Post
by **GoatGuy** » Sat Feb 17, 2024 5:01 pm

Lovely shot.

I was wondering how big such a meteor could be. Various sources say things like 'less than a centimeter' and 'millimeters or so'. I guess so. Then I decided to use the other "can be brighter than Venus" to work some Excel magic, to figure out how big a bit-o-dust it might have been.

Using drivers of

Venus insolation = 2700 W/m²

… diameter 12,000 km

Bright arc of 30%

Bright distance about 75% of 1 AU from Earth

Determined that Venus must bathe Earth with about 1.3×10⁻⁶ W/m² at its brightest. Then went on to ask mathematically "how much output would a meteor at 45 km altitude have to produce in order to also have that 1.3×10⁻⁶ W/m² where the observer is standing?"

That turned out to be 34,000 W of optical power.

From there and E = ½mv², estimating the velocity at 30 km/s, then the little morsel need only weigh in at 0.07 grams. And, while that's not very much, if the meteor is 'stony' say, with a 6 g/cm³ density, then that's about 0.012 cm³, 0.28 cm diameter, about 3 millimeters.

3 mm is yep … still a grain of sand … but not fine sand. Big coarse sand.

Working that 100% backwards, all the numbers confirmed out pretty well. So … 3 to 10 mm chunk of star stuff! Yay!

⋅-⋅-⋅ Just saying, ⋅-⋅-⋅

⋅-=≡ GoatGuy ✓ ≡=-⋅

**Goat**Guy -- Because *discussion is awesome* especially when debating facts...