So while they say that it will miss if it passes on the 5th, but they are noticeably silent as to what might happen on the 2nd, 3rd, 4th or 6th. Since we are only safe on one of the 5 days, simple math shows that there is an 80% chance it will hit.
You have to carefully parse anything that comes from the government, and look closely at what they don't say.
“You have to carefully parse anything that comes from the government, and look closely at what they don’t say.”
You also need to remember to take your meds.
The NASA NEO uncertainty predictions are made by repeated monte carlo simulations from the best know state of the object, in this case its state on October 9, 2013.
Starting at October 9, 2013, we have an estimate of the state of the object and an estimate of the uncertainty (covariance) of the state.
We make a draw from a process which produces random states with the same mean and covariance as our estimate, and propagate that state forward in time one hundred years into the future and note its closest approaches to earth along the way. We make repeated draws, millions, and use the results of millions of such simulations to characterize the near encounters with earth and the likelihood of a collision with the earth in the next century. (They are only funded to make 100 year predictions, but they publish the state and covariance, so outsiders are welcome to give it a go.)
The technique is thorough, and produces estimates about as good as anything. So they didn’t overlook March 2nd, or 7th or any other day in the next century.