was the ancient Greek astronomer Aristarchus who initiated the theory that the universe is heliocentric and that the planets are round.

The Babylonians of Mesopotamia first looked to the skies and postulated that the stars, the moon and the sun as gods that ruled over men. However, it was the ancient Greeks who analyzed those theories of deities and turned them into mathematical equations and calculations.

If you really want to travel to the stars, there is an easier way than heading to Cape Canaveral, where NASA launches rockets from Florida into outer space, or getting an extraordinarily pricey ticket aboard the craft that Branson and Bezos will travel on this month.

If you can get to the Acropolis, just a few hundred meters away is the National Observatory, known in Greece as the Asteroskopeio. From the observatory, positioned directly across from the Acropolis on Lofos Nymphon in central Athens, you can get a birds eye view of Mars and the moon through the Doridis refractor telescope.

The National Observatory with a telescope that allows the public to view the stars directly across from the Acropolis. Credit: Dimboukas Creative CommonsAttribution 4.0 International

The National Observatory of Athens was founded in 1842, as the first research center of modern Greece. Its history is linked with the evolution of basic and applied research, the development of services provided to the Greek State and society at large, and the promotion of science.

And how amazing is it, that literally just steps away from where ancient Greek astronomers conducted their first experiments, contemporary Greek astronomers are working today and they can show you the planets in the night sky?

Metonas was a Greek mathematician, astronomer and engineer who lived in Athens in the 5th century BC. He is best known for the calculations he made for the Metonic cycle in 432 BC for the lunar calendar year of Attica.

Metonas calendar assumes that 19 solar years equals 235 lunar months, which equals 6,940 days. This system arose from calculations made by Metonas based on his own astronomical observations, which were confirmed by Aristarchus 152 years later.

According to the testimonies of ancient historians, Metonas installed the first Heliotropion, or Helioscope, in Pynx, a hellion Athens. The foundations of the Helioscope are still visible just behind the steps leading to Pnyx, the archaeological site perched on a small, rocky hill, just over 330 feet high in the center of Athens.

The site is in a large park, just below the National Observatory, to the west of the Acropolis. Metonas determined the dates of the equinoxes and the solstices based on the specific location of this helioscope.

From this position the sunrise during the summer solstice is seen from the top of Mt. Lycabettus, while six months later, during the winter solstice, the sun rises from the top of Mount Hymettus. The annual apparent movement of the sun on the horizon creates an arc of 60 degrees, the bisector of which is aligned with the rock of the Acropolis. The exact determination of the summer solstice was important to the ancient Athenians because the first moon, after the summer solstice, marked the beginning of the new year.

Metonas was one of many ancient Greek astronomers to formulate calculations while gazing at the skies above. Renowned mathematicians, many of these scholars, branched off in astronomy, cataloguing, calculating and observing. Whether they catalogued stars, contemplated shapes or tried to measure the physical space within and beyond the borders of earth, their work put contemporary man in the sky.

Today it is hard to believe in any other notion than spherical planets that revolve around the sun.

Pythagoras of Samos, who lived from 570 to 495 BC, was an ancient Greek astronomer and philosopher and the eponymous founder of Pythagoreanism. Pythagoras was credited with many mathematical and scientific discoveries in antiquity. Since at least the first century BC, Pythagoras has commonly been given credit for discovering the Pythagorean theorem in geometry, which states that in a right-angled triangle the square of the hypotenuse is equal (to the sum of) the squares of the two other sides.

It was said that he was the first man to call himself a philosopher, a lover of wisdom, in the Greek language, (philo/friend of sophia/wisdom). He was the first to divide the globe into five climatic zones.

In astronomy Pythagoras is credited with the belief that the earth is spherical and for identifying the morning and evening stars that we know today as the planet Venus. By the end of the fifth century BC, this fact was universally accepted among Greek intellectuals.

Philolaus, who lived from 470 to 385 BC, was a Greek Pythagorean and pre-Socratic philosopher. He was born in a Greek colony in Italy and migrated to Greece. Philolaus has been called one of three most prominent figures in the Pythagorean tradition and the most outstanding figure in the Pythagorean school.

Pythagoras developed a school of philosophy that was dominated by both mathematics and mysticism. Most of what is known today about the Pythagorean astronomical system is derived from Philolaus views. He may have been the first to write about Pythagorean doctrine.

Philolaus asserted that the earth was not the center of the universe, rebelling against the geo-centrism of the time. He is credited with the earliest known discussion of concepts in the development of heliocentrism, insisting the sun is the center of in the human universe.

Archimedes of Syracuse, who lived from 287 to 212 BC, was an ancient Greek astronomer, mathematician, physicist, engineer, inventor, and astronomer. Although few details of his life are known, he is regarded as one of the leading scientists of classical antiquity. The most widely known anecdote about Archimedes tells of how he invented a method for determining the volume of an object with an irregular shape.

Archimedes principle involved a metal bar, placed into a container of water, on a scale. It displaces as much water as its own volume, increasing the mass of the containers contents and weighing down the scale.

A votive crown for a temple had been made for the king of Syracuse, who had supplied the pure gold to be used. Archimedes was asked to determine whether some silver had been substituted by a dishonest goldsmith. Archimedes had to solve the problem without damaging the crown, so he could not melt it down into a regularly shaped body to calculate its density.

Archimedes noticed while taking a bath that the level of the water in the tub rose as he got in. He realized that this effect could be used to determine the volume of the crown. For practical purposes, water is incompressible so the submerged crown would displace an amount of water equal to its own volume.

