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Telescopes 'worthless' by 2050


Grant
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http://news.bbc.co.uk/1/hi/sci/tech/4755996.stm

Ground-based astronomy could be impossible in 40 years because of pollution from aircraft exhaust trails and climate change, an expert says.

Aircraft condensation trails - known as contrails - can dissipate, becoming indistinguishable from other clouds.

If trends in cheap air travel continue, says Professor Gerry Gilmore, the era of ground astronomy may come to an end much earlier than most had predicted.

Aircraft along with climate change will contribute to increased cloud cover.

You either give up your cheap trips to Majorca, or you give up astronomy. You can't do both

Gerry Gilmore, University of Cambridge

The timescale is based on extrapolating air traffic growth figures. The BBC has learned that the calculations were made as part of preparations for an upcoming observatory project called the Extremely Large Telescope (ELT).

The ELT is intended to probe planets around nearby stars and look for extremely faint objects in the Universe.

Vision impaired

"It is already clear that the lifetime of large ground-based telescopes is finite and is set by global warming," Professor Gilmore, from Cambridge's Institute of Astronomy, told reporters recently in London.

"There are two factors. Climate change is increasing the amount of cloud cover globally. The second factor is cheap air travel.

"You get these contrails from the jets. The rate at which they're expanding in terms of their fractional cover of the stratosphere is so large that if predictions are right, in 40 years it won't be worth having telescopes on Earth anymore - it's that soon.

"You either give up your cheap trips to Majorca, or you give up astronomy. You can't do both."

Climate change is also expected to increase the amount of water vapour in the atmosphere through evaporation, contributing to overall cloudiness. The increase in cloud cover would affect both optical and infrared astronomy, which would have to be carried out from space.

Radio astronomy would continue to be ground-based.

Identical appearance

Contrails often present little more than a transient nuisance to astronomers; but when certain weather conditions prevail, they can break to look like natural clouds.

Holger Pederson, an astronomer at the Nils Bohr Institute in Copenhagen, Denmark, who has studied contrails, explained: "You can recognise the jet contrails when they are young. So you can stop your observation and then restart as soon as the contrail has passed the field of view of the telescope.

Satellite imagery can be used to monitor contrail evolution

In pictures

"Worse is when the contrails last for hours. Then they degrade into something you can hardly distinguish from natural cirrus clouds."

Dr Hermann Mannstein, of the German Aerospace Centre (DLR), agreed astronomy would become more difficult, but said there was an upper limit on the contrail problem.

Contrails form where the air is highly saturated with ice particles, but will not form if the air is too dry.

"You don't clog the whole sky. You have a certain proportion of the sky, in time and space, that can be affected," he said.

Restriction zones

But Professor Gilmore countered: "There are places where you get relatively fewer clouds - that's where we put our telescopes - but there is nowhere on Earth that you don't get clouds and aeroplanes.

"Already, around the major observatories, there are local laws to prevent aeroplanes flying within quite large distances," he told the BBC News website.

Professor Gilmore said sites where observatories are located, such as the Canary Islands, Hawaii and South America, are also attractive holiday destinations, and likely centres for future air traffic growth.

He added that the projections did not factor in the effects of global warming, which are likely to exacerbate the problem.

Mr Pederson said too few satellites built up image data on how contrails evolved over time.

"We may underestimate the amount of contrail-derived cirrus clouds," he said.

"We know from satellite imagery that clusters of contrails can last for two days. If carried by the upper jet stream through the troposphere, they can travel hundreds of kilometres."

There are several concepts under consideration for the European ELT, but the preferred design seems to be converging on a telescope that is some 30-60m in diameter.

A location has not been decided; but, despite the difficulties of access, Antarctica may become an option. The icy region has relatively clear skies, with a climate that is somewhat separate from other continents, and, crucially, is free from overflying commercial jets.

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WOW Grant that certainly spells it all out to us in no doubts don't it?

its just unbelievable that the Missuse of the planets resources can still just continue at such an alarming rate

the reports a definitely food for thought lets hope some of these observations will be taken more seriously and quickly too!

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The one thing I have against this article (other than it's unsubstantiated fiction) is that surely, his basing his judgements on todays technology, in 50 years, who knows what ground-based scope technology we will have? Imagine how far we've come in the last 50 years. Obviously, that isn't a substitute for ensuring we have clear skies, but, all of these articles lately about how many planes will be flying and how many journeys will be made a day in the future, don't people realise, oil is running out, oil is getting more expensive, therefore, flights will get alot more expensive, people won't be able to afford to make as many flights so there is a case to be made for there being less flights in the future, or am I missing something?

Hmmm, imagine a pedal aeroplane :laugh: Would stop the Deep vein thrombosis...

Anyways, maybe I'm missing somethign :insects1:

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Did anyone see the program about global dimming, In one part of the program a guy took some measurements when all the planes were grounded in the U.S after 9/11 and found a significant rise in the temp. Itmay turn out that atmospheric pollution, i.e soot particles, may be stopping some of the suns heat from reaching the ground (its reflected back into space) may be masking the effects of global warming, its already shown that since the introduction of unleaded fuels and smoke scrubbers etc. that there has been a measurable increase in the amount of the suns heat reaching the ground.

Martin 2

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  • 3 years later...

By 2050 i'll most likely be too old and too mobility impaired to use a scope so i wont worry. I'll spend my nights on the computer sipping vodka and diet coke looking at Stellarium while listening to Metallica on my "geeze Grandad that MP3 player is OLD" MP3 player.

Edited by LukeSkywatcher
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By 2050 i'll most likely be too old and too mobility impaired to use a scope so i wont worry. I'll spend my nights on the computer sipping dry sherry looking at Stellarium while listening to Metallica on my "Damn Grandad that MP3 player is OLD" MP3 player.

Whilst muttering " that MP15 is overrated in my opinion" :)

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It would be an absolute travesty if the conclusions of that article came to pass. Peopleand governments are now realising the enormity of the problem that faces us over the next 50 yrs or so. My belief is that positive actions willtake shape to combat global warming - and it will have some effect. But right now we are already committed to another 10-30 yrs of warming based on what has gone before.

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  • 1 year later...
Well I'll be in my late 70's hopefully....

but then we will all still have to be working until that age anyway.

Steve

Well, unless I live to be 93 I won't be around then anyway :smiley:

Besides, we might not be using jet engines by then. Ion drives maybe or something not yet thought about.

Brinders

Edited by Brinders
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All this shows is that you can find someone, somewhere willing to speak out about any opinion. This guy can't say what will happen in 40 years time. He has no privileged information about air transport or even if there'll be enough oil left to fuel the planes.

If it was just this one guy showing a lack of judgment by ranting on about things he can't possibly know about, that wouldn't be too bad. However for a TV station to show even worse judgment by giving him a platform is ridiculous. they call him an expert - but he's not. He's an astronomer, so he knows about astronomy - not about economics or climate science. He really should learn to not talk about things he knows nothing about and the BBC should know better than to publicise this.

Edited by pete_l
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