Looking Up column: Bright stars still shine on hazy nights
Hazy skies have been seen across most of the United States this past week, as the jet stream carried smoke from the extraordinary wildfires in the Pacific Northwest.
Incredible orange sunsets have resulted, as we look west towards the source of the smoke sent aloft far above our heads. The jet stream moves eastward at altitudes of about five to nine miles.
We can pause to consider the great loss thousands of people have been experiencing due to the fires, as we are reminded of their plight when we step out after dark on what should be a clear, starry night.
This past week, there were indeed very few stars visible, only the brighter ones feebly shining. The starlight, after passing through space from anywhere from dozens to over a thousand years, penetrated this last barrier to reach our eyes.
Particulate matter - dust - fills the Milky Way galaxy. Dust and gas make up enormous clouds called nebulae, spread through the spiral arms. On a very clear, dark evening in the summer and fall, we can witness the extensive, black “gaps” in the hazy Milky Way Band. Not gaps at all, this is dark nebulae, silhouettes obscuring or dimming the starlight beyond.
Yet, the most brilliant shine through on any but the truly cloudy nights.
This past week, I could easily detect the bright stars Vega, Deneb and Altair, although all three were diminished.
In my semi-rural village, I was able to see down to about +2 magnitude, when looking high up, where there is the least atmosphere. The further down we look in the sky, sunlight, moonlight and starlight must pass through thicker parts of our blanket of air.
Overhead I could see most of the stars of the Northern Cross pattern with the constellation Cygnus the Swan. To visualize, second magnitude is the brightness of most of the stars of the Big Dipper, or the three stars marking the famed “Belt” of Orion.
The bright planets also shined through. You could count on the king of the planets, Jupiter, which is magnitude -2.5. Jupiter is visible in the southern sky after dark, this month. To the left, I could just make out Saturn, magnitude +0.4. This planet would ordinarily be easy to see, but from mid-northern latitudes, Saturn and Jupiter are fairly low in the sky.
I didn’t see Mars, low in the east when I was outside, due to the hill. Mars, however, is very bright right now, -2.2, as it heads towards closest passage with the Earth on Oct. 6.
The brightest planet of all is Venus, currently a fiercely bright -4.2, and quite high in the east as dawn begins. Surely, from the Eastern States at least, the haze could not stop either Mars or Venus.
Volcanic eruptions can also spread dust high in the stratosphere, blanketing the world and reddening our sunsets and sunrises. The 1883 eruption of Krakatoa, one of the most destructive known, led to an average lowering of summer temperatures in the Northern Hemisphere by 0.72 degrees F.
Total lunar eclipses vary in redness and brightness, depending on dust high aloft in our atmosphere, where the sunlight must filter through to reach the moon when passing through Earth’s shadow.
The planet Earth has no monopoly on dust and clouds. Mars has a very dusty atmosphere, kicked up by its winds. Images taken from space probes that have landed show an amazing pale orange sky, in keeping with the overall hue of the planet.
Mars orbits Earth once in about two Earth years; not every pass is close. Astronomers, both the hobbyist with a good telescope and the professional, hope that during this fairly rare close passage, one of those infamous Martian dust storms does not kick up. On occasion, enormous dust storms have spread around Mars, almost completely obscuring the surface details we could otherwise detect with our telescopes.
Obviously, the stargazing is lousy on Mars at times like these!
Although anyone looking forward to seeing stars may complain when it is cloudy on Earth, consider that Venus, Jupiter, Saturn, Uranus and Neptune are perpetually shrouded with dense clouds.
As our hearts go out to the wildfire victims and hope the fires are extinguished soon, we can be patient with the haze, a reminder we live on a small world where we share so much in common.
Meanwhile, the Earth’s clouds, so necessary for rain and snow as well as cooling the surface, thankfully break up at times to give us windows to the universe beyond.
Look west for the crescent moon the next few evenings, leading to first quarter on Sept. 23.
Keep looking up at the sky!
Peter Becker is managing editor at The News Eagle in Hawley, Pennsylvania. Notes are welcome at firstname.lastname@example.org. Please mention in what newspaper or website you read this column.