Bakersfield Night Sky — May 5, 2024
We’re now in finals week at Bakersfield College and the Planetarium will be closed for the summer. During May those looking for planets will need to get up early before sunrise. Although Jupiter is technically still an evening planet, it is now so close to the sun on our sky that it is lost in the twilight glow and dust/smog of the Bakersfield horizon. Jupiter goes behind the sun on May 18 and it’ll reappear in the early morning pre-dawn sky in mid-June.
This morning (May 5) before sunrise, three planets are visible in the east-southeast with a slender waning crescent moon in between them (see the star chart above). Mercury is very low in the east, so you’ll need binoculars to find it in the twilight glow. A bit further to the right about a fist-and-a-half at arm’s length is orange-red Mars and then another fist-and-a-half further right in the southeast is honey-yellow Saturn. The moon is about halfway between Mercury and Mars. Tomorrow early morning (May 6), an even thinner crescent moon will be to the left of Mercury. They’ll be about one binocular field of view apart from each other (or about 5 degrees). The moon will be at new moon position on May 7.
In the evening, observers will have to content themselves with the spring constellations of Leo high overhead in the south and the constellation trio in the east of kite-shaped Bootes with very bright Arcturus at the tail end, the backwards “C” of Corona Borealis, and the bow-tie pattern of the main part of Hercules with the beautiful globular cluster M13 at one of its edges. A waxing crescent moon will be in the western sky in the evenings after sunset from May 8 onward and reach first quarter phase on the night of May 14/15. By then it will be high in the south after sunset.
In astronomy research news, one interesting item is the discovery of dimethyl sulfide in the dust and gas escaping the Comet 67P/Churyumov-Gerasimenko by the Rosetta spacecraft. Although the Rosetta mission ended in late 2016, we’re still sifting through the rich data trove all these years later and making discoveries. Dimethyl sulfide is supposed to be a strong biosignature, a chemical compound that can only be made through biological processes. Well, so we thought.
Dimethyl sulfide (DMS) is emitted into the atmosphere by phytoplankton, giving sea air its characteristic odor from the aerosols in the air. It’s also responsible for the odor in sewers from the bacteria breaking down the waste in them. The fact that DMS is produced only by life on Earth was why there was a bit of buzz about possible detection or hint of DMS in the atmosphere of the exoplanet K2-18b last fall. The evidence is weak and more recent analysis of the James Webb spectra has shown that an uninhabited gas-rich exoplanet model could also match the spectra about as well.
Back to Comet 67P. A team led by Nora Hänni from the University of Bern, Switzerland announced at the EGU General Assembly in late April the discovery of DMS in Comet 67P’s coma (the atmosphere that forms around the dirty iceberg comet nucleus when it nears the sun). Comet 67P definitely does not have life on it, so there must be a non-biological way to produce DMS and, therefore, DMS is not the strong biosignature we were hoping for. Sigh!
Both of these stories, the DMS in Comet 67P and the work to find an alternative explanation for the spectra of the exoplanet K2-18b, illustrate the rigor and skepticism in how research scientists approach the question of extraterrestrial life. Before we say that we’ve found extraterrestrial life, we’ll do our darnedest to find a non-biological explanation for what we’ve observed with multiple independent teams doing the analysis. Only after we’ve exhausted the non-biological possibilities will we say we’ve truly found life. “Extraordinary claims require extraordinary evidence.” Now, if we could only bring that skepticism to bear when we hear claims in the political arena in this election year but that’s a subject for a Community Voices piece in the future.
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Director of the William M Thomas Planetarium at Bakersfield College
Author of the award-winning website www.astronomynotes.com
