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[TomT]

Download the attached mp3 audio file to play.  46 minutes with the advertisements cropped out.  Sorry, between 15-18 minutes in, I mistakenly was playing a video from the Saturday, November 21, 2020 SpaceX launch and recovery of the Falcon 9 rocket, so voices from that are on top of the radio show.  But listen closely to this and you can hear the sonic boom that happened shortly after the rocket 1st stage touched down.   The breaking of the sound barrier was probably 10 miles up, so that would reach the ground about 50 seconds later, after the rocket had landed.  I will post that video at https://www.youtube.com/channel/UCU0r4RxzoyT_pwNcfN5aJsA/videos soon.

On 11/21/2020 11:04 PM, Jerry wrote this list of possible subjects to discuss:

>Monday, November 23
>    The Moon passes 5° south of Neptune at 4 A.M. PST, but both are below the horizon at the time. Instead, you can catch the pair after sunset, when they are just over 6° apart in the constellation Aquarius.
>    Neptune, whose dim magnitude 8 glow will require binoculars or a small scope, presents a bluish disk just 2" across. It currently sits less than 1° east of magnitude 4.2 Phi (φ) Aquarii. Neptune is now roughly 30 astronomical units from Earth, where 1 astronomical unit, or AU, is the average Earth-Sun distance, and a fraction of an AU is now doing this show. That means its light takes a little over four hours to reach us here on Earth. Neptune has been slowly sliding southwest against the background stars, but in just a few days it will reach its stationary point and about-face to begin tracking northeast.
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> Tuesday, November 24
>    Starting an hour before sunrise, both Mercury and Venus should be easy to spot in the brightening sky. Mercury, just rising among the stars of Libra, is an easy magnitude –0.7. Venus is impossible to miss at magnitude –4. It’s sitting less than 2° from magnitude 4 Kappa (κ) Virginis and is now 10° due east of bright Spica.
>    Through a telescope, Mercury appears 90 percent illuminated and 5" across. It is just 0.5° from Nu (ν) Librae, whose dim, magnitude 5 glow will fade quickly as dawn approaches. Venus is a much larger 12" across, with a disk that’s 87 percent lit.
>    See how long you can follow the planets into the morning sky, but take care — stop using any optical equipment, including binoculars, at least several minutes before sunrise to avoid accidentally damaging your eyes.
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> Wednesday, November 25
>    The Moon passes 5° south of Mars at 12 P.M. PST. By sunset, our satellite is just 5.2° from the Red Planet. Mars remains in Pisces the Fish, while the Moon is south-southwest of the planet, just over the border in Cetus the Whale.
>    Let full darkness fall, then swing your scope to Mars to observe its 15"-wide disk, which shines at magnitude –1.3. Around 8 P.M. EST, the bright spot of Olympus Mons is visible on the disk; it will rotate out of view over the next two hours or so. The dark swaths of first Mare Sirenum, and later Mare Cimmerium, are also visible south of Olympus Mons.
>    NASA’s Mars 2020 mission is now less than 100 days from its landing on Mars. Recently, mission scientists released audio recorded by the Perseverance rover’s microphones as it travels through deep space. The sound is generated by mechanical vibrations that the microphone’s equipment has turned into an electrical signal. The soft buzz comes from the rover’s heat rejection fluid pump, which maintains the equipment’s temperature even in frigid cold.
> Perseverance Rover's Interplanetary Sounds  https://soundcloud.com/nasa/perseverance-rover-sounds
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> Thursday, November 26
>    The Moon reaches the farthest point from Earth in its orbit around our planet, called apogee, at 4:29 P.M. PST. At that time, our satellite will sit 252,211 miles (405,894 km) from Earth.
>    With our satellite visible all evening, it’s a great time to explore its pockmarked face. You’ll find the Moon in the southeastern corner of Pisces the Fish, now nearly 13° east of Mars. As the Moon travels around Earth, it can look to observers on Earth as if it’s “nodding” back and forth — sometimes areas at the limb are easier to see than others. This motion is called libration and tonight, it makes features normally hard to spot on the Moon’s northeastern limb more accessible. With binoculars or a small scope, look at the upper right portion of the lunar disk for three dark spots. These are Lacus Spei, Endymion, and Mare Humboldtianum (closest to the edge).
>    Come back over the next few nights, and you’ll see Humboldtianum slowly disappear in the last days of the month. By the 30th, Lacus Spei and Endymion will appear at the very edge of the disk.
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> Friday, November 27
>    Since last night, the Moon has crossed out of Pisces and traveled through the corner of Cetus, where it passed 3° south of Uranus at noon EST. By sunset in the Midwest, our satellite is now in Aries, about 4.5° southeast of the ice giant.