By dividing the mass of the crown by the volume of water displaced, the density of the crown could be obtained. This density would be lower than that of gold if cheaper and less dense metals had been added. Archimedes then took to the streets naked, so excited by his discovery that he had forgotten to dress himself, crying Eureka, which in Greek sounds like evreeka, literally meaning, I have found it!

The test on the crown was conducted successfully, proving that silver had indeed been mixed in with the gold.

Archimedes also explored astronomical measurements of the earth, the sun and the moon, as well as Aristarchus heliocentric model of the universe. Despite a lack of trigonometry and a table of chords, Archimedes described the procedure and instrument used to make observations, a straight rod with pegs or grooves, applied correction factors to these measurements, and finally gave the result in the form of upper and lower bounds to account for observational error.

Ptolemy, quoting Hipparchus, also references Archimedes solstice observations in the Almagest. This would make Archimedes the first known ancient Greek astronomer to have recorded multiple solstice dates and times in successive years.

Ptolemy, 335-405 BC, used an astrolabe to record astronomical observations.

Today we know the exact time, the positions to the stars and planets, and our exact location, to the tenth of a degree but all these things were available to the ancient Greeks as well, in one device, thanks to the invention of the astrolabe.

The scientistPtolemy, who lived in Alexandria, was the brilliant mind behind this genius machine, which used sets of dials to determine altitude, latitude as long as the time was known the shifting positions of stars and planets, and to survey or triangulate your location on land.

Basically, the astrolabe was a handheld model of the universe. Its many functions also made it an elaborate inclinometer and an analog calculation device that was capable of working out several kinds of problems in astronomy.

The importance of the invention of the astrolabe comes not only from the early discoveries in astronomy, but also in determining latitude on land or on calm water, making it possible to navigate the seas in a limited way.

Aristarchus of Samos,who lived from 310 to c.230 BC, was an ancient Greek astronomer and mathematician who presented the first known heliocentric model that placed the sun at the center of the known universe, with the earth revolving around the sun once a year and rotating about its axis once a day. Aristarchus identified the central fire with the sun. He put the other planets in their correct order of distance around the sun.

Aristarchus suspected that the stars were just other bodies like the sun, albeit farther away from earth. His astronomical ideas were rejected in favor of the geocentric theories of Aristotle and Ptolemy.

Aristarchus estimated the sizes of the sun and moon as compared to earths size. He also estimated the distances from the earth to the sun and moon. He is considered one of the greatest astronomers of antiquity.

Aristarchus of Samos developed the first mathematical formula of astronomy to calculate planet size. Credit: Screenshot Youtube

Since Aristarchus suspected the stars were other suns that are very far away, there was no observable parallax that is, a movement of the stars relative to each other as the earth moves around the sun. Since stellar parallax is only detectable with telescopes, his accurate speculation was unprovable at the time.

It was not until the sixteenth century that a mathematical model of a heliocentric system was presented by the Renaissance mathematician, astronomer, and Catholic cleric, Nicolaus Copernicus, leading to the Copernican Revolution. In the following century, Johannes Kepler introduced elliptical orbits, and Galileo de Galilei presented supporting observations made using a telescope.

Eratosthenes of Cyrene, who lived from 276 BC to195 BC, was an ancient Greek astronomer who was also a multi-discipline scholar, or polymath. He was a mathematician, geographer, poet, astronomer and music theorist. He was a man of such learning that he also became the chief librarian at the Library of Alexandria. His work is comparable to what is now known as the study of geography, and he introduced some of the terminology still used in that discipline today.

Eratosthenes is best known for being the first person known to calculate the circumference of the earth, which he did by using the extensive survey results he could access in his role at the Library of Alexandria. His calculation was remarkably accurate. He was also the first to calculate earths axial tilt, which also proved to have remarkable accuracy. He created the first global projection of the world, incorporating parallels and meridians based on the available geographic knowledge of his era.

Eratosthenes was the founder of scientific chronology. He endeavored to revise the dates of the main events of the semi-mythological Trojan War, dating the Sack of Troy to 1183 BC. In number theory, he introduced the sieve of Eratosthenes, an efficient method of identifying prime numbers.

The measurement of Earths circumference is the most famous among the results obtained by Eratosthenes, who estimated that the meridian has a length of 252,000 stadia, with an error on the real value of less than two percent. Eratosthenes described his arc measurement technique, in a book entitled On the measure of the Earth.

Hipparchus of Nicaea, 190120 BC, yet another ancient Greek astronomer, erected an early observatory on the island of Rhodes around 150 BC, and set about compiling a star catalogue with approximately 850 entries. He calculated the celestial coordinates for each star using the first known trigonometric table, and developed and improved several astronomical instruments, including the astrolabe.

Dedicated to Hipparchus contribution to the early study of the solar system, a crater on the surface of Mars, was named after him in 1973. A larger crater on the moon was also named after the ancient Greek astronomer.

The Antikythera Mechanism,often referred to as the worlds first computer, was discovered inside an ancient shipwreck by Greek sponge divers on May 17, 1901. After numerous studies, it was estimated to have been constructed between 150 BC and 100 BC.A later study places it at 205 BC,just seven years after the death of Archimedes.

The worlds oldest surviving mechanical calculator, it was used by ancient Greek astronomers. The device has now been somewhat deteriorated by the passage of time, but when intact it would have appeared as a box, housing dozens of finely machined bronze gear wheels.

