astronomyblog: Globular clusters: Messier 3, Messier 9 and…







astronomyblog:

Globular clusters: Messier 3, Messier 9 and Messier 15

A globular cluster is a spherical collection of stars that orbits a galactic core as a satellite. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes and relatively high stellar densities toward their centers.

The first known globular cluster, now called M22, was discovered in 1665 by Abraham Ihle, a German amateur astronomer.However, given the small aperture of early telescopes, individual stars within a globular cluster were not resolved until Charles Messier observed M4 in 1764. (To learn more, click here).

Credits: NASA, ESA, STScI and A. Sarajedini (University of Florida)

apod: 2017 October 16 GW170817: A Spectacular Multi-Radiation…



apod:

2017 October 16

GW170817: A Spectacular Multi-Radiation Merger Event Detected
Illustrative Video Credit: NASA’s Conceptual Imaging Lab

Explanation: Both gravitational and electromagnetic radiations have been detected in rapid succession for an explosive merging event for the first time. Data from the outburst fit well with a spectacular binary neutron-star death-spiral. The explosive episode was seen on August 17 in nearby NGC 4993, an elliptical galaxy only 130 million light years distant. Gravitational waves were seen first by the ground based LIGO and Virgo observatories, while seconds later the Earth-orbiting Fermi observatory detected gamma-rays, and hours after that Hubble and other observatories detected light throughout the electromagnetic spectrum. Pictured is an animated illustrative movie of the event’s likely progenitors. The video depicts hot neutron stars as they spiral in toward each other and emit gravitational radiation. As they merge, a powerful jet extends that drives the short-duration gamma-ray burst, followed by clouds of ejecta and, over time, an optical supernova-type episode called a kilonova. This first coincident detection confirms that LIGO events can be associated with short-duration gamma-ray bursts. Such powerful neutron star mergers are thought to have seeded the universe with many heavy nuclei including the iodine needed for life and the uranium and plutonium needed for nuclear fission power. You may already own a souvenir of one of these explosions – they are also thought to be the original creators of gold.

∞ Source: apod.nasa.gov/apod/ap171016.html

neaq: Flowerhat jellies usually lazy around on the bottom of…



neaq:

Flowerhat jellies usually lazy around on the bottom of their exhibit or perched in the sea grass habitat. But this one is definitely trying to get someplace!

#VisitorPicture by Jacqueline Meyncke Risch #regram #likewhoa #ocean #animal #video #jellies #flowerhat #brainless #boneless #newenglandaquarium #boston #massachusetts (at New England Aquarium)

vintagecongo: From the documentary Forest Of The Dancing…



















vintagecongo:

From the documentary Forest Of The Dancing Spirits [watch trailer here]

The Aka (BaAka) are one of the indigenous people of Congo. An Aka elder tells the story of how Toli, the first woman discovered men

*Within the context of the DRC: Indigenous Peoples is the term accepted by the government and civil society organisations when referring to the P*gmy people of the Democratic Republic of Congo (DRC).They are found in ten of the country’s eleven provinces and are divided into four main groups: the Bambuti (Mbuti), the Bacwa (Baka), the Batwa (Twa) of the west and the Batwa (Twa) of the east.*