We generally think of weather phenomena (e.g., snowstorms, hurricanes, clouds) as confined to the lower atmosphere. Previous posts have described CWG’s selection of top weather events (D.C. area, national, and international) of 2011.
But we also live within the “atmosphere” of the sun, and solar effects give rise to phenomena via the interplanetary magnetic field and the solar wind – space weather - which range from visually spectacular auroral displays to consequential (perhaps disastrous) disruptions in communications, power grids, satellite operations etc.(link)
Space-related events also make their mark on our collective experiences; for example, meteor showers, comets, solar/lunar eclipses, and manned and unmanned space exploration.
This selection of 2011’s top space weather and astronomy events doesn’t necessarily represent the most scientifically significant or historic set of a much larger set of possible choices. Rather, it is simply my personal list of highlights as an all-things space enthusiast - not far below enthusiasm for all-things (terrestrial) weather related.
Sun roars to life
Not withstanding some premature speculation that the sun might never “wake up” from the surprisingly quiescent and extended (5 year) period of the recent minima in the sun’s 11-year solar (sunspot) cycle, the sun roared into life in 2011. The past year was characterized by resurgence of sunspots, powerful solar flares and coronal mass ejections (CMEs), with the surge in solar activity expected to increase and eventually peak in 2013.
The largest solar flare in years exploded from the sun in August but was outdone by a “monster” solar outburst on November 3. Fortunately (luckily!), this and other significant flare-ups in 2011 were not facing earth directly so that the storm of charged particles ejected from the flares (CMEs) did produce any especially consequential effects. Though smaller, scientists rate the solar flare on June 7 as “epic making” in the context of a unique (never observed before) CME displaying perplexing behavior characterized by huge waves of plasma roaring off the sun only to rain back down onto the solar disk.
A number of comets crashed into the sun in 2011 never to be seen again. On May 10 one such “death dive” was the first captured on video (Note: the massive explosion on the sun immediately afterwards is considered unrelated, i.e., coincidental). Most fascinating was the survival of comet Lovejoy’s close encounter with the sun. Defying all odds – and fatalistic expectations of scientists – comet Lovejoy dove to within 87,000 miles of the sun’s surface on December 15 but re-emerged on the other side of the sun and continued its trek into space.
Unusual total lunar eclipse
The longest lunar eclipse in over 10 years dominated the attention of sky watchers the night of December 10. While not visible to those of us on the East Coast, it made for a spectacular show for those viewing directly (e.g., western U.S.) or virtually via web broadcasts. Especially eye catching was the red hue of the moon – rather than total darkness, even when the moon was completely shadowed by Earth. This effect results from atmospheric “dust” redirecting sunlight to fill the dark behind Earth’s shadow with the reddish, sunset-like glow.
What has been described as the “farthest-reaching auroral shows in years” occurred unexpectedly on October 24th with sightings in Maryland and Virginia and as far south as south as Arkansas. A specific and unpredicted (unpredictable?) alignment of the Earth’s magnetic field with that an otherwise not terribly significant CME, combined with darkening or dark and clear skies over much of the U.S., resulted in an awesome auroral display.
An especially unique view of an auroral display was provided by the surreal video of the southern lights, known as Aurora Australis, taken by the crew of the International Space Station on Sept. 17th.
Related: International Space Station around the world spectacle (video)
NASA’s Voyager spacecraft reaches edge of solar system
Remarkably, 33 years after its launch, Voyager 1 (with Voyager 2 not far behind) reached what’s considered the edge of the solar system - 17.9 billion miles from sun - where charged particles streaming from the sun (solar wind) are slowed to near zero by the pressure of interstellar gas. Most newsworthy is remembrance that, in 1990, Voyager 1 photographed the iconic image immortalized by Dr. Carl Sagan of the “pale blue dot”, the Earth appearing as an infinitesimally small point of light in the vastness of space only 4 billion miles away at the time.
Los Angeles-like haze surrounding Titan
Suppose the photochemical haze that often obscures the sky over Los Angeles but far worse surrounded the entire Earth. It might look like the haze permanently blanketing one of Saturn’s moons, Titan, as shown in an image from early December. Titan is the only moon in our solar system with an atmosphere worthy of mentioning. This atmosphere comes complete with lightning, drizzle and occasionally downpours of, not water, but liquid methane which collects and flows in Titan’s version of lakes and rivers.
First planet found in the habitable zone of a sun-like star!
Among the most intriguing questions in all of science is whether life (as we know it) can/could/does exist on planets beyond the solar system. An increasing number of planetary objects are being found in deep space, but it was in December that NASA confirmed discovery of the first extra-solar planet in the “habitable zone,” the region around a star where liquid water could exist on a planet’s surface. Water, of course, is only one of untold millions of ingredients and factors (including a planet’s weather and climate) necessary (but not necessarily sufficient) for life, especially “intelligent” life to develop and evolve.
Surfer waves spotted on the Sun
What appear to be visions of iconic surfers’ waves have been observed rolling along the atmosphere of the sun (best seen on video starting at 1:50 minutes). Though appearing small – relative to the size of the Sun – these waves are about the size of the continental U.S. They are initiated by the process called Kelvin-Helmholtz instability, the same mechanism responsible for waves on the surface of water, unusual cloud patterns (on Earth and the planet Saturn), etc, whenever two fluids of distinctly different densities flow by each other.