When manually rotated by a handle, the gears spun dials on the exterior showing the phases of the moon, the timing of lunar eclipses, and the positions of the five planets then known (Mercury, Venus, Mars, Jupiter, and Saturn) at different times of the year. This even accounted for their retrograde motion an illusionary change in the movement of planets through the sky.

The moving parts of a a reproduction of the Antikythera Mechanism, an ancient analog computer. Credit: Freeth, T., Higgon, D., Dacanalis Creative CommonsAttribution 4.0 International

It may even have been the work of Archimedes himself, but there is no documentation of that, only speculation. Gearing technology with the sophistication of the Antikythera Mechanism was not seen again for one thousand years.

The ancient calculator also includes an astrological calendar, as the indicators seem to revolve around the zodiac, revealing the movements of both the moon and the planets.

A reproduction of the Antikythera Mechanism on display at the National Observatory in Athens. Credit: Moravec Creative CommonsAttribution-Share Alike 4.0 International

The National Observatory is the contemporary location for a journey to the stars. As noted above, the Asteroskopeio is within close proximity to the physical space used by ancient Greek astronomers who contributed so much to what we know of the universe today.

Ancient Greek astronomers such as Metonas, Pythagoras, Philolaus, Eratosthenes, Ptolemy, Aristarchus, Hipparchus, Archimedes developed the theories of calculation of the size, the time and the distance of planets within the human solar system. These contributions were the building blocks that made journeys off earth possible today.

Progress was marked by enlightened and renowned scientists in Greece who paved the way to knowledge with the creation of the Asteroskopeio in the 1800s. Thanks to the National Observatory, visitors to Athens can travel to the stars even if they are not Richard Branson or Jeff Bezos.

The tycoon Branson said, After more than 16 years of research, engineering, and testing, Virgin Galactic stands at the vanguard of a new commercial space industry, which is set to open space to humankind and change the world for good.

Lets hope he remembers to thank all those ancient Greek astronomers and not just the people who work for Virgin Galactic.

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Ancient Greek Astronomers -- And Modern Moguls -- Aim for the Stars - Greek Reporter

In the early 1900s, the universe seemed to be a much, much smaller place. Back then, astronomers believed the Milky Way galaxy was all there was. They didnt know there were billions of other galaxies; they didnt know how small we really are.

They didnt know this because they couldnt measure distances to far-flung stars. Why? There was a pretty simple problem in astronomy: A bright, faraway star looks almost the same as a dim star thats close by.

Its the same here on Earth. Imagine youre on the beach at night and see two lighthouse lights glowing in the distance, but one seems brighter than the other. If you knew both lighthouses used the same lightbulb, you could conclude that the dimmer light is farther away. But its also possible that the dimmer light just comes from a lower-wattage lightbulb, perhaps nearer to you.

Scientists needed a way to find out the intrinsic brightness of stars to figure out their wattage, so to speak. Thats when Henrietta Leavitt, a Massachusetts-born computer who worked at the Harvard College Observatory, came along. In 1908, she published a discovery that may sound small but is one of the most important in the history of astronomy. It cracked open the universe.

Before Henrietta Leavitt, many astronomers looked at the stars in whats today known as the Andromeda galaxy some 2.5 million light-years away and mistakenly thought they were part of our own Milky Way galaxy (which is only around 100,000 light-years in diameter).

Those Andromeda stars were orders of magnitude further away. Scientists just didnt know it.

At the time, astronomers had some methods to figure out distances to stars, but they only worked for stars relatively close to Earth. Leavitts discovery linking the pulse of one type of star to their actual brightness, as described in the graphic above was the key to measuring objects farther and farther out into space.

If astronomers wanted to measure faraway things, Leavitts discovery showed, they just had to look out for cepheids. Her formula led astronomers to chart out relative distances to stars: They could use it to compare two stars and figure out which one was closer.

It took some more work by other scientists to calibrate this yardstick, to put concrete numbers on it. But once they did, and started measuring with it, the cosmos grew and grew.

Fifteen years after Henrietta Leavitts discovery, the preeminent astronomers Harlow Shapley and Heber Curtis were locked in a heated debate.

Curtis believed that Andromeda was a separate galaxy far, far away from the Milky Way. At the time, this was an outlandish idea. Shapley represented the more mainstream view that Andromeda was just a hazy, cloudy region within our galaxy, which he had recently estimated to be around 300,000 light-years across. That was also the assumed size of the entire universe.

If Curtis was right, it would mean the universe was double or triple the size that Shapley estimated at least.

To settle the debate, Edwin Hubble the namesake of the famous space telescope looked for Cepheid stars in Andromeda. Night after night, he took photographs of Andromeda, searching for cepheids. In October 1923, he found one, blinking in one of Andromedas spiral arms. Another week of observations allowed him to follow Leavitts formula and determine its distance.

Hubble estimated it to be around a million light-years from Earth well outside the boundaries of Shapleys universe. (Hubble was a little off: Andromeda is closer to 2.5 million light-years away.) After reading about Hubbles finding, Shapley reportedly said: Here is the letter that destroyed my universe.

Scientists kept building on Leavitts ruler to measure the universe. And as they used these measuring tools, their understanding of the universe evolved. They realized it was far bigger than previously thought, there are billions of galaxies, and its expanding: Those galaxies are moving further and further away from one another.

Astronomers also realized that the universe had a beginning. If galaxies are moving away from one another now, it means they were closer together in the past which led scientists to the idea of the Big Bang.

