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[...] artificial skies of the 20th and 21st century. Will the ring of satellite debris eventually seed an ablation cascade, breaking down into a great artificial new reef of debris encircling the Earth? What will the [...]
The Sky is Waiting.
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Pictured is a Delta IV rocket launch from Cape Canaveral on November 21st, 2010. The image is a 20 second exposure taken at dusk, shot from about 100 miles west of the launch site. The launch placed a classified payload in orbit for the United States Air Force.
Difficult but not impossible to catch against the dawn or dusk sky, spotting an extreme crescent moon can be a challenge. The slender crescent pictured was shot 30 minutes before sunrise when the Moon was less than 20 hours away from New. A true feat of visual athletics to catch, a good pair of binoculars or a well aimed wide field telescopic view can help with the hunt.
The Sun is our nearest star, and goes through an 11-year cycle of activity. This image was taken via a properly filtered telescope, and shows the Sun as it appeared during its last maximum peak in 2003. This was during solar cycle #23, a period during which the Sun hurled several large flares Earthward. The next solar cycle is due to peak around 2013-14.
Located in the belt of the constellation Orion, Messier 42, also known as the Orion Nebula is one of the finest deep sky objects in the northern hemisphere sky. Just visible as a faint smudge to the naked eye on a clear dark night, the Orion Nebula is a sure star party favorite, as it shows tendrils of gas contrasted with bright stars. M42 is a large stellar nursery, a star forming region about 1,000 light years distant.
Orbiting the planet in Low Earth Orbit (LEO) every 90 minutes, many people fail to realize that you can see the International Space Station (ISS) from most of the planet on a near-weekly basis. In fact, the ISS has been known to make up to four visible passes over the same location in one night. The image pictured is from the Fourth of July, 2011 and is a 20 second exposure of a bright ISS pass.
Next to the Sun, the two brightest objects in the sky are the Moon and the planet Venus. In fact, when Venus is favorably placed next to the Moon, it might just be possible to spot the two in the daytime. Another intriguing effect known as earthshine or ashen light is also seen in the image on the night side of the Moon; this is caused by sunlight reflected back off of the Earth towards our only satellite.
A mosaic of three images taken during the total lunar eclipse of December 21st, 2010. The eclipse occurred the same day as the winter solstice. The curve and size of the Earth’s shadow is apparent in the image.
AstroEvent: A Wild Card Meteor Shower.
Comet 21P Giacobini-Ziner. (Credit: NASA).
Sure, everyone’s heard of the Leonids and the Perseids, but have you ever stood vigil for… the Giacobinids? Also sometimes referred to as the Draconids, this sporadic shower tends to go unnoticed on most years. Radiating from the circumpolar constellation Draco, the Giacobinids produce a lackluster <5 meteors per hour… so, why the fuss? Well, the Giacobinids have been known to occassionally put on a show approaching 1,000+ storm level activity, most notably on the years 1933, 1946, and most recently, 1998. This seems to occur with the perihelion passage of the showers’ parent comet 21P Giacobini-Ziner (hence the bizarre name). This occurs again in 2011, and it’s worth watching for storm level activity on either year surrounding that date. The Giacobinids arrive around October 7-8th, and the good news this year is that the Moon is New on October 7th. The radiant for this shower also transits in the late evening hours, so unlike many meteor showers, you may see increased activity shortly after dusk… will the Giacobinids perform this year? The only way to know for sure is to watch!
This week’s astro-word is Ablation Cascade. Not everything in the night sky that looks like a dust grain meteor is; a satellite on re-entry can mimic the same style of brilliant bolide fireball. Also sometimes referred to as the Kessler syndrome, this scenario was first theorized by NASA researcher Donald Kessler in 1978. The fear is that as the amount of space junk accumulates in Low Earth Orbit, (LEO) a threshold may be reached whereby the shrapnel from one satellite collision may serve to trigger more. Already, we’ve witnessed the first sat-on-sat collision recently, with the destruction of an Iridium and defunct Cosmos satellite. What would be the actual tipping point of orbital density is unclear. Ideas to “cleanup” LEO include using lasers to target larger fragments and requiring that newer satellites can either be de-orbited or have the capability to move into graveyard orbits when required. Space debris is a big concern for the International Space Station, currently by far the largest thing in LEO. Won’t that be a spectacle on that (hopefully far off) day when the ISS gets de-orbited?