Glows Before Dawn / Tomorrow’s Close Shave With Asteroid 2014 RC

A wreath of green aurora capped by a diffuse glow burns just above the northern horizon this morning before dawn. Can you spot the Big Dipper? Credit: Bob King

The moon’s bright and near full, but if you wait until after it sets, there’s still a sliver of dark sky before dawn. This morning a quiet arc of aurora glowed in the north while I did some comet hunting after moonset. Auroral activity has kicked up of late from the combined effects of solar outbursts called CMEs (coronal mass ejections) and coronal holes.

The softly luminous ‘finger’ of zodiacal light (left side) tilts upward this morning in early dawn to meet the Milky Way in northern Orion. You can spot the three Belt Stars at right. Jupiter is the bright “star” at lower left. The zodiacal light is centered on the ecliptic, the path followed by the sun, moon and planets across the zodiac constellations. Credit: Bob King

The aurora wasn’t the only thing setting the sky aglow. As fall approaches, so too the angle at which the ecliptic meets the eastern horizon at dawn. When that angle is steep, as it is now through early November, we get a good look at the zodiacal light. It looks like a fat finger or cone of diffuse light tilting up from the eastern horizon.

Like breadcrumbs dropped to mark a trail, comets shed dust particles each time they cycle about the sun. Asteroid collisions also contribute. The dust accumulates in the plane of the planets and glows by reflected sunlight. To see the zodiacal light while the crickets murmur at dawn is to witness the comings and goings of countless comets across generations of humanity.

With the Full Harvest Moon knocking on the door, we’re done with dark sky after tomorrow morning. Mark your calendar for September 22. Not only is that the first day of fall, but the zodiacal light returns to a dark sky and remains visible for two full weeks.

This graphic depicts the passage of asteroid 2014 RC past Earth on September 7, 2014. At time of closest approach, the space rock will be about one-tenth the distance from Earth to the moon. Based on brightness, astronomers estimate the asteroids’s size at 60 feet. Times indicated on the graphic are EDT or Eastern Daylight Time. Credit: NASA/JPL-Caltech

Something invisible to most of us is one its way to Earth’s skies tomorrow afternoon. That’s when the recently discovered asteroid 2014 RC rips across half the sky in a span of hours while making a very close approach to our planet. The approximately 60-foot-wide, house-sized space rock will skim the outer edge of the geosynchronous satellite belt only 25,000 miles (40,000 km) from the hairs on your head around 2:15 p.m. Eastern Daylight Time. It was discovered on September 1.

Map showing just how fast this asteroid will zip across the sky around the time of closest approach tomorrow Sunday September 7, 2014. 2014 RC moves from Aquarius (lower right) all the way to Puppis in just 12 hours. Created by Gianluca Masi using the SkyX Pro software. Click to enlarge.

Nothing to worry about here as the asteroid will safely pass by Earth. 2014 RC will return in the future, but no threatening passes have been identified. Though most of the really bad-boy 1-km or larger Earth-approaching asteroids have been discovered, many smaller ones remain large. An estimated 1 million NEOs (Near-Earth objects) in the 100-foot (30-meter) are still out there. Surveys like those carried out with the PanSTARRS-1 telescope in Maui, Hawaii and the Catalina Sky Survey are constantly on the lookout for them. At least once a month, a new Earth-approacher is found.

2014 RC will pass along the edge of the geosynchronous satellite belt, home to many weather and communications satellites. The chance of a hit is close to infinitesimal. Click for more information and detailed finder charts for the asteroid. Credit: SatFlare

Because 2014 RC will brush by Earth during daylight hours for the Western hemisphere, we’ll miss it. Observers in other parts of the southern hemisphere where it’s dark might spot it with a 6-inch or larger telescope as an 11.5 magnitude star moving as fast as a slow satellite through the field of view.

While most of us won’t see the asteroid in our own telescopes, plans are underway for radar imaging with the Goldstone dish in California. Italian astronomer Gianluca Masi will also have telescope trained on the space rock and feature it live on his Virtual Telescope Project site beginning today at 6 p.m. EDT. Take a look!

3 Responses

  1. Veronica

    I have a passion to collect (gather, buy) stones and minerals. In the last four years someone gave me an idea: I documented meteorite, which is a rare and valuable stone for scientists. In Sept. 2012, someone gave me a hunting dog. This dog, growing, needed to run. Then every day we went to the car and 15 km from where I lived and I stopped in a place with arable fields without weeds and wild shrubs. Let the dog run in his will on me, I take furrow after furrow and looked dark stones. The area is rich Hromite. At a time, finding some small stone (2 grams each) on the surface of the earth, I said: What beautiful pebbles! And they gather them for my collection. I always pocket a magnet, so I assembled easily and quickly. Question: Where can I send them for analysis? Are the only site that explain in layman’s rain of meteorites, Earth contact Halley’ tail. Thanks! Veronica.

    1. astrobob

      Hi Veronica,
      Thank you for writing. Since the stones are most likely not meteorites, I would suggest you bring your favorite rocks to a geology professor at the nearest university. Or you can find out the nearest “rock and mineral” club. If there are ever any mineral shows in your region, you can bring them there too and get an opinion. Good luck!

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