Stargazing 5-19

The night sky in mid-May.

The Californian

On Friday, the largest group of graduates (almost 1,000) walked across the stage at BC’s commencement. That’s about 300 more than the previous year and we also had the first baccalaureate degree graduates of any community college in California. Good things to celebrate!

Saturday night is a free public star party hosted by the Kern Astronomical Society at Barnes & Noble on California just west of Highway 99. In June, the free public star party will be at Panorama Park and then in July they’ll be back to the Park at River Walk to start the cycle over again. The moon will be a fat waxing crescent slightly over half a fist width at arm’s length below the Beehive Cluster in Cancer. The accompanying star chart shows what you’ll see Saturday night.

At 9 p.m., the two brightest planets, Venus and Jupiter, will be at about the same altitude above the horizon but opposite sides of the sky. Venus is now at the feet of Gemini and it will appear as a gibbous phase about 85 percent lit through the KAS telescopes. By the end of May, Venus will be in the middle of Gemini.

Jupiter in Libra is at its biggest and brightest a little over a week after opposition, when it was directly opposite the sun. That is also when we “lap” (or pass by) Jupiter in our inner faster orbit. Jupiter is retrograding (moving backwards with respect to the stars) as we’re passing by it. If the air is clear and steady, you might be able to see the Great Red Spot near the edge of Jupiter and a black spot on its northernmost band of brown clouds. That’s the shadow of Jupiter’s moon, Europa, passing in front of Jupiter.

Europa is the one that probably has a deep ocean of liquid water below its icy surface and will be the target of future astrobiology missions. There was a live webcast about Europa’s astrobiology possibilities held on Monday. Scheduled to launch in 2022, the Europa Clipper will have the instrumentation needed to determine if Europa has all the ingredients for life: an energy source, a liquid and organic compounds. Europa’s energy source is tidal flexing in Jupiter’s strong gravity field. The liquid is very likely water. It’s the presence of organic compounds that we’re not sure about. The red and brown blotches and cracks could be organic compounds welling up from below.

Eye on Mars

The Mars InSight lander is now on its way to Mars. Hitching a ride on the same rocket were two CubeSats each about the size of a briefcase. The pair, called “MarCO” (for “Mars Cube One”) are testing miniature spacecraft technology and will be the first deep-space CubeSats ever launched. Their radios, folding high-gain antennae, attitude control and propulsion systems are all experimental. If they work correctly, they’ll be able to relay information from InSight as it enters Mars’ atmosphere and descends to the planet's surface.

This seven-minute entry period is the most dangerous part of any lander’s mission to Mars. The majority of Mars missions have ended in failure due to landing problems, so the time period is aptly called “Seven Minutes of Terror.” After InSight lands safely (hopefully!), the lander will use the already-present Mars Reconnaissance Orbiter to relay information back to Earth as well as direct links to radio telescopes on Earth.

Another piece of Mars news is NASA’s plan to include a miniature helicopter with the Mars 2020 mission that will launch in July 2020. At just 4 pounds with the main body the size of a softball, this helicopter is carrying a light load: a camera, solar panels for power and a heater to survive the Martian nights. Twin counter-rotating blades will spin at almost 3,000 rpm, or about 10 times the rate of a helicopter on Earth due to Mars’ thin atmosphere. The density of air on the surface of Mars is the same as the Earth’s atmosphere at 100,000 feet altitude, or over twice as high as any helicopter has gone on Earth.

The helicopter for the Mars 2020 mission is just a technology test vehicle, so if it doesn’t work, the Mars 2020 rover will still be able to carry out all of its science mission, which includes searching for signs of ancient Martian life and assessing the resources and hazards for future human living off the land. The Mars 2020 rover will also collect rock and soil samples into containers for a future mission to return the samples to Earth.

One last item involves 3D imaging of a star formation cloud using some clever thinking. Because of their great distance, we have just a 2D view of interstellar molecular clouds. We can’t see a cloud from different points of view. However, astronomers analyzed the spacing of strings of clumped gas to show they are caused by oscillations of the cloud at resonant frequencies (similar to pressure waves in an organ pipe) and from that deduce the 3D size and shape of the gas cloud. I think it’s a good example of using clever thinking to overcome our physical limitations.

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