Jupiter, Eagle Nebula, and Bode's Galaxy

Observatory / Course Archives / ASTR 110 Fall 2019 / Jeong

Jupiter

By Jove, what cool clouds! Jupiter is the 5th and the largest planet in the Solar System. As a gas giant, it is made up of mostly hydrogen and helium, with no "true surface"; however, it is thought to have three 'cloud' layers, two of which are apparent in the image above. The swirling currents formed by warm emission from the inner layers of the planet create those holes and peaks, and the brighter parts are thought to be moist air and condensation. Isn't it cool to picture a planet made of clouds and wind? Galileo was the first spacecraft to penetrate into Jupiter's atmosphere, and it took the above image in near-infrared light.

Other interesting facts about Jupiter are that it has 79 confirmed and provisional moons to date, a faint ring made of dust particles, a strong magnetic field, and it has the iconic Great Red Spot, which is a massive storm which exists for centuries.The numerous 'spots' on Jupiter are long-lasting and incredibly fast wind storms moving the clouds like the above around. Imagine a windstorm twice as wide as Earth - that is the Great Red Spot!

Messier 16

The three 'Pillars of Creation' in the image above is a region in M16, the Eagle Nebula. This is a diffuse emission nebula approximately 5.5 million years old, spanning ~4-5 ly, and found at about 7000 ly from Earth, quite easily seen in the sky in the constellation Serpens. The beautiful array of colors in this nebula is a result of oxygen, sulfur, nitrogen, and hydrogen gases, as well as dust which are an ingredient for active star formation nearby. In fact, the nebula has several active sites of star formation, one of them being the 'Pillars of Creation.'

The actual eagle-like shape of the nebula was first discovered by a Swiss astronomer Philippe Loys De Cheseaux in 1745, and the 'Pillars of Creation' image by NASA was one of the 100 most influential images selected by the Time magazine in 1995. Most unfortunately, the famous Pillars of Creation pictured above may have disappeared by now, as a result of shock waves after the supernova that took place some 8000~9000 years ago. But we get to enjoy this beautiful view while it lasts a few thousand years more, so make sure not to miss it!

Messier 81

Bode's Galaxy is a bright, massive unbarred spiral galaxy found in the constellation Ursa Major, is at least about 13 billion years old and is at about 12 mly from Earth. Its massive size (radius~45 kly) and relatively close distance to the Earth allows for easy observation and imaging. It contains more than 250 billion stars and also a supermassive black hole (~70 million Msun) at its center. The black hole, in comparison with the one in the center of Milky Way, is 15 times as massive. Based on such findings, Hubble research theorized a proportionality between the mass of a galaxy's bulge and the size of its black hole in the nucleus.

The reader will notice that the galaxy has a yellowish center and bluish spiral arms; and this is an indication of older stars in the central bulge and young, hot stars in the spiral arms. There is also interstellar dust which fills the star formation regions in the spiral arms. The same pattern is seen with our own Milky Way Galaxy, which is comparable to M81 in size and age except that it is barred. The Milky Way galaxy belongs to the 'Local Group' (group of galaxies nearest to the Milky Way) and M81 belongs to the 'M81 Group' (group of galaxies at a distance of ~12mly from Earth), which just lies outside the borders of the Local Group. What would the fates of these neighboring look-alike galaxies be?