Hubble's Glittering Frisbee Galaxy | A brilhante galáxia de disco

Esta imagem da Câmera 3 de Campo Amplo do Hubble (WFC3) mostra uma seção de NGC 1448, uma galáxia espiral localizada a cerca de 50 milhões de anos-luz da Terra, na pouco conhecida constelação do Horologium (O Relógio de Pêndulo). Nós tendemos a imaginar as galáxias e espirais como sendo massivas, e não corpos celestiais mais ou menos circulares, de forma que esta brilhante oval não parece bem adequada para isso. O que está acontecendo?

Imagine uma galáxia espiral tão circular quanto um disco girando suavemente no espaço. Quando o vemos de frente, nossas observações revelam uma espetacular quantidade de detalhes e estrutura — um grande exemplo do Hubble é a visão do telescópio de Messier 51, também chamada Galáxia do Redemoinho. Entretanto, o disco de NGC 1448 está bem quase de lado em relação à Terra, dando-lhe uma aparência que é mais oval do que circular. Os braços espirais, que se curvam para fora do denso núcleo de NGC 1448, mal podem ser vistos.

Embora galáxias espirais possam parecer estátivas com sua formas pitorescas congeladas no espaço, isso está muito longe de ser verdade. As estrelas nessas densas e emocionantes  configurações espirais estão se movendo constantemente à medida que orbitam ao redor do núcleo galáctico, com aquelas no interior tornando a mais veloz do que aquelas situados mais para fora.

Isso torna a formação e existência contínua dos braços de uma galáxia espiral algo como uma charada cósmica, porque os braços embrulhados ao redor do núcleo giratório dveriam tornar-se mais fortemente enrolados, à medida que o tempo passa — mas não é isso o que se vê. Isso é conhecido como o problema do enrolamento.

Tradução de Luiz Leitão da Cunha

This image from Hubble’s Wide Field Camera 3 (WFC3) shows a section of NGC 1448, a spiral galaxy located about 50 million light-years from Earth in the little-known constellation of Horologium (The Pendulum Clock). We tend to think of spiral galaxies as massive and roughly circular celestial bodies, so this glittering oval does not immediately appear to fit the visual bill. What’s going on?

Imagine a spiral galaxy as a circular frisbee spinning gently in space. When we see it face on, our observations reveal a spectacular amount of detail and structure — a great example from Hubble is the telescope’s view of Messier 51, otherwise known as the Whirlpool Galaxy. However, the NGC 1448 frisbee is very nearly edge-on with respect to Earth, giving it an appearance that is more oval than circular. The spiral arms, which curve out from NGC 1448’s dense core, can just about be seen.

Although spiral galaxies might appear static with their picturesque shapes frozen in space, this is very far from the truth. The stars in these dramatic spiral configurations are constantly moving as they orbit around the galaxy’s core, with those on the inside making the orbit faster than those sitting further out.

This makes the formation and continued existence of a spiral galaxy’s arms something of a cosmic puzzle, because the arms wrapped around the spinning core should become wound tighter and tighter as time goes on — but this is not what we see. This is known as the winding problem.



This image from Hubble’s Wide Field Camera 3 (WFC3) shows a section of NGC 1448, a spiral galaxy located about 50 million light-years from Earth in the little-known constellation of Horologium (The Pendulum Clock). We tend to think of spiral galaxies as massive and roughly circular celestial bodies, so this glittering oval does not immediately appear to fit the visual bill. What’s going on?

Imagine a spiral galaxy as a circular frisbee spinning gently in space. When we see it face on, our observations reveal a spectacular amount of detail and structure — a great example from Hubble is the telescope’s view of Messier 51, otherwise known as the Whirlpool Galaxy. However, the NGC 1448 frisbee is very nearly edge-on with respect to Earth, giving it an appearance that is more oval than circular. The spiral arms, which curve out from NGC 1448’s dense core, can just about be seen.

Although spiral galaxies might appear static with their picturesque shapes frozen in space, this is very far from the truth. The stars in these dramatic spiral configurations are constantly moving as they orbit around the galaxy’s core, with those on the inside making the orbit faster than those sitting further out.

This makes the formation and continued existence of a spiral galaxy’s arms something of a cosmic puzzle, because the arms wrapped around the spinning core should become wound tighter and tighter as time goes on — but this is not what we see. This is known as the winding problem.

This image from Hubble’s Wide Field Camera 3 (WFC3) shows a section of NGC 1448, a spiral galaxy located about 50 million light-years from Earth in the little-known constellation of Horologium (The Pendulum Clock). We tend to think of spiral galaxies as massive and roughly circular celestial bodies, so this glittering oval does not immediately appear to fit the visual bill. What’s going on?

Imagine a spiral galaxy as a circular frisbee spinning gently in space. When we see it face on, our observations reveal a spectacular amount of detail and structure — a great example from Hubble is the telescope’s view of Messier 51, otherwise known as the Whirlpool Galaxy. However, the NGC 1448 frisbee is very nearly edge-on with respect to Earth, giving it an appearance that is more oval than circular. The spiral arms, which curve out from NGC 1448’s dense core, can just about be seen.

Although spiral galaxies might appear static with their picturesque shapes frozen in space, this is very far from the truth. The stars in these dramatic spiral configurations are constantly moving as they orbit around the galaxy’s core, with those on the inside making the orbit faster than those sitting further out.

This makes the formation and continued existence of a spiral galaxy’s arms something of a cosmic puzzle, because the arms wrapped around the spinning core should become wound tighter and tighter as time goes on — but this is not what we see. This is known as the winding problem.