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The central parts of our Galaxy, the Milky Way, as observed in the near-infrared with the NACO instrument on ESO’s Very Large Telescope. By following the motions of the most central stars over more than 16 years, astronomers were able to determine the mass of the supermassive black hole that lurks there. Credit: ESO/S. Gillessen et al.

Reinhard Genzel and Andrea Ghez have jointly been awarded the 2020 Nobel Prize in Physics for their work on the supermassive black hole, Sagittarius A*, at the center of our galaxy. Genzel, Director at the Max Planck Institute for Extraterrestrial Physics in Germany, and his team have conducted observations of Sagittarius A* for nearly 30 years using a fleet of instruments on European Southern Observatory (ESO) telescopes.

Genzel shares half of the prize with Ghez, a professor at the University of California, Los Angeles in the US, “for the discovery of a supermassive compact object at the center of our galaxy”, with the other half awarded to Roger Penrose, professor at the University of Oxford in the UK, “for the discovery that black hole formation is a robust prediction of the general theory of relativity.” 

“Congratulations to all three Nobel laureates! We are delighted that the research on the supermassive black hole at the center of our galaxy has been recognized with the 2020 Nobel Prize in Physics. We are proud that the telescopes ESO builds and operates at its observatories in Chile played a key role in this discovery,” says ESO’s Director General Xavier Barcons. “The work done by Reinhard Genzel with ESO telescopes and by Andrea Ghez with the Keck telescopes in Hawaii has enabled unprecedented insight into Sagittarius A*, which confirmed predictions of Einstein’s general relativity.”

ESO has worked in very close collaboration with Genzel and his group for around 30 years. Since the early 1990s, Genzel and his team, in cooperation with ESO, have developed instruments designed to track the orbits of stars in the Sagittarius A* region at the center of the Milky Way. 

They started their campaign in 1992 using the SHARP instrument on ESO’s New Technology Telescope (NTT) at the La Silla Observatory in Chile. The team later used extremely sensitive instruments on ESO’s Very Large Telescope (VLT) and the Very Large Telescope Interferometer at the Paranal Observatory, namely NACO, SINFONI and later GRAVITY, to continue their study of Sagittarius A. 

In 2008, after 16 years of tracking stars orbiting Sagittarius A*, the team delivered the best empirical evidence that a supermassive black hole exists at the center of our galaxy. Both Genzel’s and Ghez’s groups accurately traced the orbit of one star in particular, S2, which reached the closest distance to Sagittarius A* in May 2018. ESO undertook a number of developments and infrastructure upgrades in Paranal to enable accurate measurements of the position and velocity of S2.

The team led by Genzel found the light emitted by the star close to the supermassive black hole was stretched to longer wavelengths, an effect known as gravitational redshift, confirming for the first time Einstein’s general relativity near a supermassive black hole. Earlier this year, the team announced they had seen S2 ‘dance’ around the supermassive black hole, showing its orbit is shaped like a rosette, an effect called Schwarzschild precession that was predicted by Einstein.

Genzel and his team are also involved in the development of instruments that will be installed on ESO’s Extremely Large Telescope, currently under construction in Chile’s Atacama Desert, which will enable them to probe the environment even closer to the supermassive black hole.

Earth’s Moon and Planet Mars will be just over one degree apart at 12:18 AM EDT, Saturday, October 3, as viewed from the Hiram, Ohio area. Credit: Sky Safari/James Guilford

The night of October 2 – 3 will see a brilliant pairing of lights, a conjunction, in our night sky. Earth’s Moon and planet Mars will shine close together — only a smidgen over a degree apart — in the southeast. As viewed from the Hiram, Ohio area, Moon and Mars will be nearest each other at 12:18 AM EDT. Don’t worry if you can’t stay up, the two will be a beautiful pair to behold all night long.

Our Moon will be a day past Full and in its Waning Gibbous phase, so it will be round and bright. Mars, while too distant to be seen as a disc by the unaided eye, is nearing an unusually close approach to Earth during its opposition and will shine like a coppery star. Mars will be nearest to Earth, at 62 million kilometers (38,525,014 miles) distant, on October 6 and it won’t be that close again until 2035.

Opposition refers to a time in their orbits when Mars (or another planet) is opposite the Earth from the Sun — around that time is when the two bodies, on concentric racetrack orbits around the Sun, pass each other and are at their closest and brightest.

