Saturday: Has there ever been life on Mars? Astronomers don’t know. But the Mars Curiosity Rover has been digging up some strong evidence that Mars was hospitable to life in the past. At the end of 2012, the first drilling assignment for Curiosity found clay-like minerals that form in the presence of water. In December 2013, scientists announced the strongest evidence yet for an ancient fresh-water lake in Gale Crater. Planetary geologist John Grotzinger said that Earth microbes could have thrived in this lake if they were placed there. Last year, astronomers at the European Southern Observatory’s Very Large Telescope in Chile found evidence that Mars was once had an ocean that held more water than the Arctic Ocean and covered a greater percentage of Mars’ surface than the Atlantic Ocean does on Earth. Finally, last month, Curiosity used its new drilling technique to drill into a Mars rock for the first time in 15 months. Watch a short video about the new drilling technique at https://goo.gl/u6N7N1 Watch reddish Mars, itself, two fists held upright and at arm’s length above the south-southeast horizon at 6:30 a.m. Yellowish Saturn is about a half a fist to the left of Mars. They will move closer together in the sky over the next few days.
By the way, the name of the observatory in Chile really is Very Large Telescope. See for yourself at http://www.eso.org/paranal.
Sunday: Astronomers are often fascinated with large objects. Planets that could fit 1000 Earths (Jupiter). Stars that would fill up the entire inner Solar System (Betelgeuse). Galaxies with 400 billion stars (Milky Way). But what about the smallest objects? One of the smallest stars is Proxima Centauri, the closest known star other than our Sun. It is about 12% of the mass of the Sun. Last year, astronomers even announced the discovery of an Earth-sized planet orbiting Proxima Centauri indicating that even very small starts can have planets. The smallest theoretically possible star would be about 7.5% of the mass of the Sun. Any smaller and it could not support fusion reactions. For more on small stars, go to http://goo.gl/EHBdOX.
Jupiter, the object that will fit 1000 Earths is a half a fist above the east-southeast horizon at midnight.
Monday: Orion still has a prominent spot in the nighttime sky. The belt is three fists above due southwest at 9 p.m.
Tuesday: Venus is one fist above the west horizon at 8 p.m. Use Venus and a pair of binoculars to try spot the planet Uranus. First, find Venus with your binoculars. With Venus at the center of the field of view, Uranus will be to the upper left, less than half way from Venus to the edge of the field of view. Don't be disappointed if you can't find it. The setting Sun and the atmosphere will make it tricky.
Wednesday: April is Global Astronomy Month (GAM). While many astronomy experiences come from looking up, you can also experience astronomy looking down… at pen and paper. GAM has numerous arts initiatives and is looking for contributors. Even if you’ve never written a poem before, this is your opportunity to express your love for astronomy in a unique way and possibly share it with others. Go to https://astronomerswithoutborders.org/gam2018-programs/astroarts.html for more information about the AstroPoetry and AstroArt contests. The AstroPoetry Contest has already started so don't delay!
Thursday: If the National Enquirer was around in Galileo’s day, it may have featured the headline: “Saturn has love handles; Opis leaves him for a much hotter starlet”. When Galileo first observed Saturn through a telescope, he reported objects that looked like bulges on either side of Saturn’s midsection. He was actually seeing Saturn’s rings through less than ideal optics. Saturn is two fists above the south-southeast horizon at 6 a.m., about two finger widths to the left of the slightly brighter Mars.
Friday: If you recently promised to do something "once in a Blue Moon", it is time to pay up. Tonight's Full Moon is the second full moon of the month, which some sources call a Blue Moon. If you don't want to do what you promised, you will want to quote the historical Blue Moon definition which states a Blue Moon is the third Full Moon in a season with four Full Moons. By this definition, the next Blue Moon is May 18, 2019. For more about Blue Moons, go to .https://www.space.com/15455-blue-moon.html.
The positional information in this column about stars and planets is typically accurate for the entire week. For up to date information about the night sky, go to https://nightsky.jpl.nasa.gov/planner.cfm.
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