Night Sky

Night Sky

By Collin O’Mara-Green

Meteor Showers

Credit: Sky and Telescope

Every year, as the Earth orbits around the Sun, our planet passes through the ancient paths of icy comets and rocky asteroids. Those objects have shed gasses and bits of rock which linger in space.When Earth runs into this trail of space debris, the atmosphere acts as a shield. If the collision between rock and air is fast enough, you get what we call a “shooting star” or meteor. It’s not a star at all; often it’s a rock the size of a grain of sand! The friction caused by the air causes it to glow and vaporize into a streak of light.

Although random space rocks can cause meteors anytime, these predictable intersections with old objects creates “meteor showers” with many shooting stars per hour. Dates are roughly the same each year, but the number of meteors can vary widely from year to year.

The next shower is tonight! The Eta Aquarids at about 50 faint meteors possible per hour. To observe, just find a clear sky and blankly look up. Your eyes will pick up on meteors all on their own.

Keep lookin’ up!

Night Sky

By Collin O’Mara-Green

Breaking news – Humans litter on Mars!

Did you know there is a remote-control helicopter on Mars! It recently took images of the Red Planet’s surface showing the aerodynamic backshell protecting it and the rover Perseverance on its entry into the Martian atmosphere.

It’s almost routine now to see images from the Mars rovers of the desert like landscapes they are exploring to better understand the geology, chemistry, and possible biology of a planet that once had oceans and rivers like Earth. This most recent rover Perseverance had a stowaway craft, Ingenuity, a small solar-powered, semi-autonomous twin rotor helicopter that has made a total of 26 short flights to date. Amazing!

But a by-product of robotic exploration of other planets is the litter and trash that is left behind in the landing process. To actually see this piece of tech and large parachute that slowed the rover to a safe landing speed is unreal, let alone a view from the skies of Mars.

Read more here: https://www.jpl.nasa.gov/news/nasas-mars-helicopter-spots-gear-that-helped-perseverance-rover-land

Keep lookin’ up!

Night Sky

By Collin O’Mara-Green

International Dark Sky Week

“Cityscape to the Milky Way
A lot of the outdoor lighting used at night is inefficient, overly bright, poorly targeted, improperly shielded, and in many cases, completely unnecessary. This light and the electricity used to create it are being wasted because it spills into the sky rather than being focused on the objects and areas that people need illuminated.” – Darksky.org

The world is losing its night skies. An unintended consequence of the wonder of electric light is the loss of natural light from distant stars. Modern lighting has allowed us to work and live beyond the window of sunrise and sunset, and without the safety issues of candlelight. This new light can also bounce upward, where the glow of the Milky Way becomes harder to see.

To raise awareness about light pollution, International Dark Sky Week is April 22-30, 2022. It’s a good time to learn how you can help your area have darker skies, and perhaps save a few dollars on power bills.

In big cities, some kids have never seen a truly dark sky. During the Northridge earthquake in LA, it’s said, when the city went dark after the electricity grid failed altogether, people asked if the glow in the sky caused the earthquake. They were seeing the Milky Way for the first time!

I would say parts of Sierra County would qualify for official dark sky status, likely those shielded from the glare of Sacramento, Reno, Grass Valley, and now Truckee I suppose. More at the official website: https://idsw.darksky.org/

Keep lookin’ up!

Night Sky

By Collin O’Mara-Green

Solar activity returns

While the Sun appears as a round glowing sphere in the sky, its glare masks lots of activity. The Sun, like all stars, is a ball of super-hot gases undergoing nuclear fusion. Hydrogen in a star’s core is subjected to intense heat and pressure resulting in the formation of helium and other heavier elements, including our own Sierra County gold from some other long ago star’s fusion.

In addition, the sun is rotating on its own axis every 27 days or so which is quite fast considering you could fit 1.3 million Earths inside. This rotation at the Sun’s equator is faster than at its poles, due to its composition of plasma (super-hot gas). The sun’s magnetic field is bent and warped by this difference in speeds.

Every 11 years or so, the sun’s magnetic field flips, resulting in increased solar activity like sunspots and solar flares. We are now entering a new period of solar activity, so look for more images from astrophotographers of the sun soon.

Keep Looking Up!

Night Sky

By Collin O’Mara-Green

Twinkle, Twinkle, little star…

The old nursery rhyme gets at a good observation. Stars do appear to twinkle as we look up to the night sky. This variation in brightness is mainly due to our atmosphere. Earth’s atmospheric layers are always in flux, moving with wind, humidity, and temperature. This constant change causes light traveling in a straight line from distant stars to suddenly bend or change direction as it passes through the atmosphere on its way to your eyes. Sometimes brighter with less interference, sometimes dimmer with more refraction.

The same phenomena occurs when looking at the bottom of the Downie or Yuba Rivers. If the water is calm and flowing smoothly, you can clearly see the riverbed with minor distorsion. But when the waters are raging and turbulent during spring melt, the bottom appears fuzzy or not visible.

In space, the stars don’t appear to twinkle, since there is no atmosphere. Future astronauts will need a new nursery rhyme about stars!

Keep looking up!