At 6:24 AM EDT, September 30, a surprising light appeared in the predawn sky over Hiram — an extremely bright fireball meteor flared overhead! A fireball meteor is a meteor that appears brighter than the planet Venus. Reports of the flare were made by startled observers over eastern Ohio and western Pennsylvania.

Hiram College is home to a NASA All-Sky Fireball Network camera system that watches for bright meteors every clear night. Recorded events are uploaded to NASA for analysis which aids in assessing threats to spacecraft by high-velocity solar system debris.

Cleveland, Ohio’s WKYC television published a report on the event along with several other video clips. Click Here to see their story.

Hiram College has been home to the NASA all-sky camera since 2013. The camera sits atop one of the buildings on the college campus and is maintained in cooperation with NASA’s Meteoroid Environment Office.

This artistic illustration depicts the Venusian surface and atmosphere. Credit: ESO/M. Kornmesser

An international team of astronomers today announced the discovery of a rare molecule — phosphine — in the clouds of Venus. On Earth, this gas is only made industrially or by microbes that thrive in oxygen-free environments. Astronomers have speculated for decades that high clouds on Venus could offer a home for microbes — floating free of the scorching surface but needing to tolerate very high acidity. The detection of phosphine could point to such extra-terrestrial “aerial” life. Confirming the presence of life, however, will require much more work.

“When we got the first hints of phosphine in Venus’s spectrum, it was a shock!”, says team leader Jane Greaves of Cardiff University in the UK, who first spotted signs of phosphine in observations from the James Clerk Maxwell Telescope (JCMT), operated by the East Asian Observatory, in Hawaiʻi. Confirming their discovery required using 45 antennas of the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, a more sensitive telescope in which the European Southern Observatory (ESO) is a partner. Both facilities observed Venus at a wavelength of about 1 millimeter, much longer than the human eye can see — only telescopes at high altitude can detect it effectively.

The international team, which includes researchers from the UK, US and Japan, estimates that phosphine exists in Venus’s clouds at a small concentration, only about twenty molecules in every billion. Following their observations, they ran calculations to see whether these amounts could come from natural non-biological processes on the planet. Some ideas included sunlight, minerals blown upwards from the surface, volcanoes, or lightning, but none of these could make anywhere near enough of it. These non-biological sources were found to make at most one ten thousandth of the amount of phosphine that the telescopes saw.

To create the observed quantity of phosphine (which consists of hydrogen and phosphorus) on Venus, terrestrial organisms would only need to work at about 10% of their maximum productivity, according to the team. Earth bacteria are known to make phosphine: they take up phosphate from minerals or biological material, add hydrogen, and ultimately expel phosphine. Any organisms on Venus will probably be very different to their Earth cousins, but they too could be the source of phosphine in the atmosphere.

While the discovery of phosphine in Venus’s clouds came as a surprise, the researchers are confident in their detection. “To our great relief, the conditions were good at ALMA for follow-up observations while Venus was at a suitable angle to Earth. Processing the data was tricky, though, as ALMA isn’t usually looking for very subtle effects in very bright objects like Venus,” says team member Anita Richards of the UK ALMA Regional Centre and the University of Manchester. “In the end, we found that both observatories had seen the same thing — faint absorption at the right wavelength to be phosphine gas, where the molecules are backlit by the warmer clouds below,” adds Greaves, who led the study published today in Nature Astronomy.

Another team member, Clara Sousa Silva of the Massachusetts Institute of Technology in the US, has investigated phosphine as a “biosignature” gas of non-oxygen-using life on planets around other stars, because normal chemistry makes so little of it. She comments: “Finding phosphine on Venus was an unexpected bonus! The discovery raises many questions, such as how any organisms could survive. On Earth, some microbes can cope with up to about 5% of acid in their environment — but the clouds of Venus are almost entirely made of acid.”

The team believes their discovery is significant because they can rule out many alternative ways to make phosphine, but they acknowledge that confirming the presence of “life” needs a lot more work. Although the high clouds of Venus have temperatures up to a pleasant 30 degrees Celsius, they are incredibly acidic — around 90% sulfuric acid — posing major issues for any microbes trying to survive there.

