Anders Wegge Keller <wegge@wegge.dk> wrote:
> per@RQNNE.invalid (Per Rønne) writes:
>
> > Anders Wegge Keller <wegge@wegge.dk> wrote:
>
> >> <
http://news.bbc.co.uk/2/hi/sci/tech/specials/washington_2000/649913.stm>
>
> > Der tror jeg nu ikke at der er udbredt enighed om, og Solen bliver
> > først en nova langt længere ud i fremtiden.
>
> Tro hvad du vil. Men lad være med at diskutere det med en astrofysiker,
> hvis du har det så skidt med at blive korrigeret, som du plejer at give
> udtryk for her.
Er du da astrofysiker?
Du har et knap 10 år gammelt link til BBC; du kunne lige så godt have
haft et link til DR.
Og lad os så se hvd artiklen siger:
> By BBC News Online's Damian Carrington in Washington DC
>
> The Earth is entering the final 10% of its lifespan, according to a US
> geoscientist.
I følge en enkelt 'geoscientist', altså mere eller mindre en geolog.
Oxford American English Dictionary:
geoscience
noun (also geosciences)
earth sciences, esp. geology.
DERIVATIVES
geoscientist noun
==
> AAAS Expo Professor James Kasting, at Pennsylvania State University,
> calculates that the Earth's oceans will disappear in about one billion
> years' time, due to increased temperatures from a brightening Sun.
>
> However, well before the planet is left as an arid desert, the level of
> carbon dioxide in the atmosphere will be too low to support plant life,
> destroying the foundation of the food chains.
>
> "The Sun, like all main sequence stars, is getting brighter with time and
> eventually temperatures will become high enough so that the oceans
> evaporate," said Professor Kasting.
>
> At 60 degrees Celsius (140 degrees Fahrenheit), water becomes a major
> constituent of the atmosphere. Much of this water drifts up to the
> stratosphere and is lost into space. Eventually, all the oceans will leak
> out of the Earth's grasp.
>
> Burnt-out planet
>
> "Astronomers always knew that the oceans would evaporate, but they
> typically thought it would occur only when the Sun left the main sequence
> - that will be in five billion years." Sun The Sun will consume Mercury
> Stars leave the main sequence when they stop burning hydrogen. The Sun
> will then become a red giant, swamping and obliterating Mercury. Venus
> will lose its atmosphere and become a burnt-out planet.
Ja, her tales om fem milliarder år.
> "However, my calculations show the oceans may evaporate much earlier,"
> said Professor Kasting. "They are somewhat pessimistic and present a
> worst-case scenario, but they say a billion years."
Ja, hans beregninger - som han selv omtaler som 'pessimistiske' og et
'værste tilfælde scenario' ...
> The earlier loss of carbon dioxide will occur because as the climate gets
> hotter and wetter, more rock is weathered by rain. This dissolves carbon
> dioxide and hides it away on the ocean floor as calcium carbonate.
>
> "Obviously, a billion, even a half billion years, is a long way off in the
> future," said Professor Kasting. "But these models can help us refine our
> understanding of the time that a planet remains in an orbit where life can
> exist."
>
> "If we calculated correctly, Earth has been habitable for 4.5 billion
> years and only has a half billion years left."
Ja, hvis. Jeg ser ingen consensus i den videnskabelige verden i dette
spørgsmål.
> Professor Kasting's comments were made at the annual meeting of the
> American Association for the Advancement of Science.
>
--
Per Erik Rønne
http://www.RQNNE.dk
Errare humanum est, sed in errore perseverare turpe est