The first day of fall or Autumnal Equinox marks the start of fall in the Northern Hemisphere. The first day of fall in 2018 will fall on the 22nd September at 9:54 pm ET. During the Autumn equinox, the length of day & night is almost equal. The Sun moves from North toward the South crossing the equator
Vernal equinox or March equinox indicates the first day of spring in the northern hemisphere. At this point, both north and south hemispheres receive an equal amount of sunlight as the sunlight fall perpendicular to the equator. The first day of spring in 2018 fell on March 20, 2018, at 12:15 pm ET
Yes, it is safe to swim while you on periods. Period blood doesn't flow outside the vagina like it usually does due to the counter-pressure of the water. But You still need to wear some a tampon or a menstrual cup to avoid getting into a sticky situation.
Resin tooth filling typically contains a filler particle such as quartz, which provides the mixture's strength and color. It is costly as compared to silver tooth filling.
In some cases, the change in period blood color can indicate a health problem like fibroids, low estrogen levels, and even vaginosis.