It also led them to realize that the universe may, eventually, end.

This weeks episode of Unexplainable, Voxs podcast about unanswered questions in science, tells that story and more.

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How big is the universe? Henrietta Leavitt led Edwin Hubble to a better, bigger answer. - Vox.com

This illustration depicts a planet partially hidden in the glare of its host star and a nearby companion star. After examining a number of binary stars, astronomers have concluded that Earth-sized planets in many two-star systems might be going unnoticed by transit searches, which look for changes in the light from a star when a planet passes in front of it. The light from the second star makes it more difficult to detect the changes in the host stars light when the planet passes in front of it. Credit: International Gemini Observatory/NOIRLab/NSF/AURA/J. da Silva

Astronomers studying stellar pairs uncover evidence that there could be many more Earth-sized planets than previously thought.

Some exoplanet searches could be missing nearly half of the Earth-sized planets around other stars. New findings from a team using the international Gemini Observatory and the WIYN 3.5-meter Telescope at Kitt Peak National Observatory suggest that Earth-sized worlds could be lurking undiscovered in binary star systems, hidden in the glare of their parent stars. As roughly half of all stars are in binary systems, this means that astronomers could be missing many Earth-sized worlds.

Earth-sized planets may be much more common than previously realized. Astronomers working at NASA Ames Research Center have used the twin telescopes of the international Gemini Observatory, a Program of NSFs NOIRLab, to determine that many planet-hosting stars identified by NASAs TESS exoplanet-hunting mission[1] are actually pairs of stars known as binary stars where the planets orbit one of the stars in the pair. After examining these binary stars, the team has concluded that Earth-sized planets in many two-star systems might be going unnoticed by transit searches like TESSs, which look for changes in the light from a star when a planet passes in front of it.[2] The light from the second star makes it more difficult to detect the changes in the host stars light when the planet transits.

The team started out by trying to determine whether some of the exoplanet host stars identified with TESS were actually unknown binary stars. Physical pairs of stars that are close together can be mistaken for single stars unless they are observed at extremely high resolution. So the team turned to both Gemini telescopes to inspect a sample of exoplanet host stars in painstaking detail. Using a technique called speckle imaging,[3] the astronomers set out to see whether they could spot undiscovered stellar companions.

Using the `Alopeke and Zorro instruments on the Gemini North and South telescopes in Chile and Hawaii, respectively,[4] the team observed hundreds of nearby stars that TESS had identified as potential exoplanet hosts. They discovered that 73 of these stars are really binary star systems that had appeared as single points of light until observed at higher resolution with Gemini. With the Gemini Observatorys 8.1-meter telescopes, we obtained extremely high-resolution images of exoplanet host stars and detected stellar companions at very small separations, said Katie Lester of NASAs Ames Research Center, who led this work.

Lesters team also studied an additional 18 binary stars previously found among the TESS exoplanet hosts using the NN-EXPLORE Exoplanet and Stellar Speckle Imager (NESSI) on the WIYN 3.5-meter Telescope at Kitt Peak National Observatory, also a Program of NSFs NOIRLab.

After identifying the binary stars, the team compared the sizes of the detected planets in the binary star systems to those in single-star systems. They realized that the TESS spacecraft found both large and small exoplanets orbiting single stars, but only large planets in binary systems.

These results imply that a population of Earth-sized planets could be lurking in binary systems and going undetected using the transit method employed by TESS and many other planet-hunting telescopes. Some scientists had suspected that transit searches might be missing small planets in binary systems, but the new study provides observational support to back it up and shows which sizes of exoplanets are affected.[5]

We have shown that it is more difficult to find Earth-sized planets in binary systems because small planets get lost in the glare of their two parent stars, Lester stated. Their transits are filled in by the light from the companion star, added Steve Howell of NASAs Ames Research Center, who leads the speckle imaging effort and was involved in this research.

Since roughly 50% of stars are in binary systems, we could be missing the discovery of and the chance to study a lot of Earth-like planets, Lester concluded.

The possibility of these missing worlds means that astronomers will need to use a variety of observational techniques before concluding that a given binary star system has no Earth-like planets. Astronomers need to know whether a star is single or binary before they claim that no small planets exist in that system, explained Lester. If its single, then you could say that no small planets exist. But if the host is in a binary, you wouldnt know whether a small planet is hidden by the companion star or does not exist at all. You would need more observations with a different technique to figure that out.

As part of their study, Lester and her colleagues also analyzed how far apart the stars are in the binary systems where TESS had detected large planets. The team found that the stars in the exoplanet-hosting pairs were typically farther apart than binary stars not known to have planets.[6] This could suggest that planets do not form around stars that have close stellar companions.

This speckle imaging survey illustrates the critical need for NSF telescope facilities to characterize newly discovered planetary systems and develop our understanding of planetary populations, said National Science Foundation Division of Astronomical Sciences Program Officer Martin Still.

This is a major finding in exoplanet work, Howell commented. The results will help theorists create their models for how planets form and evolve in double-star systems.

Notes

This research is presented in the paper Speckle Observations of TESS Exoplanet Host Stars. II. Stellar Companions at 1-1000 AU and Implications for Small Planet Detection to appear in the Astronomical Journal.