ESO astronomer and ALMA European Operations Manager Leonardo Testi, who did not participate in the new study, says: “The non-biological production of phosphine on Venus is excluded by our current understanding of phosphine chemistry in rocky planets’ atmospheres. Confirming the existence of life on Venus’s atmosphere would be a major breakthrough for astrobiology; thus, it is essential to follow-up on this exciting result with theoretical and observational studies to exclude the possibility that phosphine on rocky planets may also have a chemical origin different than on Earth.”

More observations of Venus and of rocky planets outside our Solar System, including with ESO’s forthcoming Extremely Large Telescope, may help gather clues on how phosphine can originate on them and contribute to the search for signs of life beyond Earth.

Fireball image captured at 11:36 PM EDT, August 11, 2020 by Hiram’s NASA All-Sky Fireball Network camera. The time stamp in the camera image reads 03:36 UTC — Coordinated Universal Time — which converts to 11:36 PM EDT. Credit: NASA

 

by James Guilford

Hey! That’s my fireball!!

I had stepped outdoors to check the sky (hoping to see at least one Perseid Meteor) and witnessed a fireball  at 11:36 PM; it was captured by the NASA All-Sky Fireball Network camera system hosted by Hiram College. That was the first time I had spotted a meteor that was also captured by the automated camera. The “shooting star” is not very impressive in the picture but it was a beauty by eye, glowing brightly and leaving a long “smoke trail” as it traveled from south to north.

Below is a summary of the data the NASA system was able to derive from Hiram, Oberlin College, and Allegheny Observatory imagery. Rather than a Perseids meteor, it was classified as an Alpha Capricornids meteor — that shower peaked in late July.

Data Summary for the fireball recorded at 11:36 PM EDT, August 11, 2020. Credit: NASA

 

If you are interested in NASA’s All-Sky Fireball Network, here’s a link to their website. Meteor data are updated daily with image captures and event summaries. Hiram’s is one of 17 all-sky cameras located in the continental U.S. https://fireballs.ndc.nasa.gov.

On August 13, 2013, Hiram College became the host for one of NASA’s All-Sky Camera Fireball Network stations, Oberlin College and Allegheny Observatory joining with us. The automated camera system watches the sky every night for exceptionally-bright meteors called fireballs.

James Guilford operates Stephens Memorial Observatory for the Physics Department of Hiram College.

 

A fireball meteor streaks across the sky north of Hiram at 3:38 AM, August 8, 2020. The large white “blob” in this image is the waning Gibbous Moon. Credit: NASA All-Sky Fireball Network/Hiram College Camera

It’s Perseids season!

The annual Perseid Meteor Shower peaks from August 11 to 13, the event many consider to be the best meteor shower of the year, thanks to frequent meteors streaking across the sky and comfortable nighttime temperatures. This year, skywatchers can expect to see between 50 and 75 meteors an hour under dark skies, or about one meteor every minute. The meteors are bits of material strewn across Earth’s path in space by Comet 109P/Swift-Tuttle. The bits of dust and grit glow brightly as they burn up while entering Earth’s atmosphere at about 37 miles per second.

This year, for those who venture out before midnight on the peak date(s), Earth’s Moon won’t interfere. Dedicated meteor spotters — those who observe in the wee hours between midnight and dawn — may curse as Moon rises and brightens the sky, making faint meteors harder to see. There is another problem, however, much closer to home: the weather.

 

2020 Perseids Viewing Forecast for the continental United States. Credit: Accuweather

 

The weather forecast calls for mostly cloudy skies Tuesday and Wednesday nights. Of course.

Do not abandon hope.

The nights preceding and following the shower’s peak see occasional meteors from the Perseid and Alpha Capricornid showers and include fireballs (very bright meteors) from both. When the sky’s clear, go out and enjoy the mild nights that may include “shooting stars.” After twilight fades, find a dark spot, spread out a blanket, or untangle that deck lounge chair, apply a little mosquito repellent and look up. As your eyes grow used to the dark you’ll see more and more stars, planets Jupiter and Saturn gracing the southern sky, and with decently dark sky, spy the soft clouds of our own Milky Way galaxy. You’ll probably see a satellite or two, too.

