On a flight across the ocean your plane crash-lands on a remote island with no one around to help. Everyone survives but has amnesia (memory loss), so no one can remember the date. Everyone's belongings were destroyed when the plane crashed... How could you figure out roughly (estimate) what month it is?

you can have just about every answer you can think of

sound moves fastest in solids because the molecules are tightly packed and it allows sound to vibrate

the circled areas are referred to   as sunspots.   the sunspots are cooler than the   surrounding area.

sunspots are temporary phenomena on the photosphere of the sun that appear visibly as dark spots compared to surrounding regions. they correspond to concentrations of magnetic field flux that inhibit convection and result in reduced surface temperature compared to the surrounding photosphere.