Skytalk

Sunset comes at 4:35pm this week, then gradually later and later, though it won’t be until early January before we really start to see gains in hours of daylight.

5 weeks ago, astronomers across the world were surprised to find a sizable interloper zipping through the solar system. It’s not unusual to discover a new comet but it really raises eyebrows – and telescopes – when that object seems to come from an entirely different star system! Oumaumau’s trajectory, velocity, shape and suggested composition brand it as not being a comet, but an asteroid. Its shape, reflectivity and non-reaction to its close fly-by of the sun all point to the rockier options. Observers around the world dropped what they were doing to get the best possible view of this one because it seemed…well, odd.

Mars and Jupiter own the pre-dawn sky this week.

The planet Ross 128 is 11 light-years away and 1.35 times the mass of Earth and orbits its red dwarf star every 9.9 days.

Today is the 128th birth anniversary of Edwin Hubble – he determined that the universe has more than one galaxy and that those galaxies are moving outward, some at incredible rates of speed – revealing the previously unrealized expansion of the universe.

Jupiter, Venus, and Mars have the pre-dawn sky this week from 6am to sunrise. The moon and, strictly speaking Saturn and Mercury, hold court weakly and very low in the west at sunset.

Scientists have discovered a new suggestion of habitability in the ocean of Saturn’s moon Enceladus. Early doubts about tidal friction providing adequate heating for water jets is now supplemented by the suggestion that an unconsolidated core would allow penetration of water from the surrounding ocean and frictional heating derived from tidal interaction with Saturn. It’s valid to surmise this mechanism has been been functioning for a billion years and so a (relatively) warm ocean environment could’ve been in place for a billion years or more, maybe long enough to allow the development of life forms. On Earth, it’s estimated that the first microorganisms emerged after just 500 million years, with hydrothermal vents playing a key role in supplying heat and minerals.

A long-lasting supernova has been discovered – While supernovas typically are ‘one and done’, observations of a supernova that just won’t die indicate perhaps a new type of supernova, one that takes several explosions, maybe over decades, to blow off enough material to finally give up the ghost and begin to dim and cool.

Studies of asteroids are revealing that they might have a watery history. The DAWN spacecraft orbiting Ceres has provided data that suggests water was a major ingredient in the formation and evolution of the crust and mantle of the dwarf planet. This suggests that water is a much bigger player in the solar system than ever thought before.

A Philadelphia-sized lava tube has been identified on the moon, by the Japanese lunar orbiting satellite Selene. Gravity studies indicated its presence. This is an important discovery because Vice President Pence has indicated that the Trump administration will be far more focused on returning to the moon than with pushing for exploration of Mars. Tubes become important in that they can provide needed shielding of human outposts.

Not merely out-of-this-world, a comet from beyond our solar system came and went earlier this month.

We begin with the story of Spitz Laboratories, based in Chadds Ford, Pennsylvania. In the 1960s, the space race kicked off a nationwide surge of interest in astronomy. Schools began to build planetariums, and in Pennsylvania Spitz Laboratories built so many that in the 60s and 70s Pennsylvania had more in-school planetariums than New York and California combined.

Scientists have declared conclusively that Pluto has no rings. This is good news for their Horizons mission, as it means fewer obstacles for the craft to navigate as it heads towards its next destination, a space rock in the Kuiper belt.

Mars and Venus are visible in the predawn sky. Saturn can be seen in the Southwest after sunset.

This Saturday marks the 94th anniversary of the first public planetarium show given at the German model for The Franklin Institute, the Deutches Museum in Munich.

Mars and Venus are now well separated in the pre-dawn eastern sky 6:30 a.m. A very thin waning crescent moon is just to the left of Mars on Tuesday morning and sneaks past Venus during the day.

Elon Musk has released a new proposal for becoming a multi-planet species. He is advocating phasing out Falcon 9, Falcon Heavy and Dragon in favor of SpaceX’s BFR (Big F*****g Rocket-yes, really) project, which can serve as Mars transport, Lunar transport, ISS transport, and satellite delivery as well as SST Earth transport. The rockets will be reusable, bigger and cheaper to operate than any other rocket system ever. Supposedly. Musk says SpaceX can send the first two to Mars by 2022, and send four more to Mars, with explorers, by 2024. He also thinks he has a way to pay for this: Continued satellite launch services and ISS transport services.

The James Webb Space Telescope launch postponed until 2019. It was originally scheduled for launch in 2010/2011, then October 2018. Now due to payload integration schedule challenges, Spring 2019 looks like the next target period for launch. It’s critically important to get everything not just right, but perfect. Unlike many other missions that have allowed software uplinks and upgrades well into the mission after leaving Earth and even on-orbit servicing at 400 miles up as with HST, the JWST will be 930,000 miles up, well out of reach for any kind of servicing.

With sunset coming so much earlier now and the evening temps staying comfortable, you should find a way to get out to see a dark evening sky, especially the Milky Way. We’re viewing it almost on-edge as we look down toward Sagittarius.

Today, Dave and Dr. Pitts are stopping by the ice craters of Mercury, the planet closest to the Sun. Temperatures on Mercury typically hover around a balmy 800 degrees Fahrenheit, on the side facing the Sun. Yet there are at least 100 billion tons of ice on the little planet. How is this possible? The answer lies in Mercury’s lack of atmosphere. Without an atmosphere, heat is not conducted to the parts of the planet that aren’t getting direct solar radiation. The side of Mercury that doesn’t face the sun has a temperature of 300 degrees below zero. The abundance of ice can be found in craters at Mercury’s poles. The craters are always in shadow, so they receive no solar radiation.