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Home , Geology of the Moon, Lunar soil, Lunar station, New Moon, Troctolite 76535

July 2020 The Monthly Newsletter of the Bays Mountain Club

More on Edited by Adam Thanz this image. See FN1 Chapter 1 Cosmic Reflections

William Troxel - BMAC Chair

More on this image. See FN2 William Troxel

More on Cosmic Reflections this image. See FN3

Greetings fellow BMAC’ers! Here we are almost to July 2020. I also wanted to thank everyone for show-n-tell. There are lots of Hope my letter finds you and your family well and safe as the new, new but used and improved items that you are getting. This COVID-19 continues to uproot our lives. More about that later. is great. The show-n-tell feature will be part of our meetings for the upcoming . Be sure and get your stuff together so you First I wanted to thank everyone for joining last ’s online can share with the members. I also want to encourage you once meeting. I think it went very well. We are still learning how to use you have shown the new item to the members don’t forget you Zoom and all the features the program has to offer. I want to can give an update of how the item worked once you had a thank Jon for sharing the update of his personal observatory chance to get it installed and test it out. We all read the reviews progress with the club. I was impressed with how far he has on new things before we buy them, but I personally think it gotten. I thought it was very interesting how he came up with the means more when one of our own club members has the item decisions each step of the build. Jon promised to keep us and does a review. Lets’ face it, the reviews are good information posted and even have us out to the sight once it is completed. I but I do not know those people. I know you. For me, it's "I know am looking forward to that event. Thanks again for letting us see the face behind the name." Thank you for your willingness to your big project. If you are thinking about starting something like share. this please feel free to contact Jon. He can give you some very good advice. I really want to encourage the rest of us to do a I am sure you are all wanting to know about this year's picnic. presentation via an online platform. I have talked about a few There will not be an *organized* picnic this year. I am not telling ways that you can do it. YouTube or just pictures of your projects you as an individual person or family that you can not go out and are two ways. If you want to be a meeting speaker, please let me just happen to run into another club member. If you choose to do know. I will get on it. I have lots of openings. Call or text me. this on your own, please be safe. Practice all the safety measures that have been recommended by the CDC and the

Bays Mountain Astronomy Club Newsletter July 2020 3 WHO. Wear masks, keep at least 6' apart, meet outside and do not share anything including food, utensils, plates, etc. While I can not know when we will be able to be physically together and do things as a club again, I believe that at some point we will be able to be a more social club. Until that time, please be safe and remember we are getting through this pandemic together. I am working for future events and ideas that we can do as a club.

Until next time, Be Safe and Clear Skies….

4 Bays Mountain Astronomy Club Newsletter July 2020 Chapter 2 Celestial Happenings

Jason Dorfman

More on this image. See FN5 Jason Dorfman

More on Celestial Happenings this image. See FN3

With July upon us, summer has officially arrived. As we all know, p.m. and , laying just 6° east of , will rise just 25 it is sure to be an odd summer with the current state of things. minutes later. The two will climb to around 15° high in the SE Though the nights are short, I hope that many of you are perhaps shortly after 11 p.m. Jupiter shines brightly at magnitude -2.7 in taking advantage of the rare clear night to do some observing. the constellation of , about 10° east of the handle As July begins, the sets just before 9 p.m. with the dark, stars of the Teapot. Saturn is a bit dimmer at magnitude -0.1 in star-filled skies not appearing until nearly 11 p.m. However, some , just along its border with Sagittarius. late night observing will bring its rewards as both Jupiter and Jupiter will reach opposition first in the early morning hours of Saturn will reach opposition this month. Plus, we are catching up the 14th. Prime observing will occur when the planet reaches its to Mars, so the views of the Red Planet are also improving. If highest altitude due south at 1:30 a.m. Due to opposition you’re more of an early riser, you’ll still catch views of Mars, occurring during a summer month when the is low in the Jupiter and Saturn while adding Venus and even in the night sky, Jupiter will be just 32° above the southern horizon at third of July. Sunrise progresses from 6:15 a.m. to 6:36 its highest. Telescopes will reveal the disk of the planet spanning a.m. over the month, so the dark predawn skies will begin to about 48”. Saturn reaches opposition not quite a week later, in brighten a little before 5 a.m. the early evening of the 20th. It will be at its highest due south Planets also at 1:30 a.m. and just slightly higher than Jupiter at an As the Sun sets and the sky begins to darken, a waxing gibbous altitude of 33°. The planet spans 19” while the ring plane extends sits at the head of the scorpion. Jupiter is just peaking out to 42” and is tilted 21°. above the horizon in the southeast. The gas giants are the Next up is the Red Planet, Mars, shining at magnitude -0.5. It will planetary highlights for July as they both will reach opposition rise just after 1 a.m. on the 1st and will rise to about 15° high an and thus prime observing. On the 1st, Jupiter rises just after 9:30 hour and a half later. It will climb to almost 45° above the SE

