The Spitzer Space Telescope, formerly the Space Infrared Telescope Facility (SIRTF), was an infrared space telescope launched in 2003. Operations ended on 30 January 2020. Spitzer was the third space telescope dedicated to infrared astronomy, following IRAS (1983) and ISO (1995–1998). It was the first spacecraft to use an Earth-trailing orbit, later used by the Kepler planet-finder. The planned mission period was to be 2.5 years with a pre-launch expectation that the mission could extend to five or slightly more years until the onboard liquid helium supply was exhausted. This occurred on 15 May 2009. Without liquid helium to cool the telescope to the very low temperatures needed to operate, most of the instruments were no longer usable. However, the two shortest-wavelength modules of the IRAC camera continued to operate with the same sensitivity as before the helium was exhausted, and continued to be used into early 2020 in the Spitzer Warm Mission.During the warm mission, the two short wavelength channels of IRAC operated at 28.7 K and were predicted to experience little to no degradation at this temperature...

The Spitzer Space Telescope, formerly the Space Infrared Telescope Facility (SIRTF), was an infrared space telescope launched in 2003. Operations ended on 30 January 2020. Spitzer was the third space telescope dedicated to infrared astronomy, following IRAS (1983) and ISO (1995–1998). It was the first spacecraft to use an Earth-trailing orbit, later used by the Kepler planet-finder. The planned mission period was to be 2.5 years with a pre-launch expectation that the mission could extend to five or slightly more years until the onboard liquid helium supply was exhausted. This occurred on 15 May 2009. Without liquid helium to cool the telescope to the very low temperatures needed to operate, most of the instruments were no longer usable. However, the two shortest-wavelength modules of the IRAC camera continued to operate with the same sensitivity as before the helium was exhausted, and continued to be used into early 2020 in the Spitzer Warm Mission.During the warm mission, the two short wavelength channels of IRAC operated at 28.7 K and were predicted to experience little to no degradation at this temperature...

The Spitzer Space Telescope, formerly the Space Infrared Telescope Facility (SIRTF), was an infrared space telescope launched in 2003. Operations ended on 30 January 2020. Spitzer was the third space telescope dedicated to infrared astronomy, following IRAS (1983) and ISO (1995–1998). It was the first spacecraft to use an Earth-trailing orbit, later used by the Kepler planet-finder. The planned mission period was to be 2.5 years with a pre-launch expectation that the mission could extend to five or slightly more years until the onboard liquid helium supply was exhausted. This occurred on 15 May 2009. Without liquid helium to cool the telescope to the very low temperatures needed to operate, most of the instruments were no longer usable. However, the two shortest-wavelength modules of the IRAC camera continued to operate with the same sensitivity as before the helium was exhausted, and continued to be used into early 2020 in the Spitzer Warm Mission.During the warm mission, the two short wavelength channels of IRAC operated at 28.7 K and were predicted to experience little to no degradation at this temperature...

Falafel (; Arabic: فلافل, [fæˈlæːfɪl] (listen)) is a deep-fried ball or patty-shaped fritter of Arab origin, featuring in Middle Eastern cuisine (especially in Egyptian and Levantine cuisines) made from broad beans, ground chickpeas, or both. Falafel is often served in a pita, samoon, or wrapped in a flatbread known as taboon; "falafel" also frequently refers to a wrapped sandwich that is prepared in this way. The falafel balls may be topped with salads, pickled vegetables, and hot sauce, and drizzled with tahini-based sauces. Falafel balls may also be eaten alone as a snack or served as part of a meze tray (assortment of appetizers). Falafel is eaten throughout the Middle East, and is a common street food. Falafel is usually made with fava beans in Egyptian cuisine, where it most likely originated, with chickpeas in Palestinian cuisine, or either just...

The Natural History and Antiquities of Selborne, or just The Natural History of Selborne is a book by English parson-naturalist Gilbert White (1720–1793). It was first published in 1789 by his brother Benjamin. It has been continuously in print since then, with nearly 300 editions up to 2007.The book was published late in White's life, compiled from a mixture of his letters to other naturalists—Thomas Pennant and Daines Barrington; a 'Naturalist's Calendar' (in the second edition) comparing phenology observations made by White and William Markwick of the first appearances in the year of different animals and plants; and observations of natural history organized more or less systematically by species and group. A second volume, less often reprinted, covered the antiquities of Selborne. Some of the letters were never posted, and were written for the book. White's Natural History was at once well received by contemporary critics and the public, and continued to be admired by a diverse range of nineteenth and twentieth century literary figures. His work has been seen as an early...