In the table are 7 important dates for our universe and us. The universe is 14 billion years old.
If instead the age of the universe was 24 hours , how long ago each event would be.
I solved some of date for you. you need to solve ratios and use 1 year = 3.15 107 seconds (or about pi x 107 to remember).
When using ratios, use the same units for the numerator and the denominator. (like millions years both top and bottom, or hours,
or seconds or billions years, or minutes.. )
| 7 important date | for a 24 hours day |
| birth of the universe = 14 billion years ago | 24 hours ago |
| milky way and other galaxies = 13 billion years ago | 14/13 = 24/ x so x = 22 hours ago |
| solar system (oldest meteorite ) = 4.5 billion year ago |
so x = _________
hours ago |
| emergence of life, first fossilized life = stromatoliates (blue green algae) = 3.5 billion year ago |
x = _________ hours ago |
| !!! units since we go to millions, use 14 billion = 14 000 million 550 million years ago Cambrian explosion of life, appearance of hard body parts golden age of trilobite. !!! units!! covert to millions use 14 billion = 14 000 million | 14000/500 = 24/x x = _________ hours ago = ___________ minutes ago (keep all decimals, in your TI then multiply by 60) |
65 million years ago, extinction of dinosaurs 2/3 of living species were wiped out.  which ,,, is a good thing for us |
x = _________ hours ago (keep all decimals, in your TI then multiply by 60) = ___________ minutes ago (round) |
| 4.5 million years ago, the first hominid (Lucy is a young hominid 3.5 million years old) | x = ________ hours ago (keep all the decimals and then multiply by 60) = ________________ minutes ago (keep all the decimals in TI and multiply by 60 again to find in seconds) = = __________ seconds ago |
| about 195 000 years ago ? first homo sapiens. !!! convert to standard notation !!! use 14 billion = 14,000,000,000 and 24 hours = 86400 seconds | convert before setting proportion x = ___________ seconds ago |
| 100 years ago (modern Physics era ) or our life time | x = __________ seconds compared to the Universe history. Use scientific notation. (order of 10,000th of a second !!!) |