张丽

黑洞是存在于宇宙空间中的一种天体。黑洞的引力极其强大，任何物质和辐射都会被吸入其中，连光线也无法逃脱。故而，“黑洞是时空曲率大到连光都无法从其事件视界逃脱的天体”。

Could life exist on a planet orbiting a supermassive black hole？ And if so， what would existence on such a planet be like？ In fact， there is some danger if you live close to a black hole.

Time slows down

According to the ground?breaking sci?fi movie Interstellar， whose scientific advisor was the Nobel Prize?winning physicist Kip Thorne， the space?time surrounding such a planet would be warped in line with Einsteins theory of general relativity. Consequently， time would pass at a slowed?down rate for those on the planet compared to elsewhere in the universe.

Blueshifted light

Any planet around a black hole would have to receive its light from a source other than a star. Instead， the planet would likely be bathed in light emanating from the black holes accretion disks（吸积盘）， or hot halos of gas and matter that collect around and fall into such supermassive objects in space. This blue?shifting of light would also make the planet hotter， helping to provide the sort of temperatures that would allow for the presence of liquid and not frozen water， which is one of the fundamental conditions necessary for life.

High radiation from UV light， X?rays & neutrinos

Furthermore， there are a number of other factors that would ultimately make the possibility of a habitable planet near to a supermassive black hole even less likely. For instance， supermassive black holes are generally found at the center of galaxies， where the density of stars is extremely high. A planet circling the supermassive black hole at the center of our galaxy would have a night sky at least 100，000 times brighter than on Earth， meaning you could read at night without the use of electricity. It would also result in significantly higher amounts of background UV light and X?rays， which would produce strong harmful radiation to living creatures.

A planet orbiting a supermassive black hole would not be very helpful to the development of complex life and the possibility of life surviving on such a planet is ultimately pretty unlikely indeed.

[阅读检测]

1. Whats the main function of the first paragraph？

A. To ask for some debates.

B. To give an explanation.

C. To give readers a warning.

D. To lead in the topic of the text.

2. Which of the following can replace the underlined word “emanating” in paragraph 3？

A. Gathering. B. Producing.

C. Analyzing. D. Expecting.

3. Living creatures are in danger on a planet

circling a black hole          .

A. because of general relativity

B. because of lack of brightness

C. because of strong harmful radiation

D. because of slow development of complex life

[语言学习]

难句分析

This blue?shifting of light would also make the planet hotter， helping to provide the sort of temperatures that would allow for the presence of liquid and not frozen water， which is one of the fundamental conditions necessary for life. 这种蓝移的光线也会使这个星球变得更热，这有助于提供液态而非冷冻水存在的温度，而液态水是生命存在的基本条件之一。

【点石成金】本句是一个复合句。The blue?shifting...hotter是主句，helping...water作状语，which引导非限制性定语从句。

背景知识

蓝移（blue shift）

蓝移，与红移相对，也称蓝位移。在光化学中，蓝移也指浅色效应。蓝移指一个正向观察者移动的物体所散射的电磁波（比如光）的频率在光谱线上向蓝端的方向移动（意味着波长缩减）。在互相移动的参考系之间的波长移动又叫作多普勒位移或者多普勒效应。1993 年，美国贝尔实验室在硒化镉中发现随着粒子尺寸的减小，光颜色从红变成绿进而蓝，有人把这种光颜色从红变成绿进而蓝的现象稱为 “蓝移”。