The danger of living close to a black hole 與黑洞比鄰而居的危險(xiǎn)

張麗

黑洞是存在于宇宙空間中的一種天體。黑洞的引力極其強(qiáng)大，任何物質(zhì)和輻射都會(huì)被吸入其中，連光線也無法逃脫。故而，“黑洞是時(shí)空曲率大到連光都無法從其事件視界逃脫的天體”。

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（吸積盤）， 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.

[閱讀檢測(cè)]

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

[語言學(xué)習(xí)]

難句分析

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. 這種藍(lán)移的光線也會(huì)使這個(gè)星球變得更熱，這有助于提供液態(tài)而非冷凍水存在的溫度，而液態(tài)水是生命存在的基本條件之一。

【點(diǎn)石成金】本句是一個(gè)復(fù)合句。The blue?shifting...hotter是主句，helping...water作狀語，which引導(dǎo)非限制性定語從句。

背景知識(shí)

藍(lán)移（blue shift）

藍(lán)移，與紅移相對(duì)，也稱藍(lán)位移。在光化學(xué)中，藍(lán)移也指淺色效應(yīng)。藍(lán)移指一個(gè)正向觀察者移動(dòng)的物體所散射的電磁波（比如光）的頻率在光譜線上向藍(lán)端的方向移動(dòng)（意味著波長(zhǎng)縮減）。在互相移動(dòng)的參考系之間的波長(zhǎng)移動(dòng)又叫作多普勒位移或者多普勒效應(yīng)。1993 年，美國(guó)貝爾實(shí)驗(yàn)室在硒化鎘中發(fā)現(xiàn)隨著粒子尺寸的減小，光顏色從紅變成綠進(jìn)而藍(lán)，有人把這種光顏色從紅變成綠進(jìn)而藍(lán)的現(xiàn)象稱為 “藍(lán)移”。