1) The smallest unit of time is known as a zeptosecond, which is equal to one trillionth of one billionth of a second.

2) Leonardo DiCaprio is an acclaimed American actor and environmental activist. He has starred in numerous successful films, including "Titanic," "The Revenant," and "The Wolf of Wall Street," and has been recognized with several awards, including an Academy Award.

3) The Northern Lights, also known as the Aurora Borealis, are natural light displays that occur in the polar regions due to interactions between the Earth's magnetic field and solar particles.

4) The shortest scheduled commercial flight lasts just 1.7 miles and connects two Scottish islands, Westray and Papa Westray.