Glossary term: Galáxia
Description: Uma galáxia é um sistema de estrelas e outros componentes materiais, como matéria escura, gás e poeira, que está gravitacionalmente ligado e geralmente separado de seus vizinhos por centenas de milhares de anos-luz. As galáxias têm várias formas e tamanhos diferentes. As menores galáxias podem ter alguns milhares de estrelas, enquanto as maiores podem ter dezenas de trilhões. "A Galáxia" ou "Galáxia" com letra maiúscula geralmente se refere à nossa galáxia natal, a Via Láctea, que tem cerca de 100 a 400 bilhões de estrelas.
Related Terms:
- Dark Matter
- Disco Galaxy
- Poeira
- Galáxia anã
- Galáxia Elíptica
- Bojo Galáctico
- Centro Galáctico
- Disco Galáctico
- Halo Galáctico
- Aglomerado de galáxias
- Gás
- Greenwich Mean Time Zone (GMT)
- Galáxia Irregular
- Milky Way
- Galáxia espiral
- Estrela
- Barra Galáctica
- Galáxia Lenticular
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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".
If you notice a factual or translation error in this glossary term or definition then please get in touch.
Related Media
Hubble Ultra Deep Field
Caption: This awe-inspiring image referred to as the Hubble Ultra-Deep Field (HUDF), was obtained using the Hubble Space Telescope (HST), by combining 800 exposures from 400 orbits of the HST, which equates to 11.3 days of total exposure time.
The image shows nearly 10,000 galaxies and was taken in the direction of a patch of sky with the least amount of stars from the Milky Way galaxy in the field of view. The region of sky that the HST observed corresponds to 1/10 the angular size of the Full Moon, which is roughly equal to approximately a 1 millimeter-sized object placed 1 meter away.
Every object in the image, except for the bright points with the crosshairs, are galaxies. As a consequence of the speed of light being a constant in a vacuum, the more distant an object, the further back in time we are observing. Therefore, the light from some of the galaxies in the HUDF image is from when the Universe as only a few hundred million years old. The HUDF image takes us through on a journey through space, and also in time.
Credit: NASA, ESA, and S. Beckwith (STScI) and the HUDF Team
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License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons
Fusão de galáxias espirais
Caption: Esta imagem mostra duas galáxias espirais em interação, localizadas a aproximadamente 150 milhões de anos-luz de distância. As duas galáxias espirais estão envolvidas nesta dança, criando distorções visíveis em seus braços espirais devido à atração gravitacional. O que começa como um abraço nesta imagem terminará na fusão dessas duas galáxias em uma única galáxia, provavelmente elíptica.
Credit: ESO
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License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons
Galáxia do Sombrero
Caption: Esta proeminente galáxia M 104 é frequentemente chamada de galáxia Sombrero devido à sua semelhança com o chapéu mexicano. Este aspecto é criado pelo disco fino visto quase de perfil, que parece iluminado pelo bojo dominante. Tanto o disco quanto o bojo possuem estrelas, mas as estrelas do bojo tendem a ser mais antigas, enquanto o disco também abriga grandes quantidades de poeira e gás, criando regiões sobreadas. A M 104 está localizada na constelação de Virgem, a aproximadamente 50 anos-luz de distância. Embora alguns dos pontos visíveis na imagem sejam estrelas em primeiro plano e outros galáxias ao fundo, a maioria são, na verdade, aglomerados globulares, aglomerados densos e massivos de estrelas, associados à Galáxia Sombrero.
Credit: ESO/P. Barthel
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License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons
A Galáxia Lenticular NGC 2787
Caption: A galáxia lenticular NGC 2787. Esta galáxia é uma galáxia em disco, mas não possui a estrutura grande e dominante dos braços espirais observada nos discos das galáxias espirais. Seu núcleo é muito brilhante em comparação com o núcleo de uma galáxia espiral. Anéis finos de poeira podem ser vistos no disco da galáxia.
Credit: NASA/ESA e a Equipe do Hubble Heritage
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License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons
Related Diagrams
Leo Constellation Map
Caption: The zodiac constellation Leo and its surrounding constellations. Starting from the top of the diagram and going clockwise, these are Leo Minor, Cancer, Sextans, Hydra, Crater, Virgo and Ursa Major. The brightest star in Leo, Regulus, lies almost exactly on the ecliptic (shown here as a blue line): the path the Sun appears to take across the sky over the course of a year. The Sun spends the period from mid August to mid September in Leo. The other planets in the Solar System can often be found in Leo.
Leo spans the celestial equator and is thus part of it is visible at some time in the year from all of planet Earth with some of the constellation obscured for the most arctic and antarctic regions of the world. Leo is most visible in the evenings in the northern hemisphere spring and southern hemisphere autumn.
Several objects can be seen in Leo, including M65 and M66 – two galaxies in the Leo Triplet, a trio of galaxies including NGC 3628, not listed here. In addition, M96, a spiral galaxy, can be seen as a fuzzy object using a small telescope, and Messier 105, an elliptical galaxy. Each of these objects are labelled on the map as red ellipses.
The y-axis of this diagram is in degrees of declination with north as up and the x-axis is in hours of right ascension with east to the left. The sizes of the stars marked here relate to the star's apparent magnitude, a measure of its apparent brightness. The larger dots represent brighter stars. The Greek letters mark the brightest stars in the constellation. These are ranked by brightness with the brightest star being labelled alpha, the second brightest beta, etc., although this ordering is not always followed exactly. The dotted boundary lines mark the IAU's boundaries of the constellations and the solid green lines mark one of the common forms used to represent the figures of the constellations. Neither the constellation boundaries, nor the line marking the ecliptic, nor the lines joining the stars appear on the sky.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope
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Related Activities
Glitter Your Milky Way
astroEDU educational activity (links to astroEDU website) Description: Explore the Milky Way and characteristics of galaxies using glitter drawing.
License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons
Tags:
Art
, Creativity
, Hands-on
, Handcraft
Age Ranges:
6-8
, 8-10
Education Level:
Middle School
, Primary
Areas of Learning:
Fine Art focussed
Costs:
Medium Cost
Group Size:
Group
Skills:
Communicating information
Coma Cluster of Galaxies
astroEDU educational activity (links to astroEDU website) Description: The basics of galaxy classification, using Hubble Space Telescope images.
License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons
Tags:
Coma Cluster
Age Ranges:
14-16
, 16-19
, 19+
Education Level:
Secondary
, University
Areas of Learning:
Guided-discovery learning
Costs:
Low Cost
Duration:
1 hour
Group Size:
Group
Skills:
Analysing and interpreting data
, Communicating information
, Constructing explanations
, Planning and carrying out investigations
Living in the Milky Way
astroEDU educational activity (links to astroEDU website) Description: Build a model of the Milky Way to discover what our galaxy contains.
License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons
Tags:
Hands-on
, Model
Age Ranges:
6-8
, 8-10
Education Level:
Primary
Areas of Learning:
Problem-solving
, Social Research
Costs:
Medium Cost
Duration:
1 hour 30 mins
Group Size:
Group
Skills:
Asking questions
, Communicating information
, Developing and using models
3D Universe: the Milky Way and friends
astroEDU educational activity (links to astroEDU website) Description: Use tactile models printed in 3D to explore our galactic neighborhood.
License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons
Age Ranges:
10-12
, 12-14
, 14-16
, 16-19
, 19+
Education Level:
Middle School
, Secondary
, University
Areas of Learning:
Guided-discovery learning
, Interactive Lecture
, Modelling
Costs:
Medium Cost
Duration:
1 hour
Group Size:
Group
Skills:
Analysing and interpreting data
, Developing and using models
