Halos, Bubbles and Old Explosions

日冕、气泡和远古爆炸

A newly discovered hot halo, a cosmic fountain and ghostly bubbles produced by an ancient explosion could change the way scientists look at galaxies¹, including our own Milky² Way, astronomers⁴ reported today.

今天，有天文学家说，一个新发现的热日冕、一处宇宙源以及某次远古爆炸产生的幽灵般的气泡，可能会改变科学家对包括我们银河系在内星系的认识。

All three findings pointed⁵ to dynamic movement in galaxies and in monstrous⁶ galactic clusters, the largest stable structures in the universe. The discovery should enable astronomers to better identify phenomena⁷ as they look at new galaxies or take a new look at already known ones.

所有的三项发现都指出，在宇宙最大的稳定结构，即星系和巨大银河星团中有动态的运动。这一发现能使天文学家更好地解释他们在观察新星系或已认识星系时看到的现象。

In the case of the Milky Way, astronomers detected a huge, hot gas halo, or corona⁸, that could be as much as 100,000 light-years across, much bigger than earlier scientists theorized. A light-year is about 6 trillion miles, the distance light travels in a year.

以银河系为例，天文学家检测到一个巨大的热气日冕，它横跨10万光年，比先前科学家的理论推测要大许多。一光年大约6百亿亿英里，即光行走一年的距离。

This halo could extend all the way to the Milky Way's nearest neighboring galaxies, the Magellanic Clouds, scientists said.

科学家说，该日冕可能一直延伸到银河系最近的星系麦哲伦云。

Astronomers found the halo using NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite to peer beyond the edges of our home galaxy⁹. Above and below the galactic plain, in which Earth and our solar system reside, they detected an extremely thin, hot gas corona, or halo.

天文学家是使用美国航空航天局的远紫外线光谱探测仪(FUSE)卫星，在我们所居住的星系边缘外发现此日冕的。在这上下居住着地球和我们的太阳系的星系平原上，科学家发现一种极薄的热气日冕。

Invisible to optical devices, the halo can be seen by FUSE as a blue, football-shaped envelope around the galaxy.

光学仪器是看不见这种日冕的，通过FUSE可看到，这种日冕围绕在银河系周围，象一个蓝色足球形状的外壳。

When these clouds fell in, their edges — composed of ionized oxygen — lit up, much as meteors streak¹⁰ across the sky when they enter Earth's atmosphere, said Kenneth Sembach of the Space Telescope Science Institute.

空间望远镜科学研究所的Kenneth Sembach说，当这些云落进去时，它们由离子氧组成的边缘发光，就象流星进入地球大气层时划过天空的光亮。

The halo is thin — perhaps 10 billion billion times less dense¹¹ than air — and hot, possibly 1 million degrees Fahrenheit¹², Sembach told reporters at a meeting of the American Astronomical¹³ Society in Washington.

Sembach在华盛顿美国天文学学会的会议上告诉记者，这种日冕非常薄，大约10万万亿倍小于空气的密度，而且非常热，大约高达华氏1百万度。

"We believe we've found evidence for a very hot halo of extended gas around the Milky Way galaxy," Sembach said. "It's going to help astronomers understand better how galaxies are assembled and hopefully how they evolved over time."

Sembach说："我们相信我们已经发现证据，表明在银河系周围有扩展的高温冕。这将有助于天文学家更好地理解星系是怎样集结和怎样随时间变化的。"?

Because astronomers are still detecting the in-falling clouds, they believe the Milky Way is still pulling in material, even though it is billions of years old.

因为天文学家仍然在监测内落的云，所以他们相信银河系仍然在吸引外部物质，虽然它已存在了数十亿年。

Astronomer³ Edward Murphy of the University of Virginia also used FUSE to discover a possible galactic fountain in a nearby galaxy, formally named NGC 4631 but also known as the Whale because that is what it looks like when viewed from Earth with an optical telescope.

维吉利亚大学的天文学家Edward Murphy也用FUSE发现，在附近的星系可能存在一个星系源，正式命名为NGC4631，但也叫作"鲸"，因为从地球上用光学望远镜观察，它像一头鲸。

However, when Murphy and his colleges examined the Whale with FUSE, they found an area of furious star formation, where extremely hot young stars lived fast and died young in the same clusters where they were born.

然而，当Murphy和他的同事用FUSE观察"鲸"时，他们发现一个狂暴的造星区域，这里的高温新星生命短暂，在它们出生的同一星团中就幼年夭折。

So many of these hot stars exploded as supernovas that the remnants of these blasts overlapped¹⁴ with each other, creating hot bubbles that rose up out of the galactic plain and eventually burst, releasing hot gas into the Whale's galactic halo, Murphy said.

Murphy说，这么多高温新星爆炸为超新星，以至于这些彼此重叠的爆炸残余产生热气泡，这些热气泡在银河系平原外升起，最终导致爆炸，向"鲸"的星系冕释放出热气。