Bays Mountain Astronomy Club Newsletter July 2020 6 horizon an hour before sunrise. Mars is moving through the occurs on July 5th when the Moon will be about 11° southern section of the constellation this month, though it west and a little south of Jupiter. On the following night, the Moon will skim through the northwest corner of Cetus from the 8th to will lie between and slightly south of Jupiter and Saturn. Look for the 26th. The disk of Mars continues to grow as continues a nearly 3rd quarter Moon passing just south of Mars in the to catch up to the Red Planet. It will increase from 12” to 15” over second week of July, On the 11th, it will about 7° to the SW of the month, while appearing about 85% illuminated. By month's Mars and about 5° east of Mars on the following night. end, Mars will rise just before midnight and will ascend to a little occurs on the 22nd, just two days after Saturn reaches over 55° high and almost due south an hour before sunup. opposition. As we approach the end of the month we’ll see the Moon return to our early evening skies. Look for a thin, 2- old In the early morning hours just as the first light of dawn is about 3° NE of Regulus on the evening of the 22nd. beginning to brighten the eastern sky, you can spot Venus rising just north of east. Just after 5 a.m. it will be 10° high and shining That’s all for this month. I hope you’re all well and staying safe. brilliantly at magnitude -4.6. Venus sits just above the Hyades star Have fun observing! cluster in . Though traveling eastward against the background stars, Venus is appearing to move further from the Sun as it heads towards its greatest western elongation in the second week of August. Keep an eye on it during the second week of July as it passes by , getting as close as 1° on the 12th. On the morning of the 17th, a thin sliver of a waning crescent Moon will be about 3.5° to the left of Venus.

As we watch Venus swing around in its orbit and away from Earth this month, telescopic views will reveal the disk shrinking from 43” to 27”, the phase, however, will increase from 19% to 43% illumination.

Luna

7 Bays Mountain Astronomy Club Newsletter July 2020 Chapter 3 The Queen Speaks Robin Byrne Robin Byrne

More on Happy Birthday this image. See FN3

This month, we celebrate the life of a man whose varied careers Schmitt who went to work for the U. S. ’s have taken him many places, including the Moon! Harrison Astrogeology Center in Flagstaff, Arizona. With the space Hagan Schmitt (Jack to his friends) was born July 3, 1935 in program now focused on going to the Moon, Jack helped Santa Rita, New Mexico, and grew up in Silver City, NM, where develop geological field techniques the astronauts could use on he went to Western High School. the lunar surface. Part of the job included mapping of the Moon, as well as, training the astronauts while on geological field trips. After graduating high school in 1953, Jack went to the California That same year, Jack heard that the National Academy of Institute of Technology, where he majored in . He Sciences was looking for people to volunteer to be scientist- graduated in 1957 with a Bachelors of Science degree. For the astronauts. Jack said in an interview, "I thought about 10 next year, Jack lived in Oslo, Norway, working for the Norwegian seconds and raised my hand and volunteered. Primarily because Geological Society, studying the geology of Norway’s west I felt—I can remember feeling, at the time, that if I didn’t coast, while attending the University of Oslo. He then returned to volunteer, no matter what happened to my application, that I'd the United States to attend Harvard University, where, while almost certainly regret it when human beings actually went to the working on his doctorate, he taught a course on ore deposits. Dr. Moon.” Schmitt received his PhD in geology in 1964, with a dissertation based on the work he conducted in Norway. In June of 1965, Dr. Schmitt was selected by NASA as part of a group of scientist-astronauts. This was the first time astronauts Upon graduation, Jack, in the hopes of getting a job, wrote to were chosen who weren’t test pilots, so that meant they needed Eugene Shoemaker, the lead training astronauts for the to learn to fly. For the next year, Jack and his fellow scientist- upcoming lunar missions. Shoemaker was actually going to astronauts trained at Williams Air Force Base in Arizona. There contact Jack to offer him a position because of Jack’s superb U. they learned to be jet pilots. Dr. Schmitt ultimately logged over S. Geological Survey exam results. So it was that Dr. Harrison

