To get your bearings on the horizontal time axis of this plot, it is useful to calculate the age of the universe in seconds today. if you multiply the age of the universe in years by the number of seconds in a year, approximately what is the current age of the universe in seconds?

As far as I know, the accepted age of the universe is Planck's measurement of approximately 13.82 billion years. Using this number, and the number of seconds in a non-leap year which we can calculate:

1 minute = 60 seconds
1 hour = 60 minutes = 3,600 seconds
1 day = 24 hours = 86,400 seconds
1 year = 365 days = 31,536,000

Now we can multiply this number by the age of the universe in years:

31,536,000 * 13,820,000,000 = 4.36x10^17 seconds

Therefore 4.36x10^17 seconds is a rough approximation of the age of the universe in seconds.