It’s currently estimated at about 3 trillion https://www.nature.com/articles/nature14967.epdf?referrer_access_token=po4o_VgbMYPJgT4pKT6TUdRgN0jAjWel9jnR3ZoTv0PkYJmQ6VQcpxIB4Tt0SaQyPKfpzs4TggJ7knJl_7tgGSO9OHjQZhexvTrRbbxeJ3Mn5uNk8MZCboMj6EN3hlJIb2MDrUQLunUVZL1yAlvsD1O0MO-FOQ8hTYe1754zdAt0E2-3MjoycrWEKKyfDo-t4-gdDKQbiD8CzxQeGO3ZWCngUrGs88WzY7Rte6fDytWmWIJt6EmEbCeHCX9LJcblJS_6-dlTzs6PZ9R7AwyZ1w%3D%3D&tracking_referrer=www.scientificamerican.com …
-
-
-
Tree treellion?
End of conversation
New conversation -
-
-
Thanks. Twitter will use this to make your timeline better. UndoUndo
-
Loading seems to be taking a while.
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.