This is a good time to remember the joys of midsummer astronomy, if only to divert our minds momentarily from hurricane-force winds, wrecked fences, downed giant spruces and snow.
I spent the balmy night of July 28-29 at the site in Tooele County that Utah astronomers call Lakeside, complaining to myself about the heat — with the air at 60 degrees, my camera’s temperature regulator could only get down to the freezing point. The cooler the camera is, the less noise is generated by its electronics and the cleaner the images.
I took sets of photos of the Draco Triplet galaxies until they sank low in the north-northwest and dawn was beginning to crack.
[Image of the Draco Triplet made the night of July 28-29, using my SBIG camera and LX200GPS telescope, from Lakeside Tooele County. For a larger version,click HERE. Photo by Joe Bauman]
The trio is about 100 million light-years away in the direction of the constellation Draco. They present a fine selection of types. From the top of my picture to bottom, they are: a spiral galaxy, NGC5981, seen edge-on; an elliptical galaxy, NGC5982; and a special type of spiral showing us its full face, NGC5985. They are “all within this single telescopic field of view spanning a little more than half the width of the full moon,” reported NASA’s Astronomy Picture of the Day site.
Amusingly, the site posted pictures of the Draco Triplet three times in about the last decade: June 8, 2001, May 6, 2006, and July 1, 2009, with captions that are nearly identical in places. Well, there are some differences. For example, one caption says these are called the Draco Trio because they are in “(you guessed it) Draco,” while the other captions say they are called that “(quite reasonably)” — those are NASA’s parentheses.
The number of galaxies bunched together is “far too small to be a galaxy cluster and has not been cataloged a compact group,” the captions add.
They are “all within this single telescopic view spanning a little more than half the width of the full moon.” Nevertheless, they’re apart far enough that with my telescope’s high magnification I had to take the images in two sets, first the upper section of the triplet, then the lower, and assemble them into a mosaic. Otherwise they wouldn’t have fit in a single view.
The lovely spiral at the bottom, NGC5985, is special because it’s a Seyfert galaxy, meaning its bright nucleus is believed to harbor an active, supermassive black hole. Seyfert galaxies are identified by unusual spectra of light from the center suggesting furious motion by hot gas.
Despite the grandeur of the three island universes, I’m much more awed by a pale dot that appears to the lower left of the upper galaxy, the edge-on NGC5981.The dot is a quasar, that is, a quasi-stellar radio source – something so far away that it looks like a star but really is an immensely strange object, a gigantic, feeding black hole. This one is designated SBS 1537+595 1.
[The dot indicated above is the quasar SBS 1537+595 1. This is a cropped version of the Draco Triplet image earlier in this blog. Photo by Joe Bauman]
Describing another quasar that was imaged recently, one called AMP 08279+5255, NASA said in a July 27 press release that is surrounded by “the largest and farthest reservoir of water ever detected in the universe. The water [in the form of water vapor], equivalent to 140 trillion times all the water in the world’s ocean, surrounds a huge, feeding black hole, called a quasar, more than 12 billion light-years away.”
The release explains that a quasar “is powered by an enormous black hole that steadily consumes a surrounding disk of gas and dust. As it eats, the quasar spews out huge amounts of energy.” The quasar the press release refers to “harbors a black hole 20 billion times more massive than the sun and produces as much energy as a thousand trillion sons.”
The name quasar indicates a radio source, but that’s only a holdover from the first examination of quasars by radio telescopes in the early 1960; these were found because they are powerful radio sources. But NASA’s Goddard Space Flight Center says most quasars are radio-quiet. “We also now know that many (perhaps all) quasars are small regions of intense activity within otherwise normal galaxies,” according to Goddard.
They seem to be a property of the early universe. No quasars are known nearby, but some astronomers speculate that the supermassive black holes in many galaxies, including the Milky Way, may have been quasars in their youth.
How far away is the quasar I photographed? The distance to these objects is judged by their red shift; according to consensus thinking among astronomers, the farther away a galaxy is, the faster it is receding from Earth and everything else.
When a train approaches blowing its whistle, the sound waves are compressed, giving it higher frequency and a shriller sound. When it passes and recedes, its sound waves are stretched out, making the whistle sound lower. This Doppler effect operates with light too: the faster something approaches, the bluer it is; the faster it recedes, the redder.
The red shift is used to measure the distance to far-off objects like quasars. (A minority school of thought holds that quasars may be material expelled violently from galaxies and only show a great red shift because they were thrown out at immense velocity.)
My view’s quasar has been measured with a red shift of 2.125120, according to the NASA/IPAC Extragalactic Database. If the majority opinion is right about red shifts, that means the light has been traveling toward Earth for 10.23 billion years. It started on this incredible journey, traveling 186,000 miles every second, when the universe was only 3.069 billion years old.
Astrophysicists calculate that the Big Bang happened 13.299 billion years ago and the solar system formed 4.5 billion years ago. The light captured by my camera blasted out of quasar SBS 1537+595 1 when the universe was about 23 percent of its present age. Our world would not begin to form for another 5.73 billion years.