Saturday: Jupiter is two fists held upright and at arm’s length above due east and Saturn is about three fists above the south-southeastern horizon at 11:00 p.m. Jupiter is the much brighter of the two. When you are looking at this part of the sky, you are looking in the direction of more than just the two planets. You are also looking in the direction of their moons. Titan, Saturn’s largest moon, is easily visible with a small telescope, about one and a half “ring diameters” to the side of Saturn at this time. Three of Jupiter’s four largest moons are also visible with a small telescope. Callisto, Io, and Ganymede are on one side of Jupiter, with Callisto appearing the closest and Ganymede the farthest away. Europa is lost in the glare of Jupiter. Recently, astronomers discovered that Callisto’s atmosphere has 1,000 times more molecular oxygen than current models can explain. For more on this, go to https://www.cnet.com/science/space/jupiters-moon-callisto-has-a-whole-lot-of-oxygen-scientists-struggle-to-explain/.
Sunday: Three years ago, astronomers announced that they
detected phosphine, a possible biosignature of life, in the upper atmosphere of
Venus. Although the surface of Venus is inhospitable, astronomers have long
speculated that the upper atmosphere could harbor life. Not Cloud City life
from The Empire Strikes Back but maybe microbial life. Last year, astronomers
concluded that the original scientists found the signature of sulfur dioxide,
not life. Last year, the private company Rocket Lab published details about the
first privately funded mission to another planet - their trip to Venus, The
trip was originally scheduled to launch this year but has been delayed to at
least 2025. This Venus storyline is an excellent example of science at work. In
less than two years, science went from “we may have found a marker for life on
Venus” to “it is unclear if we found a marker for life” to “we probably didn’t
find a marker for life” to “let’s visit Venus to closely study the thing we
thought was a marker for life”. Do an internet search of the words venus and
phosphine and read the articles to follow the story. To get yourself in the
mood, go outside at 6:00 a.m. Venus is two and a half fists above the eastern
horizon at this time. It is the brightest it will be all year. Read more about
the potential mission at https://www.space.com/rocket-lab-private-venus-mission-delayed-2025.
Monday: The bright star Vega is about five fists above the
western horizon at 11:00 p.m. Its fellow Summer Triangle star Deneb is about
two fists above it. Altair, the third star in the triangle, is about four fists
above due southwest.
Tuesday: The bright star Capella is two fists above due
northeast at 11:00 p.m.
Wednesday: The Beehive Cluster is less than a half a fist to
the lower right of the waning crescent Moon at 5:00 a.m. They are about three
fists above due east.
Thursday: The bright star Sirius is two fists above the
south-southeastern horizon at 6:00 a.m.
Friday: At 10:50 p.m. PDT, the center of the Sun crosses the
celestial equator and passes into the southern sky. The celestial equator is an
imaginary line that divides the sky into a northern and southern half. When the
Sun is in the southern half of the sky, it appears to take a shorter path from
rising to setting. It also does not get as high in the sky at noon. This leads
to shorter days and longer nights. Since the Sun crosses the celestial equator
today, there is an instant when it is equally in the northern and southern sky,
called the north and south celestial hemispheres. This so-called “equal night”
is given by the Latin word equinox. Thus, today is known as the Autumnal
Equinox. However, the day and night are not of equal duration today. The sun
rises at 6:49 a.m. and sets at 6:59 p.m. in the northern latitudes of the
United States. At these latitudes, day and night are closest to equal duration
on Monday.
The positional information in this column about stars and
planets is typically accurate for the entire week. For up to date information
about the night sky, go to https://nightsky.jpl.nasa.gov/planner.cfm.
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