 

Our Night Sky: August 11, 2020, 11:59 PM. Note: The bright dot that appears to be labeled Pluto is actually Jupiter! Pluto is the tiny purple speck next to it and you won’t be able to see Pluto. Credit: SkySafari — CLICK FOR FULL-SIZE IMAGE

 

A stellar butterfly

StephensAstro —  July 30, 2020 — 1 Comment

This highly detailed image of the fantastic NGC 2899 planetary nebula was captured using the FORS instrument on ESO’s Very Large Telescope in northern Chile. This object has never before been imaged in such striking detail, with even the faint outer edges of the planetary nebula glowing over the background stars. Credit: ESO

Resembling a butterfly with its symmetrical structure, beautiful colors, and intricate patterns, this striking bubble of gas — known as NGC 2899 — appears to float and flutter across the sky in this new picture from the European Southern Observatory’s Very Large Telescope (VLT). This object has never before been imaged in such striking detail, with even the faint outer edges of the planetary nebula glowing over the background stars.

NGC 2899’s vast swathes of gas extend up to a maximum of two light-years from its center, glowing brightly in front of the stars of the Milky Way as the gas reaches temperatures upwards of ten thousand degrees. The high temperatures are due to the large amount of radiation from the nebula’s parent star, which causes the hydrogen gas in the nebula to glow in a reddish halo around the oxygen gas, in blue.

This object, located between 3000 and 6500 light-years away in the Southern constellation of Vela (The Sails), has two central stars, which are believed to give it its nearly symmetric appearance. After one star reached the end of its life and cast off its outer layers, the other star now interferes with the flow of gas, forming the two-lobed shape seen here. Only about 10–20% of planetary nebulae [1] display this type of bipolar shape.

Astronomers were able to capture this highly detailed image of NGC 2899 using the FORS instrument installed on UT1 (Antu), one of the four 8.2-meter telescopes that make up ESO’s VLT in Chile. Standing for FOcal Reducer and low dispersion Spectrograph, this high-resolution instrument was one of the first to be installed on ESO’s VLT and is behind numerous beautiful images and discoveries from ESO. FORS has contributed to observations of light from a gravitational wave source, has researched the first known interstellar asteroid, and has been used to study in depth the physics behind the formation of complex planetary nebulae.

This image was created under the ESO Cosmic Gems program, an outreach initiative to produce images of interesting, intriguing or visually attractive objects using ESO telescopes, for the purposes of education and public outreach. The program makes use of telescope time that cannot be used for science observations. All data collected may also be suitable for scientific purposes, and are made available to astronomers through ESO’s science archive.

Purity and Pollution. Comet C/2020 F3 NEOWISE floats serenely among stars above clouds glowing brightly from light pollution. Photo by James Guilford.

Comet C/2020 F3 (NEOWISE) was, for us in North America, a predawn object requiring exceptional dedication for observing.  In the second week of July, the comet had moved enough in its orbit to become visible in the evening sky — from late twilight to about 11 p.m. Unfortunately, cloudy nights have been the rule lately so opportunities have been few.

On Wednesday night, July 15, the sky forecast was a bit shaky but it turned out the sky cleared enough to allow C/2020 F3 to be seen. I raced off to an observing site some 25 minutes away from home, popular with sunset watchers and, occasionally, comet spotters. Arriving at the site I found the place mobbed, the parking lot nearly full, by scores of would-be comet viewers. Unfortunately, the comet was pretty much at the low end of naked-eye visibility. Light pollution reduced contrast between comet and background sky to make the object nearly invisible — binoculars were needed. It’s likely most of those in attendance never saw the comet.

Entitled “Purity and Pollution,” this picture (a single exposure of 8 seconds) shows a pristine wonder of the night sky floating serenely amongst the stars, clouds glowing brightly below illuminated by artificial light pollution. If we were only more careful with our artificial light, we’d save plentiful energy (and money) and gain back our starry skies as a bonus!

C/2020 F3 (NEOWISE) will be gracing our night skies for the next week or so and I hope to have more than one opportunity to record the event before it is gone. The next apparition of this comet is expected in about 6,800 years.

Seen at 5:00 in the morning, July 9, 2020, C/2020 F3 rises over calm Lake Erie waters and predawn colors. Photo by James Guilford.

The talk amongst stargazers this summer has been the apparition of C/2020 F3 NEOWISE in Northern Hemisphere skies. Previously one comet had caused excitement over its potential showing but it broke up as it approached the Sun. Another fizzled and faded from view. But C/2020 F3 survived its July 3 close approach to the sun (perihelion) and emerged bigger and brighter than expected.

