Bakersfield College

Bakersfield Night Sky -- June 18, 2016

Bakersfield Night Sky – June 18, 2016
By Nick Strobel

Just two days until the June solstice when the sun will be at its northern most position on the sky. This is the official start of summer and since it depends on the position of the sun with respect to the stars on our sky, I can tell you that summer will officially start at 3:34 pm Pacific Time on June 20th. The sun's energy will hit our part of the earth most directly, so the cooking power will be greatest on that day. Also, the sun is above the horizon for the longest amount of time, so the cooking time will be longest on that day.

However, like a cake baking in the oven, it takes a while for everything to warm up, so our hottest days (and nights) are still to come this summer. With temperatures already reaching over 100 degrees F earlier in June, I'm not looking forward to July and August! For this year's solstice, the moon will mark the occasion with a full phase

The evening sky has the three outermost planets visible to the naked eye, Jupiter, Mars, and Saturn, within 90 degrees of each other. Jupiter is the super-bright star in the southwest sky below the stars of Leo. Mars is already up in the southeast among the dim stars of Libra at sunset. Saturn is rising at sunset and is in between Scorpius and Ophiuchus. Right next to Saturn tonight is the waxing gibbous moon. See the star chart below.

In advance of the Juno spacecraft's orbit insertion around Jupiter on July 4th, a team of astronomers released results last week of their observations of Jupiter in the radio band using the Very Large Array. The radio observations enabled them to peer into Jupiter down to depths of about 100 kilometers below the cloud layers. Although many of the features visible in the radio band match up with features we see in ordinary visible light, some features look like rising plumes of hotter gas from greater depths. The deeper you go into Jupiter, the hotter it gets.

The Juno spacecraft will be able to peer down to depths of about 600 kilometers below the cloud tops with its microwave radiometer. At that depth the pressure is equivalent to 1000 earth atmospheres. Six different microwave bands will investigate the atmosphere structure, composition, and motions at six different depths down to the 600 kilometer mark. The super-precise measurements of Juno's speed (about 1 part in a billion) will enable us to map the lumpiness of Jupiter's gravity field and that will enable us to determine Jupiter's structure down to its core.

One direct way the general public can be involved with the Juno mission is the JunoCam. With JunoCam, you can vote on the best locations in Jupiter's atmosphere for JunoCam to image. Once the images are taken, the JunoCam team will post the raw images for people to download and process with their own software. Then people will be able to reupload the processed images to the JunoCam for the rest of the world to enjoy. See www.missionjuno.swri.edu/junocam for more about JunoCam.

On the other end of the distance scale, a team of astronomers with the National Optical Astronomy Observatory (headquartered in Tucson, AZ across the street from my undergraduate alma mater) found an extremely large protocluster of galaxies that is so far away we're seeing it as it was 12 billion years ago. There are nearly 800 galaxies in the protocluster with the very catchy name of PC217.96+32.3. It looks like the protocluster will become two clusters, one with a mass of a quadrillion suns and the other more than 600 trillion suns.

The protocluster is one of the most massive structures known at the time in the universe's history. Although, there are plenty of galaxy clusters in the present-day universe, we're not sure of how they formed. Supercomputer simulations are the tools used today to figure out possible scenarios but we need observations of actual protoclusters to constrain our guesses. Observations will be easier once the James Webb Space Telescope is launched but that's still at least two years away and astronomers, like the rest of us, are not patient. They push the capabilities of current observatories further than their original design. Necessity is definitely the mother of invention.

Want to see more of the stars at night and save energy? Shield your lights so that the light only goes down toward the ground. See www.darksky.org for how.

--
Nick Strobel
Director of the William M Thomas Planetarium at Bakersfield College
Author of the award-winning website www.astronomynotes.com

Late June 2016 at 9:30 PM looking south-southwest

Kern Community College District