Bays Mountain Astronomy Club Newsletter July 2020 9 Harrison H. Schmitt astronaut. Image from NASA - 1971

10 Bays Mountain Astronomy Club Newsletter July 2020 During the first EVA of 17, Eugene Cernan photographed Harrison Schmitt with the American flag and the Earth (400 000km away) in the background. The chest- mounted RCU and the camera bracket are clearly visible. Cernan is visible in the reflection in Schmitt's helmet visor in the awkward position he assumed to obtain this image. Image from NASA - Dec. 12, 1972

11 Bays Mountain Astronomy Club Newsletter July 2020 Geologist-Astronaut Harrison Schmitt, lunar module pilot, uses an adjustable sampling scoop to retrieve lunar samples during the second extravehicular activity (EVA-2), at Station 5 at the Taurus-Littrow landing site. The cohesive nature of the lunar is born out by the "dirty" appearance of Schmitt's space suit. A gnomon is atop the large in the foreground. The gnomon is a stadia rod mounted on a tripod, and serves as an indicator of the gravitational vector and provides accurate vertical reference and calibrated length for determining size and position of objects in near-field photographs. The color scale of blue, orange and green is used to accurately determine color for photography. The rod of it is 18 inches long.The scoop Dr. Schmitt is using is 11 3/4 inches long and is attached to a tool extension which adds a potential 30 inches of length to the scoop. The pan portion, blocked in this view, has a flat bottom, flanged on both sides with a partial cover on the top. It is used to retrieve sand, dust and lunar samples too small for the tongs. The pan and the adjusting mechanism are made of stainless steel and the handle is made of aluminum. Image from NASA - Dec. 13, 1972

12 Bays Mountain Astronomy Club Newsletter July 2020 Adam Thanz, Harrison Schmitt & Robin Byrne. Image by Yolanda Korff - Aug. 2, 2015

13 Bays Mountain Astronomy Club Newsletter July 2020 2100 hours of flight time, with 1600 hours in jets. later, Eugene Cernan and Harrison Schmitt became the last two people to and walk on the Moon. During their three days on Once the pilot training was complete, Dr. Schmitt returned to the lunar surface, Schmitt collected one of the most interesting NASA, again performing duties related to training the other lunar samples, 76535, which is the oldest, unaltered astronauts in geologic techniques to use on the Moon. Once the lunar rock brought back from the missions. It also holds evidence lunar landing missions began, Jack helped in the study of the that the Moon once had a magnetic field. The region where they lunar rock samples that were brought back and participated in landed, Taurus-Littrow, was thought to have once been a region debriefing the crews about their observations of the Moon’s of volcanic activity. Proof of was found by Schmitt surface. when he discovered “orange glass” in the soil, which was likely In March 1970, Jack Schmitt became the first of the scientist- caused by volcanic activity. Describing what it looked like on the astronauts to be assigned to a crew. Along with Richard Gordon Moon, Schmitt said in an interview, "The orange soil never looks and Vance Brand, Schmitt was assigned to the back-up crew for as orange to you in a picture as it did to us while we were on the . During this time, Schmitt, as the back-up Lunar Moon.” In addition to achieving scientific breakthroughs, Schmitt Module Pilot, learned all he could about both the Command and Cernan also had moments of levity while on the Moon, Module and the Lunar Module. The way crews were assigned, the including singing “While Strolling Through the Park One Day,” but back-up crews would then be the prime crew 3 missions later, changing “park” in the lyrics to “Moon.” On December 19, the meaning that Schmitt would be flying on Apollo 18. However, due Apollo 17 crew returned safely to Earth and brought the Apollo to budget cuts, Apollo’s 18 and 19 were cancelled. The scientific program to an end. As the last, and most ambitious of the Apollo community pressured NASA to include a scientist-astronaut on at missions, Apollo 17 set many records: Longest lunar mission least one mission before the program ended. Although Deke flight (301 hours), longest time spent walking on the Moon (a total Slayton, head of the Astronaut Office, had already assigned of 22 hours over the course of 3 excursions), and most lunar Eugene Cernan, Joe Engle, and Ron Evans as the crew for Apollo samples returned (250 pounds). 17, he was pressed to make a switch. So Harrison Schmitt After the conclusion of his mission, Jack continued to work for replaced Joe Engle as the Lunar Module Pilot for Apollo 17. NASA, documenting the returned samples and geologic On December 7, 1972, Apollo 17 launched from the Kennedy discoveries. He continued on in a variety of administrative Space Center and began their journey to the Moon. Four days positions, too, including organizing the Energy Program Office,

