[0] https://bionumbers.hms.harvard.edu/bionumber.aspx?id=100943
(Life has evolved on the edge of a knife, at the narrow balance point between enormous energies that cancel out just so. I often think that at the beach, looking out across the ocean, marveling that the water is almost never sloshing around at any scale proportional to itself. It's up to us to educate those who don't understand positive feedback loops and the existential risk they present to any system in equilibrium.)
You mean watt days (watts * days).
It is akin to thinking that "2 apples" and "an apple divided by 2" are interchangeable because both expressions involve the concept of an apple and the number 2.
i'd definitely rewrite it myself, but it's also a correct way to specify that there are no days of the week, year, or whatever (solar cycle) in which the terawattage is below 170k. Not very intermittent, is it!
I agree with you, FWIW.
watts/unit thus seems fine to me, whatever the unit may be, even if it itself is derived from time. watts per day would just work out to joules/second/1/24*60*60, making 1 watts per day a derived unit that expresses joules/84600 seconds, or an instantaneous rate of one 84600th of a joule.
It's the opposite: joules/day and watts are both units of power.
- A̶ ̶w̶a̶t̶t̶ ̶i̶s̶ ̶d̶e̶f̶i̶n̶e̶d̶ ̶a̶s̶ ̶1̶ ̶j̶o̶u̶l̶e̶ ̶p̶e̶r̶ ̶s̶e̶c̶o̶n̶d̶
̶ A̶ ̶w̶a̶t̶t̶ ̶f̶o̶r̶ ̶1̶ ̶s̶e̶c̶o̶n̶d̶ ̶t̶h̶e̶r̶e̶f̶o̶r̶e̶ ̶e̶q̶u̶a̶l̶s̶ ̶1̶ ̶j̶o̶u̶l̶e̶,̶ ̶a̶ ̶m̶e̶a̶s̶u̶r̶e̶ ̶o̶f̶ ̶e̶n̶e̶r̶g̶y̶
- A̶ ̶T̶e̶r̶a̶w̶a̶t̶t̶ ̶f̶o̶r̶ ̶a̶ ̶d̶a̶y̶ ̶i̶s̶ ̶t̶h̶e̶r̶e̶f̶o̶r̶e̶ ̶a̶l̶s̶o̶ ̶a̶ ̶m̶e̶a̶s̶u̶r̶e̶ ̶o̶f̶ ̶e̶n̶e̶r̶g̶y̶.̶
[edit: The earth receives 14.9 ZettaWatts of solar power per day, and 173 Petawatts per second, I was reading it as 173 PW over a day, in which case the above works fine. Mea culpa]
See: https://gosolarquotes.com.au/amount-of-solar-energy-hitting-...
Power (kg m^2 / s^3) * Time (s) = Energy (kg m^2 / s^2)
Now from context it's obvious that what was meant is that Earth continually receives 170 terawatts from the sun. The phrasing is technically inaccurate, but it's a turn of phrase that works fine.
[1]: https://gosolarquotes.com.au/amount-of-solar-energy-hitting-...
"Earth gets over 170,000 terawatts of solar energy every day"
= 170 PW × 1d
= 170 × P(J/s) × 86.4 × ks
= 170 × 10¹⁵ × (J/s) × 86.4 × 10³ × s
= 14.6 × 10²¹ × J
= 14.6 ZJ
However, I also think "of solar energy" could be read as specifying the type of energy for the "rate of energy transfer", which is already implied in 'watt'. And since it's related to energy usage (rate), there really is no need to leave the "rate of energy transfer" interpretation at all and get hung up on "energy vs. power":
"Earth receives 170 petawatts as solar energy - 10,000 times the energy humanity uses, at any moment.
Edit: And let's be real, we all only feel very smart here because we just watched the latest Technology Connections video https://www.youtube-nocookie.com/embed/OOK5xkFijPc :D
Watt*day is a perfectly cromulent energy statement although a bit misleading.
Really common mistake in general to use kWh as a kW. Watthour is unit of energy. As watt is energy by time period. So you get back to units of energy.
Technically watt/day could be change in power consumption.
If you pour out one bucket of sand every hour, and you do that for 10 hours, I expect the quantity of sand to be measured in buckets.