You probably know how many years old you are, but do you know what a “year” is? It’s the amount of time that Earth, the planet we live on, takes to travel once through space around the Sun. We do this pretty fast – Earth moves at over 60,000 miles an hour. Well, scientists just found an even speedier planet: it’s so close to its own Sun, it takes only 8 or so hours to go all the way around! That means wherever it is right now, 8 hours from now it will have zoomed all the way around its star, and everyone living there will be a year older already. Actually, no one lives there: the temperature is somewhere between 3000 and 5000 degrees, and the whole planet is molten lava, the same hot stuff that explodes out of volcanoes. We’re probably more comfortable here on Earth, even if we wait a long time for our next birthday party.
Wee ones: There are 7 other planets going around our Sun along with Earth. How many planets is that in total?
Little kids: If it’s 3:00 pm on Earth right now, and a year on Kepler is about 8 hours long, at what time will creatures on Kepler-78b be 1 year older? Bonus: When will they age another year after that?
Big kids: If a year on Kepler-78b is just 8 hours and the planet has 4 equal seasons like we do, how long is summer there? Bonus: If it takes about 8 hours for 1 year, how many years older will Keplerites be this time tomorrow? (Reminder: an Earth day has 24 Earth hours.)
The sky’s the limit: Assuming a year there takes a flat 8 hours, how many years old would you be on Kepler-78b?
Wee ones: 8 planets (since Pluto got demoted a few years ago).
Little kids: 11:00 pm. Bonus: 7:00 am.
Big kids: 2 hours. Bonus: 3 years older.
The sky’s the limit: Different for everyone…figure out how many days you’ve lived, then multiply by 3 to get the number of 8-hour long Keplerite years. There are lots of ways to estimate how many days you’ve lived: you can count up 730 days for every 2 years you’ve lived and then figure out the remainder, or you can count how many months and multiply by 30, and so on.