We’ve talked about what a “year” is, and how that relates to your birthday: it’s the time our Earth takes to go all the way around our Sun. We’ve also talked about how other planets like Mercury go around faster. Well, there’s an even speedier planet out there that goes around its own sun in just 8 hours! Wherever Kepler-78b is right now, 8 hours from now everyone there will already be a “year” older in their time. Actually, nothing lives there. The planet goes fast because it’s so close to its sun. So its temperature is between 3000 and 5000 degrees. The whole planet is molten lava, the same hot stuff from inside a volcano. So yes, we Earthlings have to wait longer for our birthdays, but we’re a lot more comfortable here.
Wee ones: If you’re going to have 3 birthdays today, what ages will you turn today? Count up 3 years from your age!
Little kids: If your 2nd “birthday” today is at 1 pm, at what time is your last one 8 hours later? Bonus: If you serve cake only on every 4th birthday, including your middle one today, at which birthday will you serve cake again? (Just the day and first/middle/last, not the time).
Big kids: If your 1st birthday was today at 7 am, at what time was your last birthday yesterday? Bonus: If you get 3 birthdays a day, how old will you be 1 Earth week from now?
Wee ones: Different for everyone…count up the next 3 numbers from your age today!
Little kids: At 9 pm. Bonus: At your last birthday tomorrow.
Big kids: At 11 pm (since midnight was just 7 hours earlier). Bonus: Different for everyone…add 21 to your age!
Laura Bilodeau Overdeck is founder and president of Bedtime Math Foundation. Her goal is to make math as playful for kids as it was for her when she was a child. Her mom had Laura baking before she could walk, and her dad had her using power tools at a very unsafe age, measuring lengths, widths and angles in the process. Armed with this early love of numbers, Laura went on to get a BA in astrophysics from Princeton University, and an MBA from the Wharton School of Business; she continues to star-gaze today. Laura’s other interests include her three lively children, chocolate, extreme vehicles, and Lego Mindstorms.