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Specialty Chemistry Forums => Other Sciences Question Forum => Topic started by: pnacze199204 on July 30, 2018, 11:41:22 AM

Title: What if the luminosity of Sunlight increased by 10%
Post by: pnacze199204 on July 30, 2018, 11:41:22 AM
If the luminosity of sunlight increased by 10%, would people be able to survive outside? Would such brightness of light be very harmful to them, for exemple as much as the Mercury Vapour Lamp without any protection from UV light? I omit the temperature issue, I mean the level of energy itself, because I'm curious whether man (or bacteria) could survive if he went outside completely naked?

Title: Re: What if the luminosity of Sunlight increased by 10%
Post by: Enthalpy on August 01, 2018, 04:48:59 AM
A 10% variation of UV would be negligible for living organisms I guess. The proportion of time we spend under sunlight or in shadow varies more than that.

10% change in the visible sunlight is negligible. When a cloud passes, the light power drops by 104 - even though our eyes barely notice.

But why do you make this bizarre hypothesis again and again? The Sun's output is constant. Very constant. Extremely constant. We use it to design satellites whose temperature is modelled and monitored very accurately. Any change would be perfectly known.

Maybe you read some propaganda by climate-negationists. One of their attempts is to attribute Earth's global warming to the Sun. It's b*llocks.
Title: Re: What if the luminosity of Sunlight increased by 10%
Post by: Borek on August 01, 2018, 07:32:24 AM
The Sun's output is constant. Very constant. Extremely constant.

Depends on your definition of "constant", there are observable (although minute, in the few tenths of percent range) changes depending on the rotation and the solar cycle.

https://link.springer.com/article/10.1007%2Fs00159-004-0024-1
Title: Re: What if the luminosity of Sunlight increased by 10%
Post by: Enthalpy on August 03, 2018, 06:27:47 AM
And the amount we receive depends also on the distance, since Earth's orbit is 0.017 eccentric. And so on.

Ice ages have been related to periodic changes in Earth's inclination and with the orientation of its inclination versus the seasons - over times where continents moved little. This does not explain the changes over the past millennium, but attempts to explain them by a varying Solar output are debatable and debated. In favour of less Sun power then are the fewer Sunspots observed at that time. But the tiny value of the power drop speaks against that explanation, and other causes, for instance changes at the Gulf Stream, are considered.

Anyway, changes like 10% aren't realistic in modern history, nor can the Solar output explain the present global warming.
Title: Re: What if the luminosity of Sunlight increased by 10%
Post by: Borek on August 03, 2018, 08:25:30 AM
Anyway, changes like 10% aren't realistic in modern history, nor can the Solar output explain the present global warming.

Definitely, I was merely pointing to the fact your statement was a bit too strong for the reality.