TSTW 1/26/12
Thursday, January 26
Ranger 3, the first U.S. spacecraft attempt to impact the Moon, was launched 50 years ago (1962). It missed.
The Moon crosses the celestial equator heading north at 3:50 p.m.
The 12.7-magnitude asteroid 179 Klytaemnestra may pass in front of the 12.8-magnitude star 2UCAC 35022054 in Cancer for up to 4.5 seconds around 10:36:39 p.m. Visit http://asteroidoccultation.com/asteroid.htm for more info.
Friday, January 27
Newly-discovered asteroid 2012 BX34 passes just 36,684 miles (0.16 LD) above the South Pacific at 9:24 a.m.
The Progress M-14M (46P) robotic cargo ship is scheduled to dock with the International Space Station at 6:08 p.m.
Uranus crosses the celestial equator heading north at 9:41 p.m. It will remain north of the celestial equator until the year 2052.
The Great Red Spot crosses Jupiter's central meridian around 10:12 p.m.
Saturday, January 28
Johannes Hevelius (1611-1687), Polish astronomer who authored the first books about comets, Prodromus cometicus (1665) and Cometographia (1668), died 325 years ago.
Io reappears from Jupiter's shadow around 9:46 p.m.
Sunday, January 29
The 16.6-magnitude asteroid 2146 Stentor may pass in front of the 10.2-magnitude star Tycho 0166-01004-1 in Monoceros for up to 1.9 seconds around 3:12:31 a.m.
Jupiter is near the Moon this evening.
The Cassini Saturn orbiter will make a distant flyby of Titan (19,343 miles) at 11:40 p.m.
Monday, January 30
The 16.3-magnitude unnamed asteroid 15436 (1998 VU30) may pass in front of the 11.3-magnitude star Tycho 0741-00541-1 in Gemini for up to 6.2 seconds around 4:10:24 a.m. Visit http://asteroidoccultation.com/asteroid.htm for more info.
The Great Red Spot crosses Jupiter's central meridian around 7:43 p.m.
The Iridium 35 satellite will sunglint to -5 magnitude around 8:07:31 p.m. at azimuth 32° (NNE) and altitude 42°, in Camelopardalis.
Hubble Space Telescope (W to SSW) - 8:16:05 p.m. right of Venus; 8:16:40 Circlet of Pisces; 8:18:43 left of Jupiter; 8:19:00 Head of Cetus; 8:19:16 disappears into the shadow of the Earth in Taurus; 0.9m, 68°.
First Quarter Moon, 10:10 p.m.; rises 11:47 a.m.; transits 6:38 p.m.; sets 1:34 a.m. Tuesday; δ = +17°.
Tuesday, January 31
Asteroid 433 Eros is closer to us (16.6 million miles) than it has been since 1975, and it won't be this close again until 2056, 2:58 a.m. At this time it is in the constellation Sextans, high above the horizon.
Alvan Graham Clark (1832-1897) discovered Sirius B (a white dwarf), the companion to Sirius A predicted by Friedrich Bessel (1784-1846) in 1844, 150 years ago (1862).
Can you spot 4.3-magnitude Botein (Delta Arietis) near the bright limb of the Moon soon after 7:52 p.m. using binoculars or a telescope?
Wednesday, February 1
The Moon is near the Pleiades this evening. Use binoculars.
The Great Red Spot crosses Jupiter's central meridian around 9:22 p.m.
In Antarctica, beneath two-and-a-half miles of ice, lies a 160 x 30 mile body of water called Lake Vostok that has not seen the light of day for perhaps 15 to 25 million years. And this lake is deep: 1,129 feet on average but in places up to 3,300 feet deep. At the bottom of the lake lies 230 feet of sediment. What secrets lie within this lake? Is there life there? Scientists want to know, but they don't want to do anything that would contaminate the lake with materials or organisms from above. So, for now, the lake remains wholly unexplored—except remotely via radar, magnetic, and seismic means. However, a Russian research team has already drilled to within 900 ft. of the surface of the lake, and they plan to launch an underwater robot to explore Lake Vostok as early as late this year. These explorations are not without controversy, however. There is deep concern within the scientific community that Lake Vostok should not be breached until there is zero risk of contamination.
Lake Vostok could be explored by a cryobot carrying a hydrobot. A cryobot is a robotic probe that melts its way down through a substantial amount of ice, and while it does so, collects data and images and transmits them to the surface above. When the cryobot reaches the liquid environment beneath the ice, it would deploy a hydrobot. The hydrobot is a self-propelled robotic probe made to operate in a liquid environment (think submarine), and it, too, would collect images and data and transmit them to the surface above. Building a cryobot and a hydrobot, while challenging, is not nearly so difficult as making absolutely sure that they do not bring any contaminants with them into a pristine environment.
As it turns out, successfully (and safely) probing Lake Vostok will be an excellent test run for the cryobots/hydrobots that will eventually be sent to Europa and Enceladus. Europa, the smallest of the Galilean satellites of Jupiter and only slightly smaller than our own Moon, is thought to harbor a liquid ocean beneath a very cold (by terrestrial standards) icy crust that is between 6 and 19 miles thick. But scientists have the same concerns about Europa as they do about Lake Vostok: contaminating any pristine environment where life possibly already exists is out of the question.
Scientists are so concerned about terrestrial contamination of Europa that the aged Galileo spacecraft, after nearly running out of steering fuel, was intentionally deorbited through the atmosphere of Jupiter rather than risking an eventual crash into Europa. Galileo's crushing demise on September 21, 2003 ensured that Europa would remain contaminant free—for now.
Enceladus, the sixth largest moon of Saturn and only one-sixth the size of Europa, may also harbor a liquid ocean some 25 miles beneath its icy surface. It is thus another prime candidate for a cryobot/hydrobot mission.
A century-and-a-half ago this week, renowned telescope maker Alvan Graham Clark was testing out a new 18.5-inch lens (destined for the University of Mississippi but ending up at the Dearborn Observatory in Evanston, Illinois) in a makeshift telescope tube, and in pointing it at Sirius, the brightest star in the night sky, he discovered that Sirius was accompanied by a faint nearby companion star.
Sirius B, as it came to be called, is hotter than Sirius A and yet it is some 9,000 times fainter. The only way for a star to be that hot and appear so faint compared to its companion is for it to be very small. Here we have, just 8.6 light years away, a star that is smaller than the Earth but that contains as much mass as the Sun! Such a star is called a white dwarf. A teaspoon of this star would weigh five tons.
Sirius A and Sirius B orbit each other every 50.1 years in a highly elliptical orbit (e = 0.59). Sirius A is so much brighter than Sirius B that it is difficult to see Sirius B against the glare of the brighter star. We'll have our best opportunity to see Sirius B through the telescope in 2022, when the two stars are farthest apart (11 arcseconds).
