It's hard though, to imagine what impact you might have on those far-flung future descendants. It's hard enough to figure out your impact on your children! We don't even know how many of those people will know who we were.
We can assume that we won't all be monumental and have statues will be built in our memory. We won't all discover something amazing and be immortalized in books. We won't all be fantastically wealthy and pass down trusts.
We, however, have today to pass on. We have the time now to make the world a better place and to leave a lasting impression that should carry forward for generations to come. How we live our lives, striving to make today a good day, can be our greatest legacy.
We are not only passing this possible inheritance to our own progeny. What we do today and how we make today a good day can and will influence all the people we deal with and could influence their family futures.
Not knowing the impact does mean that there isn't one and it doesn't mean that you shouldn't try to make that impact positive. Not knowing means that today is the day to make sure you are doing something that has the chance of being the change that lasts lifetimes.
As we go through today, remember that our good day can have impacts that will matter long after we have gone. Our children and their children and their children and some random children can have a better life because of choices we make today. Do something that will make you a good ancestor.