I remember once watching a PBS Science show one evening about cosomology, space and the topic of the Sun seemed to be central to this one episode. I remember a scientist being interviewed and he dropped a statistic, a figure of some sort about the mass of the energy hitting the Earth in the form of sunshine, solar radiation. But I didn’t have a digital video recorder (remember those?) nor was I taping the program with a VCR (remember those?) and I wasn’t listening very closely (not we can all remember that). And I couldn’t rewind to hear what the numeric value was.
And in all the time since then, I wondered what did he say? Maybe I could look-up the program and seek around with the playbar and find that segment again. Or, maybe there’s a transcript on the web that a search engine indexed. And the numeric value would be IN that transcript.
And dear reader in all that time, I’ve never found it. I would remember now and again, “Hey I wonder if I can find out that number again”. And then attempt to find the missing video, transcript what have you. But I never did, I was lazy and I gave up. This is not to say I “couldn’t” have learned how to do this calculation myself. I could have looked up how much energy reaches the surface of the Earth every minute. I think that figure might have been figured out some time ago (Climate Science being top of mind since the day I was born). And from there use good ol’ A.Einstein’s General Relativity equation to turn Energy = mass times the square of the speed of light. And solve for “m” to get the weight/mass of the Sunshine hitting the Earth every minute.
So what’s different now? Well we have the Large Language Models and their associated Chat interfaces to just effortless plug-in a text string and get something back that sounds vaguely like an answer IF we had enough knowledge and expertise, and most of all,… motivation. But it’s Saturday morning, and I need to do the chores. So I give up, DuckDuckGo Assistant do your worst. Just tell me the answer.
Weight of Sunshine Hitting Earth
Energy from Sunlight
The sunlight that reaches the Earth is measured in terms of power per unit area. The solar constant, which is the amount of solar energy received at the Earth’s surface, is approximately 137 milliwatts per square centimeter (mW/cm²) when the sun is directly overhead.
Calculation of Energy
To estimate the energy from sunlight hitting the Earth every minute, we can use the following calculation:
- Solar Constant: 137 mW/cm²
- Area of Earth: The Earth’s surface area is about 510 million square kilometers, or 5.1 x 10^12 cm².
Total Energy Calculation
- Energy per second:
- Energy = Solar Constant × Area
- Energy = 137 mW/cm² × 5.1 x 10^12 cm² = 7.0 x 10^13 mW = 7.0 x 10^10 watts
- Energy per minute:
- Energy per minute = 7.0 x 10^10 watts × 60 seconds = 4.2 x 10^12 joules
Weight of Sunshine
To convert energy to weight, we can use the equivalence of mass and energy given by Einstein’s equation E=mc2:
- Speed of Light (c): Approximately 3 x 10^8 m/s
- Weight (mass):
- Mass = Energy / c2
- Mass = 4.2×1012 joules/(3×108 m/s)2
- Mass ≈ 4.67 x 10^{-5} kg
Summary
The weight of sunshine that hits the Earth every minute is approximately 0.0000467 kg, or 46.7 milligrams.
And “what” pray-tell was the motivation to even do this look-up? And I am glad you asked that question. It was social media! A person I follow quoted the Ecology writer Bill McKibben on current events in the Middle East. The quote was shared by a College Professor I follow on Mastodon.The quote was as follows.
“Sunlight travels 93 million miles to reach the earth
None of them through the Strait of Hormuz“
– Bill McKibben
And why this is important, matters etc. is that in spite of all the hubbub, turmoil, DOGE’ing going on the Sun cares not for the little Universe on this Pale Blue Dot (as Carl Sagan describes). The Sun goes on, warming up this planet, radiating energy and we just are so wrapped tight as World Leaders with our heads in the sand, not looking up, that by the time any of this is put the bed, put to rest, written up in History books, there won’t be any more time to save ourselves. The Sun is a honey-badger (like that YT meme of yore), it don’t care.
Carpet Bomberz Inc. 