In recent nights, a bright, attention-grabbing light has been observed low in the eastern sky around 19:30 local daylight time. It shines with a steady silver glow, and after a couple of hours, when it has risen noticeably higher in the east-southeast sky, it seems to attract attention.
Of course, that would make some sense because you’re looking at an object named after the king of the gods as well as the king of the planets: Mighty Jupiter.
And it’s a pretty auspicious week, because we’ll see Jupiter appears as large and bright as it can be from our vantage point on Earth because it is approaching perihelion: the point in its 12-year orbit that places it closest to The sun.
On the topic: NASA says Jupiter is closest to Earth in 59 years
Jupiter now appears 11% larger and more than one and a half times brighter than it was in April 2017, when it was near aphelion (the point in its orbit furthest from the Sun). Even 7-stop binoculars held steady will show Jupiter as a tiny disc. A small telescope will perform much better, while in larger instruments Jupiter resolves into a series of reds, yellows, browns, and browns, along with a host of other telescopic details. Amateur astronomers have been photographing this great planet all summer as it approaches Earth. The opposition, when it will be in the sky all night, from sunset to sunrise, takes place on Monday (September 26).
At 10 p.m. ET on Sunday (September 25), Jupiter will make its closest approach to Earth since 1963. Then it will be at a distance of 367,413,405 miles (591,168,168 km). It may not seem quite “close,” but Jupiter is so large and bright that not only is it easily visible to the naked eye, but through a small telescope with only 36 degrees of magnification, it appears as large as the Moon to the naked eye. .
A giant among giants
Jupiter’s diameter is nearly eleven times that of Earth at a width of 88,846 miles (142,984 km). It takes almost 12 years to make one trip around the sun. But if Jupiter’s year is long, the day is short. The big planet rotates once in less than 10 hours. For a planet of this size, this rotation rate is amazing. A point on Jupiter’s equator moves at 22,000 miles per hour compared to 1,000 miles per hour for a point on Earth’s equator. This rapid rotation rate gives Jupiter the appearance of a slightly flattened ball. It has a rocky core surrounded by a thick mantle of metallic hydrogen, enveloped by a massive atmospheric mantle of colorful clouds of ammonium hydrosulfide.
Jupiter is an enormous giant planet, with a mass more than twice that of all seven other planets combined. It has one of the most mysterious spots on the face of the planet: A big red spot which comes and goes unpredictably, and is as vast as the Earth. There is also some evidence that Jupiter loses more heat energy through radiation than it receives from the Sun, and so it can produce its own energy – an activity usually more typical of a star than a planet.
And like Earth, Jupiter has a magnetic field; a huge belt of electrically charged particles in the shape of a donut that surrounds the planet – a ring similar to Van Allen belts of charged solar particles that are in captivity Earth’s magnetic field.
Dance of the months
Let’s not forget Four large moons of Jupiter, which were discovered 412 years ago by Galileo. They are a telescopic treasure. The four are Io, Europa, Ganymede and Callista — jovially race each other and orbit Jupiter so quickly (1.68 days for Io to 16.7 days for Callisto) that they change their appearance from hour to hour and night to night, casting their shadows on the planet, disappearing behind her giant. disk, or falling into its shadow.
For example, on Sunday (September 25), you will be able to see three moons on one side of Jupiter (Io, Europa and Callisto), and a fourth moon (Ganymede) all by itself on the other side. On Monday (September 26), Ganymede will be joined by Europa and Io; now it’s Callisto, who will be all by herself on the other side of Jupiter. Finally, on Tuesday (September 27) you will see two moons on one side (Europa and Ganymede) and two (Io and Callisto) on the other.
In fact, at 12:08 a.m. EDT on Wednesday (Sept. 28) (27:08 PST on the 27th), Ganymede appears to be crossing Jupiter in what is called a transit. In addition to the “big four”, Jupiter has 76 more moons. Many of them are exceptionally small and were discovered by space probes that flew by Jupiter in the 1970s, 80s and 90s.
Does Jupiter rotate?
When Jupiter appears high in the sky, it may appear to some to be moving in a circle or spiral. Over the years I have received emails from people who claim to have seen Jupiter doing just that: moving back and forth.
So why does it look like it’s moving? It is likely that those who saw this strange movement experienced an autokinetic effect. It is a phenomenon of human visual perception in which a stationary small point of light in an otherwise dark or featureless environment appears to move. Many UFO sightings are also attributed to the autokinetic effect stars or planets. Psychologists attribute the perception of motion where there is none to “small involuntary movements of the eyeball.” The autokinetic effect can also be enhanced by the power of suggestion: if one person reports that the light is moving, others are more likely to report the same.
Jupiter is currently shining in the constellation Pisces, a stellar sample consisting mostly of faint stars. Under a clear, dark sky with no moon nearby, Jupiter will shine with little or no competition from other nearby stars. If a person gazes at Jupiter continuously for perhaps 15 to 30 seconds, it is possible that an autokinetic effect will kick in and cause Jupiter to rotate or perhaps describe a small circle.
Try staring at Jupiter this week in the late evening hours and see if it moves for you.
If you want to see a great view of Jupiter in opposition, don’t miss our guides on the best binoculars and the best telescopes to spot Jupiter or other objects in the night sky. For the best photos of Jupiter, check out our tips cameras for astrophotography and best lenses for astrophotography.
Editor’s note: If you’ve taken a photo of Jupiter and would like to share it with Space.com readers, send your photo, comments, name and location to firstname.lastname@example.org.
Joe Rao works as an instructor and visiting lecturer in New York Hayden Planetarium (opens in a new tab). He writes about astronomy for Journal of Natural History (opens in a new tab), Bakery almanac (opens in a new tab) and other publications. Follow us on Twitter @Spacedotcom (opens in a new tab) and so on Facebook (opens in a new tab).
https://www.space.com/jupiter-at-its-best-opposition-sept-2022/ See Jupiter at its best in opposition, closest to Earth since 1963