Thursday, November 24
Lunar Orbiter 2 took an extraordinary oblique photo of the crater Copernicus, 50 years ago (1966).
The 20.3-magnitude unnamed asteroid 106234 (2000 UJ44) may pass in front of the 9.0-magnitude star HD 217198 in Aquarius (δ=-10.9°; K0III; 386-417 ly) for up to 0.8 seconds around 6:48:39 p.m. ± 43s. Probability of seeing the event along the predicted centerline is 0.7%.
Thanksgiving Day
Friday, November 25
Jupiter is near the Moon this morning before dawn.
Lewis Morris Rutherfurd (1816-1892), American spectroscopist and celestial photographer, was born 200 years ago.
Algol (β Persei) reaches minimum brightness around 11:13 p.m. (mv = +3.4; usually +2.1).
Sunday, November 27
Alpha Monocerotid meteors may be seen around this date (3 meteors per hour, or less).
November Orionid meteors may be seen around this date (radiant rises at 6:30 p.m.; expected worldwide peak around 7 p.m.; radiant altitude 56° at midnight).
Monday, November 28
November Orionid meteors may be seen around this date (3 meteors per hour, or less; radiant transits the meridian at 1:34 a.m., altitude 63°; 34° as morning twilight begins).
The 15.5-magnitude Mars-crossing asteroid 2064 Thomsen may pass in front of the 13.3-magnitude star 4U 527-1438 in Pisces (δ=+15.4°; spectral type and distance unknown) for up to 38.2 seconds around 12:28:06 a.m. ± 13s. Probability of seeing the event along the predicted centerline is 92.6%. For more information, visit http://asteroidoccultation.com/asteroid.htm.
Winter begins in the northern hemisphere of Mars around 2 a.m.
Algol (β Persei) reaches minimum brightness around 8:02 p.m. (mv = +3.4; usually +2.1).
Tuesday, November 29
The Cassini Saturn orbiter will pass 6,800 miles above the surface of Titan at 6:30 a.m.
New Moon; rises 6:59 a.m.; transits 12:03 p.m.; sets 5:04 p.m.; δ = -17° in Ophiuchus; 4.5° from the Sun (center-to-center) at 5:43 a.m. (below horizon).
The Sun enters the constellation Ophiuchus at 10:02 a.m.
Venus is exactly 1.00 AU from the Earth at 12:22 p.m.
The International Space Station will cross the sky from 6:33:16 to 6:34:49 p.m. (SSW). Peak magnitude: -1.4; Highest altitude: 23°. Closest distance: 568 miles. 6:34:49 p.m. disappears into the shadow of the Earth between Fomalhaut (Piscis Austrinus) and Mars (Capricornus).
Wednesday, November 30
Eric Elst (1936-), Belgian astronomer who has been a prolific discoverer of asteroids, celebrates his 80th birthday today.
Ernst Chladni (1756-1827), German physicist and musician who was a pioneer in the study of meteorites, was born 260 years ago.
The International Space Station will cross the sky from 5:42:02 to 5:45:19 p.m. (S to ESE). Peak magnitude: -1.7; Highest altitude: 21°. Closest distance: 605 miles. Astronomical twilight. 5:43:03 p.m. near Fomalhaut; 5:44:15 Deneb Kaitos (β Ceti); 5:45:19 disappears into the shadow of the Earth to the right of the Head of Cetus.
The Iridium 94 satellite ("Plutonium") will sunglint to -3.3 magnitude around 5:52:09 p.m. at azimuth 40° (NE) and altitude 54° (587 miles), just below Cassiopeia, during astronomical twilight.
Jupiter is exactly 6.00 AU from the earth at 6:38 p.m. (below horizon).
Thursday, December 1
December Monocerotid meteors may be seen around this date (2 meteors per hour, or less).
The Progress MS-4 robotic cargo ship is scheduled to launch from the Baikonur Cosmodrome in Kazakhstan at 8:51 a.m., on a mission to the International Space Station.
The Moon reaches its most southerly declination this month (-19° 42' 50.02") at 1:42 p.m. in Sagittarius.
