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The Twin Paradox

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Exoplanets and 2019 Physics Nobel Prize

   In 2019 the Nobel Prize in Physics has been awarded to Michel Mayor and Didier Queloz for the discovery of the first exoplanet around a Sun-like star. I would like to point out that the planet has not been discovered in 2019 or any year near that. 51 Pegasi b, was the first exoplanet ever found around a Sun-type star, is discovery was announced on 6 October 1995 by Mayor and Queloz, who detected it using the ELODIE spectrograph at the Observatoire de Haute-Provence in France. This discovery revolutionised astronomy, initiating an entirely new field and new instruments focused on finding and characterising exoplanets.         Figure 1:  Didier Queloz and Michel Mayor at La Silla Introduction     Exoplanets or extrasolar planets, are planets outside the Solar System. From 1917 until 8 February 2021, has been discovered a total of 4,352 exoplanets in 3,257 systems, with 722 systems hosting more than one planet.     You might ask, how do we know that planets are there? How he can detec

Vida em Vénus? Astrónomos encontram fosfina nas nuvens de Vénus.

      Na passada segunda-feira, pesquisadores da Universidade de Cardiff, no Reino Unido, juntamente com o Instituto de Tecnologia de Massachusetts, nos Estados Unidos, anunciaram a descoberta de fosfina na atmosfera de Vénus.  Fotografia tirada pela sonda Mariner 10  em 1974 .    Vénus, assim chamado em homenagem à deusa romana do amor e da beleza é um planeta coberto por densas nuvens compostas de dióxido de carbono e uma pequena quantidade de nitrogénio, e umas ‘gotas’ de ácido sulfúrico. A temperatura média no planeta é de 461℃, o que torna a superfície venusiana mais quente que a de Mercúrio, que atinge um máximo de 420℃ na sua superfície. Devido a estes motivos, poucos se tem focado no planeta como possível hospedeiro de vida. Em vez disso, cientistas têm-se focado em Marte e mais recentemente na lua de Saturno, Europa Enceladus e outras luas geladas dos planetas gigantes.    A fosfina (H 3 P) , ou fosfano, é um gás à temperatura ambiente, incolor, inflamável e tóxico, cujo po

Chemical Composition of Orion Nebula

O rion Nebula (Figure 1), also known as Messier 42 1 (or just M42, and also NGC 1976), is a diffuse nebula 2 situated in the Milky Way, roughly at 1,500 light years from us (planet Earth), being the closest region of massive star formation. According to data collected by astronomers the Nebula has a mass 2,000 times greater than the Sun and is 24 light-years across. The Orion Nebula is easily detected in the night sky with the naked eye (in an environment with low light pollution), being south of Orion’s Belt 3 . The Orion Nebula has been the most observed H II   region due to 3 factors: its apparent size, low reddening and high emission measure. The main goal of this article is to give a chemical perspective of the M42. This cloud of gas is being heated by the intense radiation of the Trapezium stars 4 embedded within it. Figure  1 : Image taken by SAC (Section of Astronomy, Astrophysics and  Aeronautics of Academic Section of Coimbra) 1- From the Messier catalogue;