Tuesday, 6 October 2015

The Melting Sphere

Wrong to self-indulge...

This Fragile Earth

The Ross Ice Shelf is the largest ice shelf of Antarctica (an area of roughly 487,000 square kilometres (188,000 sq mi) and about 800 kilometres (500 mi) across: about the size of France). It is several hundred metres thick. The nearly vertical ice front to the open sea is more than 600 kilometres (370 mi) long, and between 15 and 50 metres (50 and 160 ft) high above the water surface. Ninety percent of the floating ice, however, is below the water surface.

Most of Ross Ice Shelf is in the Ross Dependency claimed by New Zealand.

The ice shelf was named after Captain Sir James Clark Ross, who discovered it on 28 January 1841. It was originally named the Victoria Barrier by Ross after Queen Victoria and later the Great Ice Barrier, as it prevented sailing further south. Ross mapped the ice front eastward to 160°W.

Thursday, 24 September 2015

I'm on the subject of lenticular galaxies

NGC 4526 is a lenticular galaxy in the Virgo constellation that is seen nearly edge-on. The morphological classification is SAB(s)0°,which indicates a lenticular structure with a weak bar across the center and pure spiral arms without a ring. It belongs to the Virgo cluster and is one of the brightest known lenticular galaxies. The inner nucleus of this galaxy displays a rise in stellar orbital motion that indicates the presence of a central dark mass. The best fit model for the motion of molecular gas in the core region suggests there is a supermassive black hole with about 4.5+4.2
×108 (450 million) times the mass of the Sun.  This is the first object to have its black-hole mass estimated by measuring the rotation of gas molecules around its centre with an Astronomical interferometer (in this case the Combined Array for Research in Millimeter-wave Astronomy).

Supernova SN 1969E was discovered in this galaxy in 1969, reaching a peak magnitude of 16. In 1994, a Type 1a supernova was discovered about two weeks before reaching peak brightness. Designated SN 1994D, it was caused by the explosion of a white dwarf star composed of carbon and oxygen.

Tuesday, 22 September 2015

Perseus Arm - Milky Way

The Sun is near the inner rim of the Galaxy's Orion Arm, within the Local Fluff of the Local Bubble, and in the Gould Belt, at a distance of 8.33 ± 0.35 kiloparsecs (27,200 ± 1,100 ly) from the Galactic Center.

The Sun is currently 5–30 parsecs (16–98 ly) from the central plane of the Galactic disk. The distance between the local arm and the next arm out, the Perseus Arm, is about 2,000 parsecs (6,500 ly). The Sun, and thus the Solar System, is found in the Galactic habitable zone.

An In-between Galaxy

A lenticular galaxy is a type of galaxy which is intermediate between an elliptical galaxy and a spiral galaxy in galaxy morphological classification schemes. Lenticular galaxies are disc galaxies (like spiral galaxies) which have used up or lost most of their interstellar matter and therefore have very little ongoing star formation

They may, however, retain significant dust in their disks. As a result, they consist mainly of aging stars (like elliptical galaxies). Because of their ill-defined spiral arms, if they are inclined face-on it is often difficult to distinguish between them and elliptical galaxies. Despite the morphological differences, lenticular and elliptical galaxies share common properties like spectral features, scaling relations and both can be considered early type galaxies which are passively evolving, at least in the local universe.