14 Bays Mountain Astronomy Club Newsletter July 2020 Chief of Scientist-Astronauts, and Assistant Administrator for also a member of the Planetary Society. In 2008, he resigned from Energy Programs. That last position included coordinating both. In the case of the Planetary Society, he cited a difference of support from NASA to other agencies that were applying opinion regarding their push for manned exploration of Mars aeronautics and other space technologies to various aspects of (Schmitt prefers a return to the Moon) and their stance on global the energy industry on Earth. warming. Schmitt has been a vocal proponent of the idea that climate change is due to natural, rather than man-made, factors, In August, 1975, Dr. Schmitt retired from NASA to pursue believing that the issue has been manufactured for political something he had always felt compelled to do: run for political purposes. office. Harrison Schmitt ran for the U. S. Senate, representing New Mexico, and was elected in 1976. For the next 6 , Currently, Dr. Schmitt splits his time between his homes in New Schmitt represented his home state, and served on a variety of Mexico and Minnesota. In 2006, he wrote a book titled “Return to committees, including: Chairman of the Science, Technology, and the Moon: Exploration, Enterprise, and Energy in the Human Space Subcommittee, as well as a member of the Commerce, Settlement of Space.” He is involved in local civic projects, and Banking, Appropriations, Intelligence, and Ethics Committees. enjoys a variety of outdoor activities, including skiing, fishing, and Despite his successful time as a senator, he was criticized for not hiking. focusing enough on local issues, and was defeated in his run for I had the great fortune to meet Dr. Schmitt at a planetarium reelection in 1982. conference in 2015, where he was the keynote speaker. I was After leaving politics, Schmitt remained active in a wide variety of most impressed with how generous he was with his time, talking ways. He has worked as a consultant in areas related to business, with everyone after the presentation, and happily posing for geology, space, and public policy. He has held a teaching pictures with anyone who asked. We all avoided discussing position at the University of Wisconsin, teaching a course about climate change, but, instead, focused on his astronaut career. resources from space. In 1997, Schmitt proposed an initiative Whether you agree with his views or not, Harrison “Jack” Schmitt titled Interlune InterMars, in support of mining the Moon for has led a life full of noteworthy accomplishments, and for that we -3 to be used in fusion reactors. can wish him the happiest of birthdays.

In 2005, Schmitt was named chair of the NASA Advisory Council, References: providing technical advice to the NASA Administrator. He was

15 Bays Mountain Astronomy Club Newsletter July 2020 Harrison Schmitt - Wikipedia - https://en.wikipedia.org/wiki/ Harrison_Schmitt

Biographical Data Lyndon B. Johnson Space Center Harrison H. Schmitt - https://www.nasa.gov/sites/default/files/atoms/files/ schmitt_harrison.pdf

Harrison Schmitt: Geologist on the Moon by Elizabeth Howell, April 23, 2013 - https://www.space.com/20789-harrison-schmitt- astronaut-biography.html