>    Uranus, currently magnitude 5.7, is visible in binoculars but may be hard to spot against our satellite’s glare. Just over 14° north-northwest of the Moon is Hamal, the Ram’s brightest star; 9.5° southeast is Menkar in Cetus the Whale. Look east-northeast of the Moon to find the Pleiades (M45); how many stars can you see without optical aid? Most observers can easily see five, but seven are visible for those with sharp eyes or dark skies. For the latter, you’ll need to wait a few more nights to give the Moon time to move away from the region. Some experienced naked-eye observers have seen 10 or more stars in this open cluster under the right conditions.
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> Scientists have uncovered new evidence in the mysterious fluorescent debris of the Blue Ring Nebula that may explain how the strange structure formed.
>    The Blue Ring Nebula is a planetary nebula that harbors a central star, known as TYC 2597-735-1. An unusual ultraviolet ring surrounds the star, which astronomers first observed in 2004 using NASA's now-defunct Galaxy Evolution Explorer (GALEX) space telescope. Until now, the formation of this peculiar ring — which is actually invisible ultraviolet light that has been color-coded blue in the telescope images — has largely remained a mystery.
>    “Every time we thought we had this thing figured out, something would tell us, 'No, that's not right,'" Mark Seibert, an astrophysicist with the Carnegie Institution for Science, a member of the GALEX team and a co-author on the new research, said in a statement. "That's a scary thing as a scientist. But I also love how unique this object is, and the effort that so many people put in to figure it out."
https://phys.org/news/2020-11-mysterious-blue-nebula-scientists-fate.html
>    The Blue Ring Nebula is believed to have formed after a stellar collision, which ejected a cloud of hot debris into space. These emissions appear to form a ring around the nebula's central star, as the outflow of material forms a cone shape and the base of one of the cones is oriented almost directly toward Earth.
(Image credit: NASA/JPL-Caltech/M. Seibert (Carnegie Institution for Science)/K. Hoadley (Caltech)/GALEX Team)
>    Using the W. M. Keck Observatory in Hawaii, researchers found that the blue ring is actually the base of a cone-shaped cloud of glowing molecular hydrogen that extends away from the central star, toward Earth. The new observations also show a second cone-shaped cloud that extends from the star in the opposite direction.
>    The bases of the cone-shaped clouds appear to overlap when viewed from Earth, creating the ring shape around the star, Christopher Martin, a physicist at the California Institute of Technology (Caltech) and former principal investigator of GALEX, said in a news conference held digitally on Tuesday (Nov. 17), before the research was made public.
>    The scientists behind the new research believe that the clouds of fluorescent debris formed after a sunlike star collided with and consumed a smaller stellar companion only a few thousand years ago. The recent observations capture a never-before-seen evolutionary phase of a stellar collision.
>    The stellar collision ejected a cloud of hot debris into space. As the debris flew outward, it created a shock wave that, in turn, heated up hydrogen molecules in the debris cloud, producing the ultraviolet emissions scientists first observed back in 2004.
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> Scientists are trying to make sense of a physics-altering collision.
>    Roughly seven billion years ago, two monstrous black holes slammed together in a catastrophic celestial event so intense, it shot a pulse of gravitational waves out across the universe. Astonishingly, those gravitational waves only reached Earth one year ago, and astronomers now believe they've spotted the most powerful black hole collision yet: an event they've dubbed GW190521.
>    Researchers at the Laser Interferometer Gravitational-Wave Observatory (LIGO) in the U.S. and the Virgo Observatory in Italy first detected the waves—ripples in the fabric of space-time—in May 2019. The two smashed black holes at the heart of the collision were 66 and 85 times more massive than our sun, astronomers report in two papers published last week in Physical Review Letters and The Astrophysical Journal. When they collided, they formed a gargantuan black hole approximately 142 times more massive than our sun.
>    Not only is this likely the most powerful explosion ever recorded, but it proves the existence of a rare class of black holes: intermediate-mass black holes. “Now we can settle the case and say that intermediate-mass black holes exist,” LIGO astrophysicist Christopher Berry of Northwestern University, told National Geographic.
>    A black hole 85 times the mass of our sun theoretically shouldn't exist. It doesn't pair well with the theories researchers have about how stars die. Stars that range from a few times to 60 times the mass of our sun typically burn all of their fuel and eventually collapse in on themselves, forming a "conventional" black hole.
> Stars that are about 60 to 130 times more massive than our sun go out with a bang, but they usually don't become black holes. Instead, they form something called a pair-instability supernova. The heat that occurs during the star's compression is so powerful, all of the material ejected is destroyed. According to the current theory, it simply can't become a black hole. (Supermassive black holes, like the one photographed at the center of M87, form from stars millions to billions the mass of our sun.)