One other semester is completed at Bakersfield School and the William M. Thomas Planetarium completed its fall schedule of reveals Wednesday with “Season of Gentle.” Only one snag this season as a consequence of issues with the movie file prompted the postponement of the Mars 1001 exhibiting. It’ll be proven within the spring season of reveals that can begin up in mid-February. Within the meantime I’ll be having fun with the winter break with my daughters, who’re flying house and reveling in fresh-squeezed orange juice from domestically grown tree-ripened oranges.
One other factor to take pleasure in are the sensible stars of the winter constellations corresponding to Orion, Taurus, Canis Main, Auriga and Gemini. Orion will already be up when the sky is darkish sufficient to see stars. The connected star chart reveals the sky for 9:30 tonight when the final of the constellations of the Orion group, Canis Main, is totally above the horizon. Should you comply with the road from Orion’s belt down, you’ll come to the brightest star within the night time sky, Sirius, which can also be the closest star we are able to see with the unaided eye from Kern County.
An excellent nearer star seen from Bakersfield is Barnard’s star within the constellation Ophiuchus, however it requires a telescope to see since it’s a purple dwarf star shining with simply 1/2500 the solar’s luminosity. Sirius, however, shines with about 25 occasions the solar’s luminosity. If we have been orbiting Sirius on the similar distance as we orbit the solar, the temperature on Earth can be nearly 295 C (over 560 F) with out contemplating any type of greenhouse impact.
The temperature calculation I simply gave makes use of a simplified system that features simply the gap from the solar, the solar’s luminosity, and the reflectivity of the planet (referred to as the “albedo” in astro-speak). For the solar, the system provides a temperature for Earth of -19 C. Sure, under the freezing level of water. The Earth has an environment that traps a number of the vitality radiating outward from the nice and cozy floor in what’s referred to as a greenhouse impact.
As with most issues in life, a greenhouse impact sparsely is a advantage. We want some to maintain the floor temperature of Earth heat sufficient for liquid water to exist. A greenhouse impact in extra shouldn’t be good for human civilization due to the disruptions in regional productions of meals and the availability of contemporary water.
As astronomers think about which exoplanets are within the “liveable zones” of their stars — vary of distances by which the floor temperature of the planet would enable liquid water to exist — they might embrace numerous concentrations of water vapor, carbon dioxide, methane, ozone and nitrous oxide in a planet’s environment to give you doable liveable zone boundaries.
One other approach is to calculate the liveable zone’s interior boundary as that for a planet with zero greenhouse impact in operation and the liveable zone’s outer boundary as that for a planet with a big greenhouse impact like we discover on Venus. That makes the liveable zone wider — an “optimistic liveable zone.”
Some analysis groups would possibly take a extra conservative strategy of sticking with a hard and fast greenhouse impact quantity for the whole liveable zone or completely ignore the greenhouse impact. That is why it pays to dig just a little deeper into any astronomer’s declare a couple of liveable zone planet to learn the way they’re calculating the liveable zone.
Monitoring carbon dioxide
Final week, the European international locations which can be members of the European Area Company (ESA) dedicated important boosts in funding for the house company. One of many greatest boosts can be with the Copernicus program of Earth-observing science satellites to look at human-made sources of carbon dioxide every day in addition to sea floor top and vegetation well being.
Whereas NASA pioneered efforts to trace carbon dioxide from house with the OCO-2 and OCO-Three missions, they’re designed to final only a few years and there are not any plans to maintain monitoring carbon dioxide with future missions. The ESA system will function for at the least 20 years and canopy wider swaths of the globe, masking any given level extra incessantly than the OCO missions.
Within the night time sky
In our night sky tonight, Venus and Saturn at the moment are the one planets seen as a result of Jupiter is misplaced within the twilight glow of the setting solar. Jupiter goes behind the solar on December 27. Saturn can also be dropping nearer to the solar whereas Venus climbs up away from the solar as Venus catches as much as Earth. Venus is now that sensible night star you see within the west. Within the early morning sky, Mars is climbing up away from the solar as Earth catches as much as it. Subsequent yr, Mars can be well-placed for NASA, ESA, China and the United Arab Emirates to launch their respective Mars missions.
One final word: The December solstice that marks the start of our winter will occur on Dec. 21. The solar will cease its southward drift among the many stars at eight:19 p.m. Pacific Time. Benefit from the longest night time of the yr and I want you a lot blessings this vacation season and an excellent 2020!
Contributing columnist Nick Strobel is director of the William M. Thomas Planetarium at Bakersfield School and creator of the award-winning web site AstronomyNotes.com.