Extinction RebellionExtinction Rebellion (abbreviated as XR) is a UK-headquartered global environmental movement, with the stated aim of using nonviolent civil disobedience to compel government action to avoid tipping points in the climate system, biodiversity loss, and the risk of social and ecological collapse. Extinction Rebellion was established in Stroud in May 2018 by Gail Bradbrook, Simon Bramwell, and Roger Hallam, along with eight other co-founders from the campaign group Rising Up! Its first major action was to occupy the London Greenpeace offices on 17 October 2018, which was followed by the public launch at the "Declaration of Rebellion" on 31 October 2018 outside the UK Parliament.
Mount Wilson ObservatoryThe Mount Wilson Observatory (MWO) is an astronomical observatory in Los Angeles County, California, United States. The MWO is located on Mount Wilson, a peak in the San Gabriel Mountains near Pasadena, northeast of Los Angeles. The observatory contains two historically important telescopes: the Hooker telescope, which was the largest aperture telescope in the world from its completion in 1917 to 1949, and the 60-inch telescope which was the largest operational telescope in the world when it was completed in 1908.
Circumstellar dustCircumstellar dust is cosmic dust around a star. It can be in the form of a spherical shell or a disc, e.g. an accretion disk. Circumstellar dust can be responsible for significant extinction and is usually the source of an infrared excess for stars that have it. For some evolved stars on the asymptotic giant branch, the dust is composed of silicate emissions while others contain the presence of other dust components. According to a study, it is still uncertain whether the dust is a result of crystalline silicate or polycyclic aromatic hydrocarbon.
W. M. Keck ObservatoryThe W. M. Keck Observatory is an astronomical observatory with two telescopes at an elevation of 4,145 meters (13,600 ft) near the summit of Mauna Kea in the U.S. state of Hawaii. Both telescopes have aperture primary mirrors, and when completed in 1993 (Keck 1) and 1996 (Keck 2) were the largest optical reflecting telescopes in the world. They are currently the 3rd and 4th largest. With a concept first proposed in 1977, telescope designers at the University of California, Berkeley (Terry Mast) and Lawrence Berkeley Laboratory (Jerry Nelson) had been developing the technology necessary to build a large, ground-based telescope.
Giovanni Battista RiccioliGiovanni Battista Riccioli, SJ (17 April 1598 – 25 June 1671) was an Italian astronomer and a Catholic priest in the Jesuit order. He is known, among other things, for his experiments with pendulums and with falling bodies, for his discussion of 126 arguments concerning the motion of the Earth, and for introducing the current scheme of lunar nomenclature. He is also widely known for discovering the first double star. He argued that the rotation of the Earth should reveal itself because on a rotating Earth, the ground moves at different speeds at different times.
Telluric contaminationTelluric contamination is contamination of the astronomical spectra by the Earth's atmosphere. Most astronomical observations are conducted by measuring photons (electromagnetic waves) which originate beyond the sky. The molecules in the Earth's atmosphere, however, absorb and emit their own light, especially in the visible and near-IR portion of the spectrum, and any ground-based observation is subject to contamination from these telluric (earth-originating) sources.
MastodonA mastodon (μαστός 'breast' + ὀδούς 'tooth') is any proboscidean belonging to the extinct genus Mammut. Mastodons inhabited North and Central America from the late Miocene up to their extinction at the end of the Pleistocene 10,000 to 11,000 years ago. Mastodons are the most recent members of the family Mammutidae, which diverged from the ancestors of elephants at least 25 million years ago. M. americanum, the American mastodon, and M. pacificus, the Pacific mastodon, are the youngest and best-known species of the genus.
