Page 75 - Full Solutions 2nd Advanced Student Book_Neat

T*me trare[
ffi"ffi}fl:*Tfiffi Worl< in pairs. Answer the questions.
1 Do you l<now any stories or films in which the characters for bqinnerc
travel through time? e
2 Do you thinl< it will ever be possible to travel through I t I I Just over 100 years ago, in 1895, H. G. We[[s's
classic story The Time Machine was first pubiished. As befits
time? Why?/Why not?
the subject matter, that was the'minus tenth'anniversary
Read the text. Which sentence best sums up the opinion of of the first pubtication, in 1905, of Atbert Einstein's special
the writer? 5 theory of retativity. lt was Einstein, as every schoolchitd
knows, who first described time as 'the fourth dimension'
1 Time travel runs counter to common sense and must
- and every schootchjtd is wrong. As a matter of fact it
therefore be im possibte.
2 Time travel may one day be possible because the laws of was We[[s who wrote in The Time Mochine that'there is no
difference between Time and any of the three dimensions of
science do not rule it out.
ro Space, except that our consciousness moves atong itJ
3 Time traveI is impossible because of the inherent
B Ever since then, writers have been fascinated by
paradoxes. I I I
tirne traveL, and especia[ty by the paradoxes that seem
-
3 Match headings 1-6 with paragraphs A-F. to confront any genuine time travetler (something that
1 The impossibitity of time traveI We[[s neglected to investigate). The ctassic example is
2 Limitations ir the so-calted 'granny paradox', where a time trave[ter
3 Can we trust our common sense? inadvertently causes the death of his granny when she was
4 Versions of reatity a Littte girt, so that the travetler's mother, and therefore
5 A schootboy error the travetter himsetf, were never born. In which case, he
6 A writer comes to the aid of the scientists did not go back in time to kitt his relative, and so on.
zo A less gruesome exampte was entertaining[y provided by
the science-fiction writer Robert Heintein in his story By
His Bootstrops. The protagonist stumbles across a time-
travel device brought back to the present by a visitor from
the distant future. He steals the device and traveis forward
zs in tjme. He constantly worries about being found by the
old man from whom he stole the time machine - untiI one
day. many years later, he realises that he himsetfis now
the otd man, and carefu[[y arranges for his younger se[f to
'find' and 'steat' the time machine.
i_
| |
30 C | As these paradoxes show us, the possibility of our
being abte to traveI through time is ctearly irrationaI and
runs counter to common sense. The prob[em is that
common sense is not always the most reliabte means
of assessing scientific theories. To take Einstein's own
:s theories again, it is hardty common sense that objects
get both heavier and shorter the faster they move. or that
moving ctocks run stow. Yet both of these predictions
of retativity theory have been borne out many times in
experiments. In fact, when you look close[y at the generaI
+o theory of reLativity - the best theory of time and space we
have - it turns out that there is nothing in it to rute out
the possibility of time travel. The theory impLies that time
gAye!-qray be exceedingly difficutt, but not impossibte.
-
---T----T Perhaps inevitabty, it was through science fiction
Lql I
,, I-hat
serjous scientists finatly convinced themselves
that time travel could be made to work by a sufficientty
advanced civitisation. What happened was this. Car[
Sagan, a weL[-known astronomer, had written a noveI in
which his characters trave[[ed through a btack ho[e from
ro a point near the Earth to a point near the star Vega.

74 Unit 7 .,, Journeys