The Valley’s dark skies yield not only the vast array of the cosmos, but also a vast array of information about the cosmos. The information is almost overwhelming in its sometimes mysterious and sometimes aha! details, so much so that choosing topics from that array for “Celestial Exploring” is fairly challenging. In this column however, let’s stay with what April skies are offering us awed and curious stargazers.
“Conjunction” is a word shared in the astrological sciences and in astronomical counsel. In the former, “conjunction” is a straightforward reference to the coincidence of two or more observable celestial bodies at the same celestial longitude. In the latter, the word is further loaded with reference to the astrological aspect of unified “planetary energies.” Here, we’re sticking to the astronomical sense of the word; there are multiple sources for you to read your astrological chart if you’d like.
Conjunction is an important feature of the April night skies. Earlier this week Mars and Saturn aligned near sunrise, near another of our planetary neighbors, Venus. Mars looked reddish, and Saturn, golden.
(Remember that the online star map at stellarium-web.org can provide precise Valley viewing guides.)
While not as spectacular as the late 2021 conjunction of Jupiter and Saturn, the Mars and Saturn alignment this week will soon be complemented by Jupiter’s dawn emergence.
Looking ahead into our April dark skies, other side-by-sides will be available. Tomorrow and Saturday evenings, the Moon passes Castor and Pollux in the constellation Gemini, the Twins. On Monday and Tuesday of La Semana Santa, the waxing Moon passes close to Regulus, the brightest star in Leo the Lion; on Friday and Saturday, Spica, the brightest star in Virgo the Maiden sits near the now full Moon.
Mercury joins the visible planet choreography around April 20, low in the west after sunset. It will steadily climb closer to the Pleiades every night until April 29, when they will be in conjunction.
Late in the month, the Moon will continue to play with planets, as the waning crescent Moon will lie west of Saturn on the morning of April 24 and east of Saturn on April 25, appearing between Mars and Saturn. On April 26 the Moon passes Mars in the morning, and the following morning will hang below Jupiter and Venus. Those two brightest planets will be in conjunction into early May.
That’s a lot of Moon and planet alignment to keep track of, but again, Stellarium and earthsky.org can keep viewers posted.
Perhaps the most anticipated sky-watching event of the month however, is the Lyrid meteor shower. That will be underway from April 15 to 29, appropriately peaking on Earth Day: Friday, April 22. The shower will radiate from the northeast before midnight when viewing is best between then and dawn.
It’s quite something to be able to view these events under our dark skies, yet we can also be humbled by the astronomical news this week that the long-exploring Hubble Space Telescope, not to be outdone by its soon-to-be-reporting companion the James Webb Space Telescope, has revealed the most distant and oldest star ever seen. (Cf. the coverage on skyandtelescope.com, etc) Astronomers have called the very ancient star, formed only 900 million years after the Big Bang, Earendel. J.R.R. Tolkien readers will recognize the tribute astronomers are making to his character Earendil, a half-elvin mariner, whose origins are in Germanic mythology, and are recounted fictionally in the posthumously-published Tolkein collection, The Silmarillion.
The opportunity to study conditions of the “early” universe will tell us more about where we came from, cosmically speaking, and the composition of the universe’s objects that continued—and continues—to make life possible.
More on telescopy in a later column; for now, lift up those eyes during clear April nights and be your own explorer of the dark skies with which we are gifted, and which we protect.
– W.A. Ewing