Almost all computers in the Physics and Astronomy department are using internal IP addresses. This means that unless someone is on the BYU internal network (on campus, ResNet, etc) then they will not be able to access nearly all the computers in the department from home or where ever they may be outside of BYU.
There is, however, a solution. BYU OIT provides a program to gain access to internal computers if someone wants access to their office computer from outside BYU.
Go to the department documentation wiki page on VPN access and sign in with your BYU credentials for instructions on how to download and use BYU's VPN Client.