16 Bays Mountain Astronomy Club Newsletter July 2020 Chapter 4 Space Place

More on this image. See FN6 David Prosper

Mars’s Latest Visitor: NASA’s Perseverance Rover More on this image. See FN3

NASA’s latest Mars rover, Perseverance, is launching later this study with its unique caching system. Future missions will month! This amazing robot explorer will scout the surface of retrieve these samples from the rover and return them for Mars for possible signs of ancient life and collect soil samples for detailed study by scientists on Earth. Perseverance also carries return to Earth by future missions. It will even carry the first off- two microphones so we can hear the sounds of Mars and the planet helicopter: Ingenuity. Not coincidentally, Perseverance will noises of its instruments at work. It will even launch a small be on its way to the red planet just as Mars dramatically helicopter - Ingenuity - into the Martian as a trial for increases in brightness and visibility to eager stargazers as our future aerial exploration! planets race towards their closest approach in October of this Would you like to contribute to Mars mission science? You can year. help NASA’s rover drivers safely navigate the Martian surface by Perseverance’s engineers built upon the success of its contributing to the AI4Mars project! Use this tool to label terrain engineering cousin, Curiosity, and its design features many features on photos taken of the Martian surface by NASA unique upgrades for a new science mission! In February of 2021, missions to help train an artificial intelligence algorithm to better Perseverance will land at the site of an ancient river delta inside read their surrounding landscape: https://bit.ly/AI4Mars of Jezero Crater and ready its suite of seven primary scientific The launch of Mars Perseverance is, as of this writing, scheduled instruments. The rover will search for traces of past life, including for July 20, 2020 at 9:15 a.m. EDT. More details, updates, and possible Martian fossils, with WATSON and SHERLOC, two livestreams of the event are available on NASA’s official launch advanced cameras capable of seeing tiny details. The rover also page: https://bit.ly/Mars2020Launch. Dig deep into the science carries an amazing instrument, SuperCam, to blast rocks and of the Mars 2020 mission and the Perseverance rover at: https:// soil outside of the rover’s reach with lasers to determine their mars..gov/mars2020/. Find out even more about past, chemical makeup with its onboard suite of cameras and present, and future Mars missions at https://nasa.gov. spectrometers. Perseverance will also take core samples of some of the most promising rocks and soil, storing them for later

Bays Mountain Astronomy Club Newsletter July 2020 18 More on this image. See FN8

19 Bays Mountain Astronomy Club Newsletter July 2020 More on this image. See FN9

20 Bays Mountain Astronomy Club Newsletter July 2020 This article is distributed by NASA Night Sky Network. The Night Sky Network program supports astronomy clubs across the USA dedicated to astronomy outreach. Visit https:// nightsky.jpl.nasa.gov to find local clubs, events, and more!

21 Bays Mountain Astronomy Club Newsletter July 2020 Chapter 5 BMAC and more

More on this image. See FN7 More on BMAC Calendar and more this image. See FN3

Date Time Location Notes

BMAC Meetings

Friday, August 7, 2020 7 p Via Zoom Program TBA.

Friday, September 4, 2020 7 p Via Zoom Program TBA.

Friday, October 2, 2020 7 p Via Zoom Program TBA.

SunWatch

Every Saturday & Sunday Cancelled until further notice. View the Sun safely with a white-light view if clear.; Free. March - October

StarWatch

October 3, 10, 2020 7:30 p

Cancelled until further notice. View the night sky with large telescopes. If poor , an alternate live tour October 17, 24, 31, 2020 7 p of the night sky will be held in the planetarium theater.; Free. If you are a club member and have completed the Park volunteer program, you are welcome to help out with this public program. Please show up at least 30 minutes prior to the official start time. November 7, 14, 21, 28, 2020 6 p

Bays Mountain Astronomy Club Newsletter July 2020 23 Bays Mountain Astronomy Club Regular Contributors:

853 Bays Mountain Park Road William Troxel

Kingsport, TN 37650 William is the current chair of the club. He enjoys everything to do with astronomy, (423) 229-9447 including sharing this exciting and interesting hobby with anyone that will www.BaysMountain.com listen! He has been a member since 2010. [email protected] Robin Byrne

Robin has been writing the science history column since 1992 and was chair in 1997. She is an Associate Professor of Annual Dues: Astronomy & Physics at Northeast State Community College (NSCC). Dues are supplemented by the Bays Mountain Park Association and volunteerism by the club. As such, our dues can be kept at a very low cost. Jason Dorfman $16 /person/year Jason works as a planetarium creative and $6 /additional family member technical genius at Bays Mountain Park. He has been a member since 2006. Note: if you are a Park Association member (which incurs an additional fee), then a 50% reduction in BMAC dues are applied. Adam Thanz

The club’s website can be found here: Adam has been the Editor for all but a number of since 1992. He is the https://www.baysmountain.com/astronomy/astronomy- Planetarium Director at Bays Mountain club/#newsletters Park as well as an astronomy adjunct for NSCC.