Reference: Speckle Observations of TESS Exoplanet Host Stars. II. Stellar Companions at 1-1000 AU and Implications for Small Planet Detection by Kathryn V. Lester, Rachel A. Matson, Steve B. Howell, Elise Furlan, Crystal L. Gnilka, Nicholas J. Scott, David R. Ciardi, Mark E. Everett, Zachary D. Hartman and Lea A. Hirsch, Accepted, Astronomical Journal.arXiv:2106.13354

The team is composed of Kathryn V. Lester (NASA Ames Research Center), Rachel A. Matson (US Naval Observatory), Steve B. Howell (NASA Ames Research Center), Elise Furlan (Exoplanet Science Institute, Caltech), Crystal L. Gnilka (NASA Ames Research Center), Nicholas J. Scott (NASA Ames Research Center), David R. Ciardi (Exoplanet Science Institute, Caltech), Mark E. Everett (NSFs NOIRLab), Zachary D. Hartman (Lowell Observatory & Department of Physics & Astronomy, Georgia State University), and Lea A. Hirsch (Kavli Institute for Particle Astrophysics and Cosmology, Stanford University).

NSFs NOIRLab (National Optical-Infrared Astronomy Research Laboratory), the US center for ground-based optical-infrared astronomy, operates the international Gemini Observatory (a facility of NSF, NRCCanada, ANIDChile, MCTICBrazil, MINCyTArgentina, and KASIRepublic of Korea), Kitt Peak National Observatory (KPNO), Cerro Tololo Inter-American Observatory (CTIO), the Community Science and Data Center (CSDC), and Vera C. Rubin Observatory (operated in cooperation with the Department of Energys SLAC National Accelerator Laboratory). It is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with NSF and is headquartered in Tucson, Arizona. The astronomical community is honored to have the opportunity to conduct astronomical research on Iolkam Duag (Kitt Peak) in Arizona, on Maunakea in Hawaii, and on Cerro Tololo and Cerro Pachn in Chile. We recognize and acknowledge the very significant cultural role and reverence that these sites have to the Tohono Oodham Nation, to the Native Hawaiian community, and to the local communities in Chile, respectively.

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Are We Missing Other Earths? Dramatic New Evidence Uncovered by Astronomers - SciTechDaily

When did the first stars start shining? Researchers are now closer than ever to the answer. Work led by scientists in the UK places cosmic dawn between 250 and 350 million years after the Big Bang.The researchers alsobelieve the first galaxies hosting these first stars might soon become observable to our instruments.

The research, published in the Monthly Notices of the Royal Astronomical Society, set out to expand our understanding of one of the most mysterious times of our universe: the cosmic dark ages. For hundreds of millions of years, no (visible) light shone in the cosmos. Slowly but surely, gas began to clump up in large clouds and from these clouds, due to gravitational collapse, the first stars were born.

The team estimated this by looking at six of the furthest galaxies ever discovered. Looking far into the universe is like looking into the past, due to the finiteness of the speed of light. The light of these half-a-dozen objects comes to us from when the Universe was just 550 million years old. They then estimated the age of these galaxies, suggesting when the stars in them were born.

Witnessing the moment when the universe was first bathed in starlight is a major quest in astronomy, lead author Dr Nicolas Laporte, from the University of Cambridge, said in a statement.

Our observations indicate that cosmic dawn occurred between 250 and 350 million years after the beginning of the universe, and, at the time of their formation, galaxies such as the ones we studied would have been sufficiently luminous to be seen with the James Webb Space Telescope.

Thanks to observations from the Hubble and Spitzer space telescopes, the team was able to estimate the presence of atomic hydrogen. During the cosmic dark ages, all hydrogen was atomic hydrogen, but the light of stars ripped the electrons from those hydrogen atoms (a process called ionization). By the end of cosmic dawn, the vast majority of hydrogen in the universe was once again ionized.

This fact is important by estimating how much hydrogen is left to be ionized in a galaxy, you can work out how long its stars have been active. It is a good way to date the formation of these objects and their stars.

This age indicator is used to date stars in our own neighbourhood in the Milky Way but it can also be used to date extremely remote galaxies, seen at a very early period of the universe, added co-author Dr Romain Meyer, from University College London and the Max Planck Institute for Astronomy in Heidelberg, Germany.

Using this indicator we can infer that, even at these early times, our galaxies are between 200 and 300 million years old.

The light of the first galaxies might soon be in our grasp (and telescopes).

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Astronomers Are Zeroing In On The Birth Of The First Stars - IFLScience

Astronomers spy rocky and icy wanderers of all shapes and sizes zipping past Earth all the time. But earlier this month, they were flabbergasted when they caught sight of the largest comet theyd ever seen.

One of its discoverers, Pedro Bernardinelli, an astrophysicist at the University of Pennsylvania, conservatively estimates the objects dusty, icy nucleus is between 62 and 125 miles long. That means this comet is as small as five Manhattan Islands, or its larger than the Island of Hawaii. Hale-Bopp, which lit up night skies in the late 1990s with its 25-mile-long nucleus, was long perceived to be a giant among comets. But the nucleus of this comet, Comet C/2014 UN271, is still two or three Hale-Bopps across, said Teddy Kareta, a planetary astronomy graduate student at the University of Arizona. Its just wild.

With a reasonable degree of certainty, its the biggest comet that weve ever seen, said Colin Snodgrass, an astronomer at the University of Edinburgh.

The comet is currently inside Neptunes orbit. Over the next decade, it will scoot toward the inner solar system. More of its ices will be vaporized by the suns glare, causing it to effervesce and brighten. In 2031, it will get within a billion miles of the sun almost but not quite making it to Saturn before journeying back to the coldest, darkest fringes of our galactic neighborhood.

