Rock Age Paradox

If a rock on Mercury formed at the same time as a rock on Earth, the rock on Earth will be older than the rock on Mercury. 

Why? 

Because Mercury is moving faster than Earth and it is closer to the sun, the sun's gravity slows down time and so does speed. The faster you move, the more your time slows down. The more gravity is near you, the slower time passes. 

It's a paradox because in the example, both rocks formed at the same time, but the one on earth is older. 

Birthday Paradox

It is possible to be born before someone but still be younger than they are. 

If you were born in London England at 1:00 AM and your friend in America was born 2 hours after you, their records would show they're a day older than you. This is because they live in a previous time zone that is in the previous day. At 1:00 Am it is still 7 or 8 pm the previous day, even at 3:00 am UK time it is still the evening the previous day in America. 

image generated by artificial intelligence (ChatGPT) 

This paradox gets worse if your born on the 1st of January at 1:00 am because your American friend's records would show they're born a different year to you as well.