Science is the poetry of Nature.







Contributing Authors
Posts tagged "cosmic"

ikenbot:

Galaxy Evolution Discovery Surprises Scientists

Disk galaxies like our own Milky Way put the finishing touches on their stunning shapes relatively recently, a new study suggests.

Image: This spectacular image of the large spiral galaxy NGC 1232 was obtained on Sept. 21, 1998, during a period of good observing conditions. Credit: ESO

The find will likely surprise many scientists, who had thought such galaxies had been static for more than half of the universe’s 13.7-billion-year existence.

“Astronomers thought disk galaxies in the nearby universe had settled into their present form by about eight billion years ago, with little additional development since,” lead author Susan Kassin, of NASA’s Goddard Space Flight Center in Greenbelt, Md., said in a statement. “The trend we’ve observed instead shows the opposite — that galaxies were steadily changing over this time period.”

Kassin and her colleagues used NASA’s Hubble Space Telescope and the Keck Observatory in Hawaii to study 544 blue galaxies, whose color indicates that stars are forming within them.

They found that the most far-flung, ancient galaxies tend to be the most disordered, with organization steadily increasing as galaxies are observed closer and closer to the present day. Over time, the galaxies’ rotation speeds increase, and they settle into proper, well-behaved disks.

The trend holds for galaxies of all masses, but the biggest systems are always the most highly organized, researchers said.

“Previous studies removed galaxies that did not look like the well-ordered rotating disks now common in the universe today,” said co-author Benjamin Weiner of the University of Arizona. “By neglecting them, these studies examined only those rare galaxies in the distant universe that are well-behaved and concluded that galaxies didn’t change.”

Full Article

subatomiconsciousness:

Polar and equatorial views of Earth, the aurora, the equatorial airglow bands, and the geocorona. Two 30° x 120° nadir-centered images show Earth and its faint lights at vacuum-ultraviolet wavelengths. Features of Earth’s disk (dayglow from the sunlit atmosphere, auroral oval, and equatorial airglow) appear primarily in the emissions of atomic oxygen at about 130.4 and 135.6 nm and of the LBH bands of molecular nitrogen, while beyond the limb the instrument responses are entirely due to solar Lyman radiation resonantly scattered by Earth’s extended hydrogen atmosphere, the geocorona.

The image in the left panel shows an active auroral oval on 14 October 1981 at 2017 UT following the onset of a substorm at local midnight. Spacecraft altitude is 16,500 km at 67° N latitude. The image in the right panel provides a view of Earth’s dark hemisphere at 0222 UT on 16 February 1982 while the sun is behind Earth. Spacecraft altitude and latitude are 19,700 km and 13° N, respectively. The northern auroral oval forms a halo of light above the limb of Earth, while the equatorial airglow bands in the premidnight sector straddle the magnetic equator. Isolated points of light in both images are VUV bright stars.

http://www-pi.physics.uiowa.edu/sai/gallery/

Type I:

A civilization that is able to harness all of the power available on a single planet — has approximately 1016 or 1017 Watts available. Earth specifically has an available power of 1.74 ×1017 W (174 peta watts, see Earth’s energy budget). Kardashev’s original definition was 4 ×1012 W — a “technological level close to the level presently attained on earth” (“presently” meaning 1964).

Type II:

A civilization that is able to harness all of the power available from a single star, approximately 4 ×1026 W. Again, this figure is variable; the Sun outputs approximately 3.86 ×1026 W. Kardashev’s original definition was also 4 ×1026 W.

Type III:

A civilization that is able to harness all of the power available from a single galaxy, approximately 4 ×1037 W. This figure is extremely variable, since galaxies vary widely in size; the stated figure is the approximate power output of the Milky Way. Kardashev’s original definition was also 4 ×1037 W.

Type IV:

A civilization that has harnessed the power of its supercluster, or “the largest gravitationally bound structure it originated in.” For the Local Supercluster, this would be approximately 1042 W. Dr. Michio Kaku has discussed a type IV civilization, which could harness “extragalactic” energy sources such as dark energy, in his book Parallel Worlds.

Type V:

A civilization that uses the entire resources of its respective universe.

"We had no equals. We controlled the fundamental forces of the entire universe. Nothing could communicate with us on our level."