Although its unlikely a spacecraft will be able to rendezvous with the comet, spotting it while its still two billion miles away means that astronomers can train their telescopes on it and watch it flare, then fade, in staggering detail over the next 20 years.

Comets are like cats. You never know what theyre going to do, said Meg Schwamb, an astronomer at Queens University Belfast. Im ready to get the popcorn.

Comets are icy remnants as old as the sun, and may have delivered both water and organic matter to the solar systems rocky worlds. This frosty leviathan, then, is a fantastic opportunity to uncover a bounty of cometary secrets.

It was first spotted with the Dark Energy Survey, an effort to map distant galaxies and exploding stars in order to investigate the universes accelerating expansion. To galaxy hunters, all those rocks in the foreground are just a nuisance, Dr. Snodgrass said. But to comet chasers, theyre quite an interesting nuisance.

A search of the surveys databanks found over 800 novel iceballs with orbits larger than Neptunes. One, designated 2014 UN271, was by far the most interesting one we found, Dr. Bernardinelli said.

A series of images of the icy object captured from 2014 to 2018 revealed it was definitely icy, probably elongated, and had emerged from the Oort cloud, an expansive shell of primordial space debris surrounding the solar system nothing unusual so far. But when its dramatic dimensions were announced on June 19, scientists were blown away. Its not even close to being the largest object beyond Neptune. But its sunward trajectory meant that, if its ices transmogrified into gases, it would become the largest comet ever found.

Their curiosities piqued, Dr. Snodgrass, Dr. Schwamb and their colleagues used telescopes in South Africa and Namibia to take a closer look and they spied a coma, an envelope of gas, surrounding it. Despite its considerable distance, some of its more volatile ices carbon dioxide and carbon monoxide, perhaps were already being vaporized by slivers of sunlight.

It was official: This was a colossal comet. On June 24, this newly identified gadabout was renamed Comet C/2014 UN271 (Bernardinelli-Bernstein) after its discoverers Dr. Bernardinelli and Gary Bernstein, an astronomer at the University of Pennsylvania.

This comet takes roughly three million years to make one complete circumnavigation of the sun. The last time it was here, modern humans had yet to evolve. The next time it comes around, who can say what will have come of our species. This may be the only chance humanity will get to glimpse it.

In 2031, if you take a halfway-decent telescope to a dimly lit area, you will be able to see this specter shift among the stars. At a distance of one billion miles, it wont provide the cinematic streak some comets are famous for, but you will see a flicker of light.

Many of the night skys flickers belong to unfathomably distant objects. But not comets and, like all its icy cousins, this one is both weird and beautiful, Mr. Kareta said. Its visitation reminds us that the universe isnt a static expanse, but a chaotic ballet, full of wondrous things always in motion.

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The Largest Comet Ever Found Is Making Its Move Into a Sky Near You - The New York Times

Institute for Astronomy

Naming asteroids is serious business. In the latest batch of officially named asteroids, five have been given names honoring astronomers at the University of Hawaii Institute for Astronomy (IfA).

The International Astronomical Union Committee for Small Body Nomenclature is responsible for designating and naming minor planets. If an object has been observed for at least two nights and is proven to be a newly-identified object, it is assigned an initial provisional designation. If enough observations are obtained to calculate an orbit, the object is assigned a sequential numerical designation. The asteroids discoverer can then propose a formal name.

Newly designated asteroids

These five new designations join a cornucopia of at least 40 asteroids named after current and former IfA astronomers, students, staff and other individuals.

For a full list, please go to the IfA website.

More here:

Asteroids named after UH astronomers | University of Hawaii System News - UH System Current News

Aryan Mishra, 21, son of a newspaper seller, made headlines when he discovered an asteroid at the age of 14.

He was set to build astronomy labs in government schools in 2019 after being approached by the Central government. The idea hasnt taken off yet and he and his colleagues Shishirant Rahul, Shakeel Ahmad, and Naveen Sharma have been able to set up only 15 labs across the country, including in only three government schools in Jammu, Leh and Kargil.

The governments idea was to set up 500 astronomy labs across the country. I dont know why the idea hasnt taken off yet. Delhi government schools have done well over the last few years. I hope we can take the idea forward. Unfortunately, I havent been able to meet Delhi Deputy Chief Minster Manish Sisodia. I have tried many times though, Mr. Mishra, now a third-year BSc student of a private university said. He is studying on scholarship.

The idea of astronomy lab a start-up called Spark Astronomy was conceived in 2018 when Mr. Mishra had just graduated from Class 12 and had got into several universities in the U.S. but had to cancel his plans because he couldnt arrange the funds.

Honestly, I thought that with this start-up, Ill also be able to fund my education but unfortunately, that didnt happen. And the whole idea behind it was to make science accessible and easy for those who are interested, he said.

The lab which roughly costs 4.5 lakh and 20 days to fully set up has telescopes, planispheres, moon mapping catalogue among other articles.

Now, this group of four is working towards making low-cost telescopes so those who want to see the sky can see it freely. The feeling was invoked because of Mr. Mishras personal experience as a child and the hardships he had to face coming from a humble background.

He was born to Birbal Mishra and Shashi Mishra, both uneducated who had come to the city from their hometown in Uttar Pradesh, 32 years ago, in search of a better life. Mr. Mishra recalled how his father used to sell vegetables in the initial years when he came here and then worked as a watchman for 10 years while selling newspapers with his brother. Though he has quit the watchman job, he continues to deliver newspapers in Vasant Vihar and Shanti Niketan.

