Earth Is Getting Dimmer (gizmodo.com) 40
Earth is losing some of its glow, a study published in Geophysical Research Letters last week shows. It appears climate change and a natural climate shift have essentially scuffed up our planet. From a report: The study takes a look at earthshine, or the light reflected from the planet that casts a faint light on the surface of the Moon. It's also known as the Da Vinci Glow, because Leonardo da Vinci was the first person to formally write about it. Research has advanced quite a bit since da Vinci's writing 500 years ago, and the new findings use two decades of earthshine data collected at Big Bear Solar Observatory using a special type of telescope to view the Moon. The best time to observe earthshine is when the Moon is waxing or waning. Look at the Moon then, and you may be able to make out a faint outline of the whole Moon in addition to the sliver brightly illuminated by the Sun. That ghostly outline is thanks to earthshine, caused by the sunlight reflecting off our planet.
The observatory is perfectly situated to measure earthshine for 40% of the planet, spanning the Pacific and parts of North America. Analyzing the data for roughly 800 nights between 1998 and 2017 showed a small but significant decline in earthshine. There were some year-to-year shifts, but the paper notes that those are "quite muted, with a long-term decline dominating the time series." The scientists used satellite data to gauge what drove the dimming. Land, ice, clouds, and open ocean all have different levels of reflectivity that contribute to earthshine. (The reflectivity of different surfaces is also referred to as albedo.) The findings point to the disappearance of clouds in the tropical Pacific as the culprit in dulling Earth's shine. "The albedo drop was such a surprise to us when we analyzed the last three years of data after 17 years of nearly flat albedo," said Philip Goode, a researcher at New Jersey Institute of Technology and the lead author of the report, in a statement.
The observatory is perfectly situated to measure earthshine for 40% of the planet, spanning the Pacific and parts of North America. Analyzing the data for roughly 800 nights between 1998 and 2017 showed a small but significant decline in earthshine. There were some year-to-year shifts, but the paper notes that those are "quite muted, with a long-term decline dominating the time series." The scientists used satellite data to gauge what drove the dimming. Land, ice, clouds, and open ocean all have different levels of reflectivity that contribute to earthshine. (The reflectivity of different surfaces is also referred to as albedo.) The findings point to the disappearance of clouds in the tropical Pacific as the culprit in dulling Earth's shine. "The albedo drop was such a surprise to us when we analyzed the last three years of data after 17 years of nearly flat albedo," said Philip Goode, a researcher at New Jersey Institute of Technology and the lead author of the report, in a statement.
Solution (Score:2)
Burn more coal.
Re: Solution (Score:5, Interesting)
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Life (Score:5, Funny)
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Nerds are the worst at this because they believe that working in technology makes them educated, rational and informed.
What about the energy wasters... (Score:2)
Does this include the Lexar-like sites that put energy into the form of light, then sends it upwards towards space?
Shouldn't 'earthshine' (Score:3)
be an alcohol made on the moon under the earth light?
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be an alcohol made on the moon under the earth light?
Once said, it can never be unsaid.
Tell Elon. I'm sure he'll be on it right away.
Clouds are a big deal (Score:3)
Whether caused by climate change or other, albedo changes esp. clouds will cause further climate change. Direction uncertain -- the clouds reflect incoming solar energy (albedo cools) but also reduce IR losses from the surface (not visible, warming).
Cleaner ship emissions? (Score:2)
It's well known that particles in ship emissions seed clouds. Perhaps (I dont know) ship emissions are getting cleaner so less clouds over the oceans? Yes, this would only apply for the last 150 years or so but how accurate are earthshine measurements before then anyway?
Air traffic? (Score:2)
I wonder if the decline in air traffic over the past two years has been a contributing factor: fewer contrails = reduction in cloud cover. The study doesn't mention this though.
Reason is obvious (Score:1)
We are covering too much of our planet's surface with low albedo photovoltaic collectors.
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We are covering too much of our planet's surface with low albedo photovoltaic collectors.
That's easily solved. We just have to cut down more low-albedo trees and replace the forests with concrete. :-D
Solution (to the real problem) is easier (Score:3)
The real problem with solar panels having a (much) lower albedo than the area they cover is that they absorb light energy and turn it into heat, raising warming on an ongoing basis, much as emitted carbon dioxide from burning fossil fuels absorbs and converts light energy on an ongoing basis.