Bays Mountain Astronomy Club Newsletter July 2020 24 Section 3

More on Footnotes this image. See FN3

miles across) orbits outside the rings on the right of the image. The small moon Atlas (30 Footnotes: kilometers, 19 miles across) orbits inside the thin F ring on the right of the image. The brightnesses of all the , relative to the planet, have been enhanced between 30 and 60 1. The Rite of Spring times to make them more easily visible. Other bright specks are background stars. Spokes -- ghostly radial markings on the B ring -- are visible on the right of the image. Of the countless equinoxes Saturn has seen since the birth of the solar system, this one, captured here in a mosaic of light and dark, is the first witnessed up close by an emissary from This view looks toward the northern side of the rings from about 20 degrees above the ring plane. Earth … none other than our faithful robotic explorer, Cassini. The images were taken on Aug. 12, 2009, beginning about 1.25 days after exact equinox, using Seen from our planet, the view of Saturn’s rings during equinox is extremely foreshortened and the red, green and blue spectral filters of the wide angle camera and were combined to create this limited. But in orbit around Saturn, Cassini had no such problems. From 20 degrees above the natural color view. The images were obtained at a distance of approximately 847,000 kilometers ring plane, Cassini’s wide angle camera shot 75 exposures in for this mosaic showing (526,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 74 degrees. Saturn, its rings, and a few of its moons a day and a half after exact Saturn equinox, when the Image scale is 50 kilometers (31 miles) per pixel. sun’s disk was exactly overhead at the planet’s equator. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and The novel illumination geometry that accompanies equinox lowers the sun’s angle to the ring the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of plane, significantly darkens the rings, and causes out-of-plane structures to look anomalously Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, bright and to cast shadows across the rings. These scenes are possible only during the few Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed months before and after Saturn’s equinox which occurs only once in about 15 Earth years. Before and assembled at JPL. The imaging operations center is based at the Space Science Institute in and after equinox, Cassini’s cameras have spotted not only the predictable shadows of some of Boulder, Colo. Saturn’s moons (see PIA11657), but also the shadows of newly revealed vertical structures in the For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov/. The rings themselves (see PIA11665). Cassini imaging team homepage is at http://ciclops.org. Also at equinox, the shadows of the planet’s expansive rings are compressed into a single, Image Credit: NASA/JPL/Space Science Institute narrow band cast onto the planet as seen in this mosaic. (For an earlier view of the rings’ wide shadows draped high on the northern hemisphere, see PIA09793.) 2. Rising The images comprising the mosaic, taken over about eight hours, were extensively processed before being joined together. First, each was re-projected into the same viewing geometry and A sky filled with stars and a thin veil of clouds. then digitally processed to make the image “joints” seamless and to remove lens flares, radially Image by Adam Thanz extended bright artifacts resulting from light being scattered within the camera optics. At this time so close to equinox, illumination of the rings by sunlight reflected off the planet vastly 3. The Cat's Eye Nebula, one of the first planetary nebulae discovered, also has one of the most dominates any meager sunlight falling on the rings. Hence, the half of the rings on the left complex forms known to this kind of nebula. Eleven rings, or shells, of gas make up the Cat's illuminated by is, before processing, much brighter than the half of the rings on the Eye. right. On the right, it is only the vertically extended parts of the rings that catch any substantial sunlight. Credit: NASA, ESA, HEIC, and The Hubble Heritage Team (STScI/AURA) With no enhancement, the rings would be essentially invisible in this mosaic. To improve their Acknowledgment: R. Corradi (Isaac Newton Group of Telescopes, Spain) and Z. Tsvetanov visibility, the dark (right) half of the rings has been brightened relative to the brighter (left) half by a (NASA) factor of three, and then the whole ring system has been brightened by a factor of 20 relative to the planet. So the dark half of the rings is 60 times brighter, and the bright half 20 times brighter, 4. Jupiter & Ganymede than they would have appeared if the entire system, planet included, could have been captured in a single image. NASA's Hubble Space Telescope has caught Jupiter's moon Ganymede playing a game of "peek- a-boo." In this crisp Hubble image, Ganymede is shown just before it ducks behind the giant The moon Janus (179 kilometers, 111 miles across) is on the lower left of this image. Epimetheus planet. (113 kilometers, 70 miles across) appears near the middle bottom. Pandora (81 kilometers, 50

