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Glossary term: Planeta

Description: Um planeta é definido pela União Astronômica Internacional como um corpo celeste em órbita ao redor de uma estrela ou do remanescente de uma estrela, que é grande o suficiente para ter uma forma quase redonda devido à sua própria força gravitacional, mas não é maciço o suficiente para que ocorra fusão termonuclear em seu núcleo. Ele também deve ser grande o suficiente para que sua gravidade remova outros objetos que passem perto de sua órbita ao redor da estrela. Portanto, são corpos frios (em comparação com as estrelas) que brilham na faixa visível apenas pela luz refletida de suas estrelas, mas emitem luz em comprimentos de onda infravermelhos. Em nosso Sistema Solar, oito planetas orbitam ao redor do Sol. Os planetas podem ser basicamente objetos rochosos, como os planetas internos - Mercúrio, Vênus, Terra e Marte - ou principalmente líquidos e gasosos com um pequeno núcleo sólido, como os planetas externos - Júpiter, Saturno, Urano e Netuno. Os planetas fora do Sistema Solar são chamados de planetas extrassolares ou exoplanetas.

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Term and definition status: The original definition of this term in English have been approved by a research astronomer and a teacher
The translation of this term and its definition is still awaiting approval

The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".

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The planet Jupiter with the two of the four Galilean moons (visible as bright dots) orbiting it.

Jupiter's Rotation, by Vishal Sharma, India

Caption: Third place in the 2021 IAU OAE Astrophotography Contest, category Galilean moons: Jupiter’s Rotation, by Vishal Sharma, India. This time-lapse beautifully shows the rotation of Jupiter and the passage of two Galilean moons on the right side of the frame. Jupiter completes one rotation in just under 10 hours and we see as the Great Red Spot makes its way from left to right. The two moons travel a noticeable fraction of their orbit in this short time. This image was taken in 2020 in the North of India.
Credit: Vishal Sharma/IAU OAE

License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons


The planet Jupiter, seen here as a bright disk, is orbited by the four Galilean moons, seen here as bright dots

Jupiter Moons Movie2, by Nicolas Hurez, Paul-Antoine Matrangolo, and Carl Pennypacker, United States of America

Caption: Second place in the 2021 IAU OAE Astrophotography Contest, category Galilean moons. This sequence shows the orbit of the four Galilean moons around the planet Jupiter. Almost two entire orbits of the innermost moon, Io, can be seen, with the other moons (Europa and Ganymede, but in particular Callisto) being further away, orbiting noticeably slower. The images were obtained in 2018 with the Las Cumbres Global Observatory at different locations on Earth, allowing a continuous sequence of images over approximately half a week without gaps during the day. With clear skies and over the course of several nights, the motion of the Galilean moons can also be observed with binoculars (ideally steady your elbows on a surface).
Credit: Nicolas Hurez, Paul-Antoine Matrangolo and Carl Pennypacker/IAU OAE

License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons


Jupiter with coloured horizontal bands of clouds. The shadow of the moon Io is seen as a dark circle in the top left

Jupiter, Io and its shadow, by Ralf Burkart, Germany

Caption: First place in the 2021 IAU OAE Astrophotography Contest, category Galilean moons. This time-lapse of Jupiter taken in 2017 from Germany beautifully illustrates the transit of one of the Galilean moons, Io, in front of Jupiter. As this is simply a moon casting a shadow on a planet it is equivalent to a lunar eclipse on Earth observed from further away. While the shadow of the moon is clearly visible from the beginning, it might be difficult to spot the moon itself against the background of the beautiful atmospheric bands of Jupiter the first time the video is seen. Watching it repeatedly allows appreciating the rapid motion and rotation in this fantastic observation.
Credit: Ralf Burkart/IAU OAE

License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons


O planeta Mercúrio coberto por muitas crateras

Mercúrio

Caption: Esta imagem é uma composição de um mosaico de fotos da superfície do planeta Mercúrio obtidas pela sonda espacial MESSENGER (Mercury Surface, Space Environment, Geochemistry and Ranging). A MESSENGER foi lançada pela NASA em 2004 e explorou Mercúrio de 2011 a 2015.
Credit: NASA/Laboratório de Física Aplicada da Universidade Johns Hopkins/Instituição Carnegie de Washington credit link

License: PD Public Domain icons


O planeta Vênus mostrando nuvens brancas envolvendo o planeta

Vênus em luz visível

Caption: Esta foto, tirada pela sonda Mariner 10 da NASA, mostra como o planeta Vênus aparece a olho nu. Vênus está envolto em uma espessa atmosfera de nuvens, dominada por dióxido de carbono, que nunca revela sua superfície quente.
Credit: NASA/JPL-Caltech credit link

License: PD Public Domain icons

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Design Your Alien

Design Your Alien

astroEDU educational activity (links to astroEDU website)
Description: Design an alien life form suited for an extra-terrestrial world.

License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons
Tags: Life , Environment , Extra-terrestrial , Art , Creativity , Hands-on , Alien
Age Ranges: 8-10 , 10-12
Education Level: Primary , Secondary


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