"Do High Equivalent Width LAEs Exist in the Local Universe? Insights from a Flux-Limited GALEX LAE sample at z~0.3" by Isak Wold, Postdoctoral Fellow, Department of Astronomy, University of Texas, Austin; 4421 Sterling Hall, UW-Madison, 2:30 - 4:00 p.m.
The north geomagnetic pole is moving away from us. And the northern hemisphere's auroral oval is centered on the north geomagnetic pole. The auroral oval is always present and typically has a radius of 900 to 1600 miles, and a latitudinal width of 300 miles or so, but both the radius and width are considerably larger during a major auroral event. The auroral oval is usually widest around the midnight longitude of the Earth.
Presently, the north geomagnetic pole is located about 2626 miles from Dodgeville in a direction of 4.7° east of north. Here is how the distance to the north geomagnetic pole is changing with time.
1981 - 2538 miles1986 - 2548 miles
1991 - 2557 miles
1996 - 2568 miles
2001 - 2581 miles
2006 - 2593 miles
2011 - 2609 miles
2016 - 2626 miles
Does this mean that we will see fewer auroras in the future? If the trend continues, yes, but aurora lovers should cheer up as it will be several decades before there will be a significant decline in auroral activity in SW Wisconsin.
And, if the Earth's magnetic field continues to weaken, we might actually see more aurora! Right now, the Earth's total magnetic field strength at Dodgeville is 54,368 nT (nT = nanotesla). That's a decline of 6.4% since 1981.
As the dipole magnetic field (i.e. the north and south geomagnetic poles) strength decreases, secondary terms in Earth's complex magnetic field (quadrupole, octupole, etc.) begin to play a more important role, and this could eventually lead to auroral activity favoring certain low and mid-latitude longitudes.
On page 45 of the November 2016 issue of Sky & Telescope, Fred Schaaf writes, "Were it not for the S&T alert about the imminent arrival of 'Bright Comet Bennett' in early 1970, I may well have missed what I still regard as the most beautiful comet I've ever seen." Schaaf was 15 at the time, I was 13, and the comet he refers to is Comet Bennett (C/1969 Y1). This was my first (and best) comet, too. I was living in Sioux City, Iowa at the time, and my parents had gotten me my first telescope—a Sears 90 mm reflecting telescope with a cardboard tube, U-channel metal tripod legs, and a ball-and-socket movement, as I recall. I received that telescope at Christmas in 1969, and heard about the comet (I don't remember where) in late March 1970, so got up early one cold, crisp morning and hauled my lightweight telescope out to my backyard at 3024 Nebraska St. (light pollution wasn't nearly so bad in those days) and found the comet! I was mesmerized by the view (both to the naked-eye and telescopically). Fred includes a black-and-white photo taken by Dennis di Cicco with his article, and that is exactly how I remember seeing the comet! Here is that same photo showing more detail than on the printed page.
Albert Einstein's Special Relativity gives us a way to time travel, but only to our future. If you traveled close enough to the speed of light, you could return to Earth's future since you would have aged at a slower rate relative to the Earth.
Traveling to the past is verboten, however, due to the inherent paradoxes. The classic example is if you could travel into the past and somehow keep your parents from ever meeting, how could you exist? The many-worlds interpretation of quantum mechanics resolves this kind of paradox, but at the expense of accepting as fact something that is completely speculative (not to mention, unnerving).
But what if a very advanced civilization a few light years distant had pointed a very large telescope (with adaptive optics, presumably) at the Earth and recorded our past for later broadcast back to Earth?
The best spy satellites currently have a resolution around 10 cm. To get that kind of resolution at interstellar distances, you would need a telescope lens or mirror 0.424 AU in diameter for every light year of distance between ET and Earth. That would be a telescope about the size of the orbit of Mercury at just 2 light years distance, and the nearest star beyond our solar system is 4.2 light years away! There, too, would be the formidable problem of glare from the Sun to solve.
If ET had a telescope the size of the orbit of Neptune, an Earth-resolution of 10 cm could be achieved out to a distance of 143 light years.
In this way, we could view (but not touch) our past.
Of course, any sentient beings located much further away—say thousands, millions, or billions of light years distant—would right now be receiving light from Earth that left here that long ago—our past is their present. But a ridiculously large telescope would be needed to garner the requisite resolution, and it would take the same amount of time (approximately) to get those images back to us...
