Bakersfield Night Sky — April 5, 2025
Tickets are on sale for the last shows of the spring season at the William M Thomas Planetarium: Dynamic Earth on April 10 and Black Holes on April 24.
Jupiter will be the first star-like object you see in the evening after sunset with a brightness of –2.1 on the magnitude scale astronomers use, where smaller (or even negative) numbers are brighter than larger positive numbers. It will be above the head of Taurus high in the west. The next object that’ll appear will be the brightest true star, Sirius (magnitude –1.4) at the nose or neck of Canis Major (depending on how you connect the dots) low in the southwest. The star chart above shows the view at 9 p.m. Orange-red Mars is high in the south just to the left of Pollux on the east (left) side of Gemini. The herald of spring, the constellation Leo, is high in the southeast.
The waxing gibbous moon will be to the upper left of Mars. They’ll be close enough in the evening to just fit within the same field of view of your binoculars. The moon and the stars Pollux and Castor will be approximately lined up on the sky. The following Saturday, April 12, the full moon will be very close to the brightest star of Virgo, Spica. With a magnitude of –0.3, you should still be able to see Spica just above the full moon. The moon and Spica are so close together this time that some of Central America and most of South America will actually see the moon cover up Spica!
On the planet Mars, the Curiosity rover in Gale Crater re-examined a sample of rock it drilled into in May 2013 to discover the largest organic compounds yet seen on Mars. The compounds are decane, undecane, and dodecane that are long-chain hydrocarbons with 10, 11, and 12 carbons bonded to hydrogen, respectively. These hydrocarbons could be fragments of fatty acids that are building blocks of life. This does not mean that Curiosity discovered past life but it does show that Mars had even more of the ingredients that life could have used to get started than we have found previously. On Earth, fatty acids help form cell membranes and perform other functions.
The discovery increases the chances that large “biosignature” organic molecules (ones that could be made only by life) could be preserved on Mars even after tens of millions of years of exposure to intense solar radiation and oxidation. The Perseverance rover in Jezero Crater is caching rock core samples with the plan to eventually bring those samples back to Earth for us to analyze with the most sophisticated instruments in our labs. These instruments are much too large to send to Mars. While Curiosity drills into rocks to make a fine powder for it to analyze, Perseverance’s core samples are rock pieces about the width of your pinky. Any possible microfossils would be preserved in its samples.
Because the analysis technique that Curiosity uses involves heating of the powder, it’s quite possible that the decane, undecane, and dodecane molecules were broken off from larger molecules called undecanoic acid, dodecanoic acid, and tridecanoic acid, respectively. To be sure, we’d need to bring the samples back to Earth to analyze them with instruments that wouldn’t need to heat the samples. Although the instruments on Curiosity and Perseverance are really sophisticated, there’s only so much miniaturization we can do.
In other space exploration news, the Milky Way mapper spacecraft, Gaia, has now finished gathering data. Launched in 2013 by the European Space Agency, Gaia precisely measured the positions, distances, motions, and spectral properties of nearly two BILLION stars and other celestial objects to create the largest, most precise multi-dimensional map of our galaxy ever created. On March 27, Gaia’s control team at the Space Operations Center switched off the various parts of the spacecraft and sent it into a “retirement orbit” around the sun.
The final data release (number 4) will happen in 2026 and the final catalog will be released no earlier than the end of 2030. With such a rich data set, astronomers will be mining the data for decades to come.
Gaia had collected data for the past decade-plus from the L2 Lagrange point, 1.5 million kilometers from Earth in the opposite direction from the sun. At L2, a spacecraft can keep the sun, Earth, and moon behind them at all times to get a clear view of deep space while pointing the communication antenna back to Earth for a constant link with the eager humans waiting to see what new things it discovers. Gaia’s cold gas supply used for attitude control had been depleted, so it was time for it to leave its L2 station and be put in another orbit around the sun where there is no chance of it interfering with other missions at L2, such as the James Webb Space Telescope and Euclid. In addition to creating the largest map of the Milky Way, Gaia found evidence of galactic mergers, identified new star clusters, helped discover exoplanets and black holes, mapped millions of quasars and galaxies, and tracked hundreds of thousands of asteroids and comets.
As part of its decommissioning, the names of around 1500 team members who contributed to its mission were used to overwrite some of the back-up software stored in Gaia’s onboard memory. Personal farewell messages were also written into the spacecraft’s memory, ensuring that Gaia will forever carry a piece of its team with it as it drifts through space.
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Director of the William M Thomas Planetarium at Bakersfield College
Author of the award-winning website www.astronomynotes.com
