Saturday: If the Sun looks big today, your eyes are not playing tricks on you. The Earth is at perihelion at 7:30 this morning. If you dig out your Greek language textbook, you’ll see that peri- means “in close proximity” and helios means “Sun”. So, perihelion is when an object is closest to the Sun in its orbit, about 1.5 million miles closer than its average distance of 93 million miles. Since it is winter in the Northern Hemisphere now, the seasonal temperature changes must not be caused by the Earth getting farther from and closer to the Sun. Otherwise, we’d have summer when the Earth is closest to the Sun. The seasons are caused by the angle of the sunlight hitting the Earth. In the winter, sunlight hits the Earth at a very low angle, an angle far from perpendicular or straight up and down. This means that a given “bundle” of sunlight is spread out over a large area and does not warm the surface as much as the same bundle in the summer. For the Northern Hemisphere, that very low angle occurs in December, January, and February.
Sunday: Has it been tough to wake up this past week? It
should have been because the sunrise has been getting a little later since
summer started. I know. I know. December 21 was the shortest day of the year.
But, because the Earth’s orbit around the Sun is elliptical and not circular,
the Earth does not travel at a constant speed. It moves faster when it is
closer to the Sun and slower when it is farther away. This leads to the latest
sunrise occurring in late December/early January and the earliest sunset
occurring in early December. Neither of these happen on the first day of
winter. On the first day of winter, however, the interval between sunrise and
sunset is the shortest, making it the shortest day of the year. For more
information, go to http://goo.gl/SJC5r.
Monday: At 8:30 p.m., Jupiter is six fists above due
southeast and Mars is three fists above due east.
Tuesday: Let’s review three important sets of three cats.
There’s Josie, Valerie, and Melody of Josie and the Pussycats. Felix, Tom, and
Sylvester from old time cartoons. And, if you want to get away from the
mind-numbing effects of television, there’s Leo the lion, Leo Minor, and Lynx
in the night sky. Leo is by far the most prominent of these three
constellations. Its brightest star called Regulus is two fists above the
eastern horizon at 10:00 p.m. The backwards question mark-shaped head of Leo is
above Regulus and the trapezoid-shaped body is to the left of it. Leo Minor
consists of a few dim stars right above Leo. Pretty wimpy. The long dim
constellation called Lynx spans from just above Leo Minor to close to straight
overhead. You and fellow stargazers won’t need to wear a long tail or ears to
enjoy these stellar cats.
Wednesday: In 1984, American singer Rockwell released the
song “Somebody’s Watching Me”, backed up by Michael Jackson. In 2020, NASA’s
Spitzer Space Telescope released a picture of two bubbles of gas and dust that
look like eyes watching you. Stare back at them by going to https://www.spitzer.caltech.edu/image/ssc2020-17a-something-out-there-is-watching-you.
Thursday: Tonight, Venus is as far away from the Sun in the
sky as it will get this orbital cycle. Since Venus is in the evening sky, it is
east of the Sun so this occurrence is called the greatest eastern elongation.
This evening will be the best evening to observe Venus for the next few weeks.
Venus is two fists above the southwestern horizon at 6:30 p.m. Saturn is a fist
to the upper left of Venus tonight. By mid-April, Venus will be visible in the
morning sky.
