David Murr

Cabin Fever

It’s late February. The winter’s big snow has fallen and melted. These are the doldrums of winter, when we eagerly anticipate the coming warm light of spring.

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Waxing Crescent Moon & Earthshine

My Year in Cities 2013

Here’s my year in cities for 2013. These are places where we spent at least a night—the day trip list is quite a bit longer! Many of these were a part of our trek to coastal Maine and back over the summer. Cities marked with an * were visited multiple times on non-consecutive days.

I’d seen Jason Kottke do this over the years, but it was Joel Housman‘s tweet earlier today that prompted me go ahead and make my own list.

Here’s to travel in 2014!

The ISS Crosses Through Cygnus and the Milky Way

The International Space Station (ISS) appeared to pass through Cygnus & the Milky Way tonight, both arcing over our house.

Chinese Space Station, Tiangong-1, Passes Over Virginia

Catch Jupiter in the Evening Sky

Anyone out looking for Jupiter last night had an easy go of it, as it appeared to sit just about 5º away from the waning gibbous Moon. While the dazzling pale yellow point of light is striking even to the naked eye, a modest telescope or even a decent pair of binoculars, reveals four of Jupiter’s moons: Ganymede, Europa, Io, and Callisto (pictured here from bottom left to top right). Jupiter has a known total of 63 moons, but the four largest are known as the Galilean moons, named after Galileo Galilei, who first discovered them with his telescope in 1610.

If you missed seeing Jupiter and the Moon last night, don’t worry. They’ll both be close to one another again tonight, and Jupiter is easily visible as a brilliant object in the night sky all winter and throughout most of the spring. Right now, Jupiter rises in the east about an hour after sunset.

Lunar Orbiter Spots New Moon Crater

Back on March 17, 2013, observers with the Lunar Impact Monitoring Center noticed a meteoroid impact on the Moon. At about +4 magnitude, it was the brightest impact they’d seen in the eight-year history of the program. So recently, the Lunar Reconnaissance Orbiter, or LRO, made a pass over the area of Mare Imbrium where the impact occurred and photographed the brand-new crater. And if that’s not cool enough? If you have the right equipment — namely a decent-sized telescope and sensitive video camera — you can, as an amateur, contribute to the lunar monitoring project!

For the details, head over to Space Geek and check out the before-and-after comparison animation.

Read: LRO Finds New Crater on the Moon, Caused by Meteoroid Impact Observed on Earth on SpaceGeek.io

How to Spot the ISS

Just posted over on Space Geek: “How to Spot the International Space Station (ISS)” — one of those questions I get a lot. Well, here’s the answer!

Get Ready for the 2013 Geminid Meteor Shower!

You know the old saying “we saved the best for last”? The end-of-year Geminid meteor shower could certainly be considered one of the best. Along with the summertime Perseids, the Geminids tend to feature the most meteors. Last December’s shower was impressive — as I noted at the time, it was easily one of the best I’ve seen in recent memory.

This year, the Geminid meteor shower peaks on Friday, December 13 and Saturday, December 14. Unfortunately, the shower will be sharing the sky with the Moon much of the night, making fainter meteors harder to see. But with an estimated 120 meteors per hour visible under ideal conditions, and a typically high number of fireballs, it’s still well worth heading out.

What Is a Meteor, Anyway?

A meteor is a small piece of dust from space that enters the Earth’s atmosphere. Although these particles are usually tiny — most fall somewhere between the size of a grain of sand to a small pebble — they collide with the air that blankets our planet at incredible speed, causing them to burn up high above our heads. It’s this spectacular disintegration that we see as a so-called “shooting star.”

Although sporadic meteors can be seen here-and-there on practically any night from an area with reasonably dark skies, meteor showers occur when the Earth’s orbit crosses paths with a concentrated stream of cosmic dust. Most of this debris is left over from comets; the Geminids are unique though, as it’s one of the few showers that originates from dust from an asteroid (in this case, one called “3200 Phaethon“). That’s unusual because asteroids typically don’t have dusty tails that follow them around.

What Do I Need to Watch a Meteor Shower?

Very little, actually!

One fairly common misconception is that you need a telescope to watch for meteors. The truth is, you already have everything you need to enjoy the show: your eyes! Binoculars and telescopes are great for getting a detailed look at objects that appear to move slowly across the sky, like the Moon, planets, stars, and nebulae. But meteors are usually visible for only a fraction of a second and quickly move across a relatively large swath of sky, so using a telescope will actually make one harder to spot.

Aside from your own eyeballs, you’ll want to have a few other things.

After arriving at your observing site, give your eyes at least 15–30 minutes to adjust to the darkness so you can be sure to see fainter meteors.

Where and When Do I Look for Meteors During the Geminids?

The not-so-helpful answer is: everywhere! Meteors can appear anywhere in the sky, but they will all appear to originate from a point in the sky called the radiant. The reason this particular shower is called the “Geminids” is because the meteors appear, from our vantage point here on Earth, to radiate from the constellation Gemini. So you may want to locate Gemini first and scan the skies in that direction. But remember, you’re likely to see meteors even on the other side of the sky — they’ll just appear to be “coming” from the direction of Gemini. On the morning of December 13, the easiest way to find Gemini will be to look for Jupiter, which will be the brightest object in the western sky, just above the easily-recognizable Orion.

Although the Geminids will be visible practically all night during the peak, the best time to watch this particular shower is probably during the early morning hours, after the moon sets, on December 13 and 14. On December 13, that’s about 4 AM. The next morning, it’s about 4:45 AM. Heading out around 3–3:30 on either morning is a good bet. The twilight of dawn won’t begin to encroach until about 6 AM.


Sprites: “At the Edge of Space”

During powerful thunderstorms, red tendrils of light called “sprites” sometimes form — for just a tiny fraction of a second — high in the Earth’s mesosphere. This is the layer of our atmosphere that lies above the stratosphere, where jet airplanes typically fly, but not quite in what we consider “space.” Faint appendages from the main body of a sprite sometimes briefly hang down into the stratosphere. These ghostly, scarlet apparitions are caused by an underlying discharge of intense lightning and form above the top of the thundercloud. Because they’re so ephemeral, they were only first captured on film 24 years ago, in 1989.

More recently, Mike Hollingshead captured a fantastic image of a red sprite while taking photos of the aurora borealis in Omaha, Nebraska, while photographer Jason Ahrns has taken numerous photos of sprites (12) while flying aboard an aircraft. These are just a few beautiful examples.

The PBS program NOVA recently aired At the Edge of Space, an hour-long look at sprites. The show is well worth watching for the stunning visuals alone, but even more for the in-depth look at the work of scientists to uncover the nature of these of this fascinating phenomenon.