Bays Mountain Astronomy Club Newsletter July 2020 25 Ganymede completes an orbit around Jupiter every seven days. Because Ganymede's orbit is Hubble couldn't directly view the planets, but instead employed a powerful search technique tilted nearly edge-on to Earth, it routinely can be seen passing in front of and disappearing behind where the telescope measures the slight dimming of a star due to the passage of a planet in front its giant host, only to reemerge later. of it, an event called a transit. The planet would have to be a bit larger than Jupiter to block Composed of rock and ice, Ganymede is the largest moon in our solar system. It is even larger enough light — about one percent — to be measurable by Hubble; Earth-like planets are too small. than the planet Mercury. But Ganymede looks like a dirty snowball next to Jupiter, the largest However, an outside observer would have to watch our Sun for as long as 12 years before ever planet in our solar system. Jupiter is so big that only part of its Southern Hemisphere can be seen having a chance of seeing Jupiter briefly transit the Sun's face. The Hubble observation was in this image. capable of only catching those planetary transits that happen every few days. This would happen if Hubble's view is so sharp that astronomers can see features on Ganymede's surface, most the planet were in an orbit less than 1/20 Earth's distance from the Sun, placing it even closer to notably the white , Tros, and its system of rays, bright streaks of material blasted from the star than the scorched planet Mercury — hence the name "hot Jupiter." the crater. Tros and its are roughly the width of Arizona. Why expect to find such a weird planet in the first place? The image also shows Jupiter's Great Red Spot, the large eye-shaped feature at upper left. A Based on radial-velocity surveys from ground-based telescopes, which measure the slight wobble storm the size of two , the Great Red Spot has been raging for more than 300 years. in a star due to the small tug of an unseen companion, astronomers have found nine hot Hubble's sharp view of the gas giant planet also reveals the texture of the clouds in the Jovian in our local stellar neighborhood. Statistically this means one percent of all stars should have such atmosphere as well as various other storms and vortices. planets. It's estimated that the orbits of 10 percent of these planets are tilted edge-on to Earth and Astronomers use these images to study Jupiter's upper atmosphere. As Ganymede passes behind so transit the face of their star. the giant planet, it reflects sunlight, which then passes through Jupiter's atmosphere. Imprinted on In 1999, the first observation of a transiting planet was made by ground-based telescopes. The that light is information about the gas giant's atmosphere, which yields clues about the properties planet, with a 3.5-day period, had previously been detected by radial-velocity surveys, but this was of Jupiter's high-altitude haze above the cloud tops. a unique, independent confirmation. In a separate program to study a planet in these revealing This color image was made from three images taken on July 9, 2007, with the Wide Field Planetary circumstances, Ron Gilliland (STScI) and lead investigator Tim Brown (National Center for Camera 2 in red, green, and blue filters. The image shows Jupiter and Ganymede in close to Atmospheric Research, Boulder, CO) demonstrated Hubble's exquisite ability to do precise natural colors. photometry — the measurement of brightness and brightness changes in a star's light — by also looking at the planet. The Hubble data were so good they could look for evidence of rings or Earth- Credit: NASA, ESA, and E. Karkoschka (University of Arizona) sized moons, if they existed. But to discover new planets by transits, Gilliland had to crowd a lot of stars into Hubble's narrow 5. 47 Tucanae field of view. The ideal target was the magnificent southern globular star cluster 47 Tucanae, one of In the first attempt to systematically search for "extrasolar" planets far beyond our local stellar the closest clusters to Earth. Within a single Hubble picture Gilliland could observe 35,000 stars at neighborhood, astronomers probed the heart of a distant globular star cluster and were surprised once. Like making a time-lapse movie, he had to take sequential snapshots of the cluster, looking to come up with a score of "zero". for a telltale dimming of a star and recording any light curve that would be the true signature of a planet. To the fascination and puzzlement of planet-searching astronomers, the results offer a sobering counterpoint to the flurry of planet discoveries announced over the previous months. Based on statistics from a sampling of planets in our local stellar neighborhood, Gilliland and his co-investigators reasoned that 1 out of 1,000 stars in the globular cluster should have planets that "This could be the first tantalizing evidence that conditions for planet formation and evolution may transit once every few days. They predicted that Hubble should discover 17 hot Jupiter-class be fundamentally different elsewhere in the galaxy," says Mario Livio of the Space Telescope planets. Science Institute (STScI) in Baltimore, MD. To catch a planet in a several-day orbit, Gilliland had Hubble's "eagle eye" trained on the cluster The bold and innovative observation pushed NASA Hubble Space Telescope's capabilities to its for eight consecutive days. The result was the most data-intensive observation ever done by limits, simultaneously scanning for small changes in the light from 35,000 stars in the globular star Hubble. STScI archived over 1,300 exposures during the observation. Gilliland and Brown sifted cluster 47 Tucanae, located 15,000 light-years (4 kiloparsecs) away in the southern constellation through the results and came up with 100 variable stars, some of them eclipsing binaries where the Tucana. companion is a star and not a planet. But none of them had the characteristic light curve that Hubble researchers caution that the finding must be tempered by the fact that some astronomers would be the signature of an extrasolar planet. always considered the ancient globular cluster an unlikely abode for planets for a variety of There are a variety of reasons the globular cluster environment may inhibit planet formation. 47 reasons. Specifically, the cluster has a deficiency of heavier elements that may be needed for Tucanae is old and so is deficient in the heavier elements, which were formed later in the universe building planets. If this is the case, then planets may have formed later in the universe's evolution, through the nucleosynthesis of heavier elements in the cores of first-generation stars. Planet when stars were richer in heavier elements. Correspondingly, life as we know it may have appeared surveys show that within 100 light-years of the Sun, heavy-element-rich stars are far more likely to later rather than sooner in the universe. harbor a hot Jupiter than heavy-element-poor stars. However, this is a chicken and egg puzzle Another caveat is that Hubble searched for a specific type of planet called a "hot Jupiter," which is because some theoreticians say that the heavy-element composition of a star may be enhanced considered an oddball among some planet experts. The results do not rule out the possibility that after if it makes Jupiter-like planets and then swallows them as the planet orbit spirals into the star. 47 Tucanae could contain normal solar systems like ours, which Hubble could not have detected. The stars are so tightly compacted in the core of the cluster – being separated by 1/100th the But even if that's the case, the "null" result implies there is still something fundamentally different distance between our Sun and the next nearest star — that gravitational tidal effects may strip between the way planets are made in our own neighborhood and how they are made in the cluster. nascent planets from their parent stars. Also, the high stellar density could disturb the subsequent migration of the planet inward, which parks the hot Jupiters close to the star. 26 Bays Mountain Astronomy Club Newsletter July 2020 Another possibility is that a torrent of light from the earliest and biggest stars, which formed in the cluster billions of years ago may have boiled away fragile embryonic dust disks out of which planets would have formed. These results will be published in The Astrophysical Journal Letters in December. Follow-up observations are needed to determine whether it is the initial conditions associated with planet birth or subsequent influences on evolution in this heavy-element-poor, crowded environment that led to an absence of planets. Credits for Hubble image: NASA and Ron Gilliland (Space Telescope Science Institute)