Panels do this whet
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Also more down-directed outdoor lighting (Score:2)
Reason is obvious We are covering too much of our planet's surface with low albedo photovoltaic collectors.
Yep.
Also: We've been rapidly replacing outdoor lighting with newer units that are better at directing the light only downward.
Part of that is the quest for energy efficiency: LEDs are very good at directing light at the ground and not wasing it lighting the sky or shining into the drivers' eyes.
But skyglow has been a gripe of the astronomers for decades, and manufacturers of outdoor lighting fixtur
Damn anti-vaxxers lowered our avg. IQ (Score:1)
not my fault
Which one is it? (Score:2)
"small but significant decline in earthshine" is the decline small or significant? Because the person who wrote the article forgot to take English classes.
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both. In this case "but" indicates that while one might normally expect small to lead to insignificant, it is in fact significant anyway.
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At least in science, small = low magnitude, significant = meaningful, these are not mutually exclusive.
For example, let's say your network traffic is very stable at 1GB/day because your machine always does the same thing, one day, it is 1.01GB, it is small because it is just 10MB, but it is significant because it shouldn't happen, and it may indicate a bug, an attack or an unusual event.
Now, let's say you are playing poker every day, as a pro. One day, you win 10x more than usual, this is large, but not sig
Waxing or waning? (Score:2)
> The best time to observe earthshine is when the Moon is waxing or waning.
This does not really narrow it down.
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> The best time to observe earthshine is when the Moon is waxing or waning.
This does not really narrow it down.
Sure it does, if you interpret it as "the parts of the lunar cycle when you have a roughly even divison between the lit and unlit areas".
However, I'd think that the days just surrounding new-moon would be better, when nearly all the surface is lit by earthshine and it's not exaggerated by retro-reflection or washed out by large areas of directly-illuminated ground.
The Earth is getting dimmer! (Score:2)
Vangelis is going to have to rename the song (Score:4, Funny)
Nice missummary, OP (Score:3)
From the summary title: "...It appears climate change and a natural climate shift have essentially scuffed up our planet.."
From the study: "...It is unclear whether these changes arise from the climate's internal variability or are part of the feedback to external forcings...."
What they notice is that the dimming seems to CORRELATE (not "cause") with climate forcing. They (correctly) don't seem to draw the conclusion that A caused B, because a correlation could just as well mean B causes A.
In fact, their data is observational. I'd like to see a climatologist explain how "warming" results in FEWER clouds when there is a direct increase in evaporation with increased surface temps.
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I'd like to see a climatologist explain how "warming" results in FEWER clouds
That's easy. When temperature rises, the air can absorb more moisture before reaching its saturation point.
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https://www.space.com/clouds-i... [space.com]
I dunno, at least according to "scientists" 97.5% the other direction.
"By using a new approach to analyzing data from satellites, scientists in a new study suggest that Earth's clouds could exacerbate global warming over time. This work, conducted by researchers at Imperial College London and the University of East Anglia in the U.K., provides evidence that suggests that it is very likely â" with an approximately 97.5% probability â" that clouds will amplify global
Rush put it so much better: and to music (Score:1)
> The best time to observe earthshine is when ...
Cf.
On certain nights
When the angles are right
And the moon is a slender crescent
It's circle shows
In a ghostly glow
Of earthly luminescence
I knew it! (Score:1)
I doubt it (Score:2)
It doesn't make a whole lot of sense. A warming earth (what is now euphemistically called "climate change") puts more water into the air. More water in the air leads to more clouds. More clouds increase Earth's albedo. Increased albedo means more earthshine. Unless there is some reason why more water in the air does not lead to more clouds, it would appear that whoever is claiming that "climate change" is leading to less earthshine is partaking of too much moonshine.
My summary of the study... (Score:1)
It is unclear whether these changes arise from the climate's internal variability or are part of the feedback to external forcings.
The TLDR of this study was pretty much this (IMO):
- There are some changes to albedo
- The scientists we were surprised by the aforementioned changes
- The scientists don't know if this is a cycle or a trend
- The scientists don't know what the root cause is
Things that might sway your weighting of the study:
- The sample set was 1529 from a potential 729
It's obviously dimmer due to the virus. (Score:1)
Ever Since (Score:2)
The Earth has been getting dimmer ever since the birth of BeauHD.
Fixed that for you.