2022, June 29:  Last Call, Mercury, Night Sky, Black Hole

Astronomy, Sky Watching
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June 29, 2022:  Four bright planets remain in the morning sky before daybreak.  Around midnight, the black hole at the galaxy’s center is low in the south.

Chart Caption – 2022, June 29: The four bright planets are along an arc during morning twilight.

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by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 5:19 a.m. CDT; Sunset, 8:30 p.m. CDT.  Check local sources for sunrise and sunset times for your location.

The moon reached the New moon phase overnight.  Find a thin crescent low in the west-northwest tomorrow evening after sundown.

Morning Sky

SUMMARY OF PLANETS IN 2022 MORNING SKY

Mercury’s last call is this morning.  The planet is retreating into brighter twilight and becoming more difficult to see with the other four morning planets.

Start looking at least an hour before daybreak to see the four bright planets – Venus, Mars, Jupiter, and Saturn – along an imaginary arc from the east-northeast horizon to about one third of the way up in the south.

To find Venus, locate a clear horizon, low in the east-northeast.  A hilltop or elevated structure should provide a look over local obstructions. 

Bright Jupiter is nearly 40° up in the southeast.  Dimmer Mars is 18.5° to the lower left of the Jovian Giant.  The Red Planet is about one-third of the way from Jupiter to Venus.  Lone Saturn, slightly dimmer than Mars, is about 30° above the southern horizon.

To find Mars and Saturn as the sky brightens during the next several minutes, reference their places in the sky compared to a tree branch or roof top.  They will be easier to find later when Mercury is visible by using the terrestrial landmarks.  Venus and Jupiter are relatively easy to find, when Mercury becomes visible.

Chart Caption – 2022, June 29: At 45 minutes before sunrise, Mercury is low in the east-northeast, to the lower left of Venus.

At forty-five minutes before sunrise, Mercury is about 4° above the east-northeast horizon, 11.7° to the lower left of Venus.  It’s only about 4° above the horizon and 10.1° to the lower left of Aldebaran that is making its first morning appearance.  Use a binocular to find Mercury and the star.  Then look for the other four planets using the reference points for Mars and Saturn.

We say “goodbye” to Mercury in this rare parade of bright planets that are visible in order from the sun until 2100.  Mercury passes its superior conjunction on July 16.  It swings into the evening sky for a very unfavorable appearance in the western sky.

Night Sky

Chart Caption – 2022, June 29: Sagittarius A star, the Milky Way’s suspected black hole, is in the south during the midnight hour.

The center of the galaxy is visible low in the south around midnight.  A suspected black hole – a very massive object with gravity so strong that light cannot escape – has been suspected to supply the gravity to hold the Milky Way galaxy together.  This one is thought to contain the matter of four million suns.

Photo Caption – An image like this shows that our galaxy is always “partly cloudy.” Not unlike Earthly clouds that block parts of the sky (say on a starry night), tremendous clouds of gas and dust obscure the things that are beyond them. (Credit: Kit Peak National Observatory)

The black hole is hiding behind the stars, nebulae, and dust clouds in the region.  We cannot see through the foreground celestial wonders with conventional optical telescopes, in the same way we cannot see through clouds in the atmosphere.  There’s just too much stuff in the way.

Photo Caption – This image shows the star-studded center of the Milky Way towards the constellation of Sagittarius. The crowded center of our galaxy contains numerous complex and mysterious objects that are usually hidden at optical wavelengths by clouds of dust — but many are visible here in these infrared observations from the Hubble Space Telescope. (Photo Credit: ESA, NASA)

The center of the galaxy is behind the stars of Sagittarius.  The main part of the constellation resembles a teapot and has that moniker.  The black hole is between the Teapot and the main stars of Scorpius, with its bright star Antares.

The Milky Way’s black hole has been long suspected because of observations that see stars moving very quickly in that region of space, some 27,000 light years away. This black hole has the name Sgr A* (“Sadge-ay-star”); the letters Sgr are the abbreviation for Sagittarius.

Photo Caption – The main panel of this graphic contains X-ray data from Chandra (blue) depicting hot gas that was blown away from massive stars near the black hole. Two images of infrared light at different wavelengths from NASA’s Hubble Space Telescope show stars (orange) and cool gas (purple). These images are seven light years across at the distance of Sgr A*. A pull-out shows the new EHT image, which is only about 1.8 x 10-5 light years across (0.000018 light years, or about 10 light minutes). (Credit: NASA (EHT Collaboration))

Recently, the Event Horizon Telescope (EHT) team released a colorized radio map of the suspected black hole.  Radio waves and other forms of energy pass through the haze of the intervening stars and dusty debris to reach our solar system.

Photo Caption – A 25-meter (82 feet) radio telescope at the Very Large Array in Socorro, New Mexico.

Radio telescopes are much larger than optical telescopes, but they cannot see the same details that can be seen on celestial objects like that of the neighborhood sky watcher’s backyard scope.  To see the sky in considerable detail, radio telescopes are connected across the globe to reveal the detail of a single radio telescope that is the size of Earth. In this case, EHT combined the data from eight radio telescopes from across the globe, as the individual radio telescopes collected radio waves for many hours.

The EHT press release states that the group of 300 researchers worked for five years to overcome technical issues and to analyze the data with super computers.

The image shows a dark center with a yellow-orange ring around it.  The dark center is the black hole with a disk of hot debris around it.  The brighter spots indicate regions that release more energy and could be interpreted as hotter regions on the disk.

This radio image along with an earlier one made of one on the galaxy Messier 87 look similar, although M87’s black hole is more massive.

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