6. Space Place is a fantastic source of scientific educational materials for children of all ages. Visit them at: http://spaceplace.nasa.gov

7. NGC 3982 Though the universe is chock full of spiral-shaped galaxies, no two look exactly the same. This face-on spiral galaxy, called NGC 3982, is striking for its rich tapestry of star birth, along with its winding arms. The arms are lined with pink star-forming regions of glowing , newborn blue star clusters, and obscuring dust lanes that provide the raw material for future generations of stars. The bright nucleus is home to an older population of stars, which grow ever more densely packed toward the center. NGC 3982 is located about 68 million light-years away in the constellation Ursa Major. The galaxy spans about 30,000 light-years, one-third of the size of our Milky Way galaxy. This color image is composed of exposures taken by the Hubble Space Telescope's Wide Field Planetary Camera 2 (WFPC2), the Advanced Camera for Surveys (ACS), and the Wide Field Camera 3 (WFC3). The observations were taken between March 2000 and July 2009. The rich color range comes from the fact that the galaxy was photographed invisible and near-infrared light. Also used was a filter that isolates hydrogen emission that emanates from bright star-forming regions dotting the spiral arms. Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA) Acknowledgment: A. Riess (STScI)

8. Perseverance inspects a cluster of interesting Martian rocks with its instruments in this artist rendering by NASA JPL/Caltech

9. Observe Mars yourself over the next few months! Mars can be found in early morning skies throughout July, and by the end of the month will rise before midnight. Mars gradually brightens every night until the close approach of Mars in October. The pre-dawn skies of July 17 present an especially nice view, as the waning crescent Moon will appear near Venus and Aldebaran.

27 Bays Mountain Astronomy Club Newsletter July 2020