Mr. Mishra got into a charity school where his parents managed to pay the fees because they wanted their children Aryan and his sister to study because they couldnt.

While living in the slums at Kusumpur Pahadi, I got a clear view of the sky. There were no big buildings that blocked my view and I was a curious child who had so many questions about what goes on up there. I used to ask my teachers at school and finally joined the astronomy club, he said, adding that a cyber cafe in the vicinity helped him a lot.

I used to spend a lot of time there and thats also where I discovered the asteroid from. He never used to charge extra money from me for sitting there for extra hours.

Mr. Mishra managed to buy a telescope, while in school, by saving up money.

After the asteroid discovery, he got appreciation from different corners and was invited for talks but all the fame never really translated into anything tangible, he added.

I never received any monetary or other help from anyone to enable me to do anything. I have done everything on my own and with my familys help. I continue to stay in the slums. Only now I live in a pucca house and also have a personal phone, he said.

Some incidents of the past still hurt though, Mr. Mishra said recalling an episode from school time when he was helping his father with delivering newspapers. A few students travelling in the school bus had seen him and informed school authorities. They called my parents and told them that they shouldnt because I am a child. But sympathy wouldnt have fed my family.

Excerpt from:

500 astronomy labs yet to see light of day - The Hindu

Artists concept of a cosmic filament a strand in the cosmic web, containing galaxies and dark matter stretching from one galaxy cluster to another. Fantastically, astronomers now say these vast filaments spin in space. Image via AIP/ A. Khalatyan/ J. Fohlmeister.Filaments of the cosmic web

Astronomers at the Leibniz Institute for Astrophysics Potsdam, in collaboration with scientists in China and Estonia, said on June 14, 2021, that theyve discovered a rotation a spin on an enormous scale never seen before. They made the discovery by mapping the motion of galaxies in huge filaments or strands of whats called the cosmic web. They were looking at the universe on the grandest scale, in which there are great filaments made of galaxies, separated by giant voids. And they found that these long tendrils of galaxies and matter, forming the vast cosmic filaments of the cosmic web, rotate on the scale of hundreds of millions of light-years.

Its the largest rotation in the universe, these astronomers said.

You know how ice skaters spin faster as they pull in their arms? Scientists describe that faster spin as due to conservation of angular momentum. These astronomers said their results:

signify that angular momentum can be generated on unprecedented scales.

The study was published on June 14, 2021, in the peer-reviewed journal Nature Astronomy.

So the cosmic filaments are essentially galaxy-packed bridges. And you might ask, from where to where? Astronomers say that vast clusters of galaxies lie at the nodes, or connection points, of the cosmic web. A cosmic filament made of galaxies now known to be spinning spans the vast distant between clusters of galaxies.

Noam Libeskind at the Leibniz Institute for Astrophysics Potsdam, initiator of the project, said that galaxies:

move on helixes or corkscrew like orbits, circling around the middle of the filament while travelling along it. Such a spin has never been seen before on such enormous scales, and the implication is that there must be an as yet unknown physical mechanism responsible for torquing these objects.

He also described the filaments themselves as thin cylinders:

similar in dimension to pencils, hundreds of millions of light-years long, but just a few million light-years in diameter.

And he added:

These fantastic tendrils of matter rotate. On these scales, the galaxies within them are themselves just specks of dust.

As Noam Libeskind said above, the galaxies in the filaments funnel on corkscrew paths into the clusters at their ends. Thus, to us on Earth, the light of the funneling galaxies appears red-shifted when moving away from us, and blue-shifted when moving toward us. Astronomers can measure a shift like that.

These astronomers measured red and blue shifts using existing data in the Sloan Digital Sky Survey, which began collecting data in 2000. Peng Wang of the Leibniz Institute for Astrophysics Potsdam explained:

By mapping the motion of galaxies in these huge cosmic superhighways using the Sloan Digital Sky survey a survey of hundreds of thousands of galaxies we found a remarkable property of these filaments: they spin.

In hindsight, its logical to think that the filaments would spin. After all, there must have been a period during which as the early universe expanded outward from the Big Bang, and as galaxies began to form the galaxies for some reason pulled themselves into these vast filaments, creating the cosmic web in the first place. And, as they did so, its easy to think of the filaments spinning up, like ice skaters pulling in their arms.

In fact, it was earlier work by theorist Mark Neyrinck that caused these astronomers to analyze the Sloan Digital Sky Survey data. Libeskind said:

Its fantastic to see this confirmation that intergalactic filaments rotate in the real universe, as well as in computer simulation.

The scientists still wonder, though, why do they spin? Or perhaps its better to ask the question as how. How is the angular momentum generated? What made the galaxies pull themselves together into filaments? Why does the universe appear as a cosmic web at all?

Bottom line: Astronomers have found the largest rotation in the universe by analyzing red and blue shifts in galaxies. The galaxies compose strands or filaments in the cosmic web. Those filaments are now believed to be spinning.

Source: Possible observational evidence for cosmic filament spin

Via Leibniz Institute for Astrophysics Potsdam

Kelly Kizer Whitt has been a science writer specializing in astronomy for more than two decades. She began her career at Astronomy Magazine, and she has made regular contributions to AstronomyToday and the Sierra Club, among other outlets. Her childrens picture book, Solar System Forecast, was published in 2012. She has also written a young adult dystopian novel titled A Different Sky. When she is not reading or writing about astronomy and staring up at the stars, she enjoys traveling to the national parks, creating crossword puzzles, running, tennis, and paddleboarding. Kelly lives with her family in Wisconsin.

Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.

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Astronomers spot largest rotation in the universe - EarthSky

This article was originally published atThe Conversation.The publication contributed the article to Space.com'sExpert Voices: Op-Ed & Insights.

Lisa Kewley, Director, ARC Centre for Excellence in All-Sky Astrophysics in 3D, Australian National University

It will take until at least 2080 before women make up just one-third of Australia's professional astronomers unless there is a significant boost to how we nurture female researchers' careers.

Over the past decade, astronomy has been rightly recognized as leading the push towards gender equity in the sciences. But my new modeling,published in Nature Astronomy, shows it is not working fast enough.

Related: 20 trailblazing women in astronomy and astrophysics

TheAustralian Academy of Science's decadal planfor astronomy in Australia proposes women should comprise one-third of the senior workforce by 2025.

It's a worthy, if modest, target. However, with new data from the academy's Science in Australia Gender Equity (SAGE) program, I have modeled the effects of current hiring rates and practices and arrived at a depressing, if perhaps not surprising, conclusion. Without a change to the current mechanisms, it will take at least 60 years to reach that 30% level.

However, the modeling also suggests that the introduction of ambitious, affirmative hiring programs aimed at recruiting and retaining talented women astronomers could see the target reached in just over a decade and then growing to 50% in a quarter of a century.

Before looking at how that might be done, it's worth examining how the gender imbalance in physics arose in the first place. To put it bluntly: how did we get to a situation in which 40% of astronomy PhDs are awarded to women, yet they occupyfewer than 20% of senior positions?

On a broad level, the answer is simple: my analysis shows women depart astronomy at two to three times the rate of men. In Australia, from postdoc status to assistant professor level, 62% of women leave the field, compared with just 17% of men. Between assistant professor and full professor level, 47% of women leave; the male departure rate is about half that. Women's departure rates aresimilar in US astronomy.

Read more:'Death by a thousand cuts': women of color in science face a subtly hostile work environment

The next question is: why?

Many women leave out of sheer disillusionment. Women in physics and astronomy say their careers progress more slowly than those of male colleagues, and that the culture is not welcoming.

They receive fewer career resources and opportunities. Randomized double-blind trials and broad research studies in astronomy and across the sciences show implicit bias in astronomy, which means more men arepublished,cited,invited to speak at conferences, and giventelescopetime.

It's hard to build a solid research-based body of work when one's access to tools and recognition is disproportionately limited.

There is another factor that sometimes contributes to the loss of women astronomers: loyalty. In situations where a woman's male partner is offered a new job in another town or city, the woman more frequentlygives up her work to facilitate the move.

Encouraging universities or research institutes to help partners find suitable work nearby is thus one of the strategies I (and others) have suggested to help recruit women astrophysicists.

But the bigger task at hand requires institutions to identify, tackle and overcome inherent bias a legacy of a conservative academic tradition that,research shows, is weighted towards men.

A key mechanism to achieve this was introduced in 2014 by the Astronomical Society of Australia. It devised a voluntary rating and assessment system known as thePleiades Awards, which rewards institutions for taking concrete actions to advance the careers of women and close the gender gap.

Initiatives include longer-term postdoctoral positions with part-time options, support for returning to astronomy research after career breaks, increasing the fraction of permanent positions relative to fixed-term contracts, offering women-only permanent positions, recruitment of women directly to professorial levels, and mentoring of women for promotion to the highest levels.

Most if not all Australian organizations that employ astronomers have signed up to the Pleiades Awards, and are showing genuine commitment to change.

Seven years on, we would expect to have seen an increase in women recruited to, and retained in, senior positions.

And we are, but the effect is far from uniform. My own organization, the ARC Centre of Excellence in All-Sky Astrophysics in 3 Dimensions (ASTRO 3D), is on track for a 50:50 women-to-men ratio working at senior levels by the end of this year.

TheUniversity of Sydney School of Physicshas made nine senior appointments over the past three years, seven of them women.

But these examples are outliers. At many institutions, inequitable hiring ratios and high departure rates persist despite a large pool of women astronomers at postdoc levels and the positive encouragement of the Pleiades Awards.

Using these results and my new workforce models, I have shown current targets of 33% or 50% of women at all levels are unattainable if the status quo remains.

I propose a raft of affirmative measures to increase the presence of women at all senior levels in Australian astronomy and keep them there.

These include creating multiple women-only roles, creating prestigious senior positions for women, and hiring into multiple positions for men and women to avoid perceptions of tokenism. Improved workplace flexibility is crucial to allowing female researchers to develop their careers while balancing other responsibilities.

Read more:Isaac Newton invented calculus in self-isolation during the Great Plague. He didn't have kids to look after

Australia is far from unique when it comes to dealing with gender disparities in astronomy. Broadly similar situations persist in China, the United States and Europe. AnApril 2019 paperoutlined similar discrimination experienced by women astronomers in Europe.

Australia, however, is well placed to play a leading role in correcting the imbalance. With the right action, it wouldn't take long to make our approach to gender equity as world-leading as our research.

This article is republished fromThe Conversationunder a Creative Commons license. Read theoriginal article.

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Looking at the stars, or falling by the wayside? How astronomy is failing female scientists - Space.com