The comet’s brightness is due to its large nucleus — the head of the comet — which is the source of frozen gas and dust that produces the visible tail or coma. “From its infrared signature, we can tell that [the nucleus] is about 5 kilometers across,” said Joseph Masiero, NEOWISE deputy principal investigator at NASA’s Jet Propulsion Laboratory.

C/2020 F3 was discovered in infrared images captured by NASA’s NEOWISE spacecraft in March 2020. The object was assigned the unromantic designation of C/2020 F3 with the spacecraft’s name as discoverer.

Comet C/2020 F3 with normal exposure (top), then brightened in processing to bring out fuller extent of its dust trail (lower image). Photo by James Guilford.

Falling in from the outer solar system, then diving perilously close to the Sun gave our comet a boost in speed and increased its orbital period from about 4,500 years to about 6,800 years — a long time to wait for its return.

Until recently C/2020 F3 put in its appearances only in the predawn hours, rising a little after 3:30 AM and fading into the brightening sky a bit past 5:00 AM. It was also rising to only about 10º above the horizon placing it, much of the time, in the realm of morning clouds, mists, haze, and general murk.

But it’s not over.

While at the time of this writing C/2020 F3 continues to be viewable in the wee hours before dawn in the northeastern sky, sinking lower with each morning, it is now also showing in the post-sunset twilight. It’s still only becoming visible around 14º to 10º above the north-northwestern horizon as it sinks toward the horizon following the Sun. The comet sets around 12:30 AM.

July’s evening sky offers more convenient viewing hours for C/2020 F3. Credit: SkySafari

Evenings, for the next couple of weeks and possibly into August, go comet hunting! Depending upon whether the sky is clear of obstructions, clouds, and haze, skywatchers may be able to see the comet with unaided eye. Good binoculars will help in finding it and will give seekers a better view. The comet will be very low to the horizon so an elevated location will aid in viewing. Use binoculars to look west and then past northwest in the deepening twilight, scanning slowly and just above the horizon. The comet will appear as a vertical streak with a bright dot at the lower end, as in the picture at the top of this page. It may not be spectacular but how many comets does one see in their lifetime?

Our outbound visitor from outer space makes its closest pass by Earth on July 23 when it will be 103.7 million kilometers — about 64 million miles — away returning in roughly 7,000 years.

Little difference can be seen between an earlier stage and the maximum eclipse state of the July 4 - 5, 2020 penumbral lunar eclipse. Photos by James Guilford.

Little difference can be seen between an earlier stage and the maximum eclipse state of the July 4 – 5, 2020 penumbral lunar eclipse. The images were made with identical camera and Photoshop settings. Photos by James Guilford.

There was much ballyhoo surrounding the penumbral lunar eclipse that would take place the night of July 4 – 5, 2020. We joined in just to explain a little about what was going on and what might be expected. Penumbral lunar eclipses take place when the Moon passes through the thin outer shadow Earth casts out into space; they are often very subtle, slight, and in this case, nearly undetectable. Just witness the photo above that shows the Full Buck Moon about one-half hour before maximum eclipse and the Moon at maximum. Casual observers saw no change across the entire event and it’s hard for us to see the difference even in photos that can be made to emphasize features! So we apologize if you waited up to see what we called the  “subtle” eclipse but, if you did, you saw a beautiful Full Moon!

Then there was the much-less-promoted Sunday night, July 5, conjunction of Earth’s Moon, with planets Jupiter and Saturn… a lovely sight! We went out to photograph it an hour after moonrise and spied a brilliant orange Moon lighting up the scattered clouds with Jupiter shining through and Saturn making a somewhat dimmer appearance. A conjunction is when two or more celestial objects appear close together in our skies — emphasis on appear since Moon, Jupiter, and Saturn are separated by hundreds of millions of miles. We were surprised to see, in the photo below, that even Jupiter’s four Galilean Moons can be seen. The stars and planets appear oblong or as short streaks due to Earth’s rotation and the length of the camera exposure.

Conjunction of Earth's Moon, with planets Jupiter (bright dot above), and Saturn (less bright dot to the left at the edge of a cloud), the night of July 5, 2020. Photo by James Guilford.

Conjunction of Earth’s Moon, with planets Jupiter (bright dot above), and Saturn (less bright dot to the left at the edge of a cloud), the night of July 5, 2020. Photo by James Guilford.