The Crestone Eagle • October, 2021
Skies Over Crestone: October 2021
by Kim Malville
Jupiter is the third-brightest natural object in the Earth’s night sky after the Moon and Venus. It is the bright object in the southern evening skies. Saturn is the fainter planet to the right of Jupiter.
October 9-10: Enjoy the one of the two best conjunctions of the month as the slender crescent moon passes close to Venus in the evening skies about 45 minutes after sunset. Venus is the brightest planet with a magnitude of -4.3 (a negative magnitude is bright; the magnitude of the sun is -26.7!). Be quick! A half hour after sunset Venus will be only 12° above the southwest horizon
October 14: The waxing gibbous moon lies between Jupiter and Saturn.
October 15-16: Another lovely conjunction occurs when brilliantly white Venus comes within 1.5° of ruddy Antares soon after sunset above the southwestern horizon. The contrast in colors will be stunning. But they will set soon, so be quick and nimble. This kind of close encounter of Venus and Antares doesn’t happen very often. The next such conjunction will not occur until October 2029.
Jupiter the giant
Jupiter is the fifth planet from the Sun and the giant of our Solar System. It is almost a second sun in our vicinity, with a mass more than two and a half times that of all the other planets in the Solar System combined.
Jupiter is primarily composed of hydrogen, but helium constitutes one quarter of its mass and one tenth of its volume. It likely has a rocky core but lacks a well-defined solid surface. We see only its cloud tops. The on-going contraction of its interior generates heat greater than the amount received from the Sun. Because of its rapid rotation Jupiter possesses a strong magnetic field otherwise known as a magnetosphere, like ours, often known as the Van Allen belts.
We have a magnetic tail, blown outward by the solar wind, reaching our moon, 240,000 miles away. Jupiter’s magnetic tail is huge, nearly 500 million miles long, covering the entire distance to Saturn’s orbit. Jupiter has 80 known moons and possibly many more. Four of these are the large Galilean moons discovered by Galileo Galilei in 1610. The closest moon, Io, is the most volcanically active object in the solar system. The largest, Ganymede, has a diameter greater than that of the planet Mercury.
Jupiter is most likely the oldest planet in the Solar System. Current models of Solar System formation suggest that Jupiter formed at a distance from the early Sun where the temperature is sufficiently cold for volatiles such as water to condense into solids. It first assembled a large solid core before accumulating its gaseous atmosphere.
The strangest supernova yet
For the first time, astronomers have captured evidence of a rare double cosmic cannibalism—a star swallows its sibling, which had turned into a black hole. Almost like a Greek revenge myth, that sibling eats it way down to the star’s core and eats part of its heart, causes the star to explode. The result is a single a black hole, the remnant of the original two brothers, now joined together forever in an eternal dark embrace.
The first hints of the gruesome event came from the Very Large Array, a collection of 27 enormous dishes in the New Mexican desert near Socorro. During the observatory’s scans of the night sky in 2017, a burst of radio energy was seen as bright as the brightest exploding supernova as seen from Earth in a galaxy approximately 480 million light-years away.
Dillon Dong, a graduate student in astronomy at Caltech, and his colleagues made follow-up observations of the galaxy using the VLA and one of the telescopes at the W.M. Keck Observatory in Hawaii. The Keck telescope caught a luminous outflow of material spewing in all directions at 2 million miles per hour from a central location, suggesting that an energetic explosion had occurred there in the past.
Piecing the data together, Dong and his colleagues think this is what happened, which they described in an article in Science in its September 3 issue.
Most massive stars, more massive than eight times the mass of the sun, are born in close binaries, that is, as double stars. In some systems, the faster-evolving (more massive) star runs out of fuel in its core and is no longer able to support the weight of its outer layers. The star implodes, creating an immensely hot explosion which explodes outward as a supernova. These supernovae are true cosmic spectaculars, challenging the brightness of the entire galaxy in which they live. But there is more: the result is a compact object (neutron star or black hole) produced by the pressure of the explosion. It continues in a close orbit with its companion and slowly spirals inward toward its companion, creating more havoc, falling into the large star. If it is a black hole, it will work its way downward into the core, gobbling up matter as it falls inward.
Just consider what happens then. The matter simply disappears down the throat of the black hole, never to be seen again. The hot gas that once supported the star is gone; its foundation has vanished. The star cannot hold together and collapses. So much material falling inward bounces and creates a new exploding supernova, hurtling material outward nearly at the speed of light, which seeds the surrounding space with new elements. Eventually some of that matter may condense into new stars, new planets, and perhaps new life. Life goes on.