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Impact Events
An impact event is a collision between astronomical objects causing measurable effects. Impact events have physical consequences and have been found to regularly occur in planetary systems, though the most frequent involve asteroids, comets or meteoroids and have minimal effect. When large objects impact terrestrial planets such as the Earth, there can be significant physical and biospheric consequences, though atmospheres mitigate many surface impacts through atmospheric entry. Impact craters and structures are dominant landforms on many of the Solar System's solid objects and present the strongest empirical evidence for their frequency and scale. Impact events appear to have played a significant role in the evolution of the Solar System since its formation. Major impact events have significantly shaped Earth's history, and have been implicated in the formation of the Earth–Moon system. Impact events also appear to have played a significant role in the evolutionary history of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Impact Event
An impact event is a collision between astronomical objects causing measurable effects. Impact events have physical consequences and have been found to regularly occur in planetary systems, though the most frequent involve asteroids, comets or meteoroids and have minimal effect. When large objects impact terrestrial planets such as the Earth, there can be significant physical and biospheric consequences, though atmospheres mitigate many surface impacts through atmospheric entry. Impact craters and Impact structure, structures are dominant landforms on many of the Solar System's solid objects and present the strongest empirical evidence for their frequency and scale. Impact events appear to have played a significant role in the Formation and evolution of the Solar System, evolution of the Solar System since its formation. Major impact events have significantly shaped History of the Earth, Earth's history, and have been implicated in the giant impact theory, formation of the Earth†... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Panspermia
Panspermia () is the hypothesis, first proposed in the 5th century BCE by the Greek philosopher Anaxagoras, that life exists throughout the Universe, distributed by space dust, meteoroids, asteroids, comets, and planetoids, as well as by spacecraft carrying unintended contamination by microorganisms.Forward planetary contamination like '' Tersicoccus phoenicis'', that has shown resistance to methods usually used in spacecraft assembly clean rooms: Panspermia is a fringe theory with little support amongst mainstream scientists. Critics argue that it does not answer the question of the origin of life but merely places it on another celestial body. It is also criticized because it cannot be tested experimentally. Panspermia proposes (for example) that microscopic lifeforms which can survive the effects of space (such as extremophiles) can become trapped in debris ejected into space after collisions between planets and small Solar System bodies that harbor life. Panspermia studies c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spitzer Space Telescope
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, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 2547
NGC 2547 is a southern open cluster in Vela, discovered by Nicolas Louis de Lacaille in 1751 from South Africa. The star cluster is young with an age of 20-30 million years. Observations with the Spitzer Space Telescope showed a shell around the B3 III/IV-type star HD 68478. This could be a sign of recent mass loss in this star. A study using Gaia DR2 data showed that NGC 2547 formed about 30 million years ago together with a new discovered star cluster, called BJ20186. The star cluster NGC 2547 has a similar age compared with Trumpler 10, NGC 2451B, Collinder 135 and Collinder 140. It was suggested that all these clusters formed in a single event of triggered star formation. NGC 2547 shows evidence for mass segregation down to 3 . Cluster members with debris disks Observations with the Spitzer Space Telescope have shown that ≤1% of the stars in NGC 2547 have infrared excess in 8.0 μm and 30-45% of the B- to F-type stars have infrared excess at 24 μm. The system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
