Why do some stars twinkle erratically but others don't?

I notice a few years ago that some stars, about four to count, have been twinkling erratically and changing different colors like red, green, and blue. I have never seen this as a child. Instead the night skies where filled with stars in their natural form, but now their are only but a few which are the known stars like the dipper, mars, Jupiter and so on.

When I was younger I did a lot of research about space and how stars are born. From what I learned, stars that do this erratic twinkle, means they are about to die. This is also information I gathered in the year of 1994, so I don't know if that is still accurate. But, these stars that I see now have not died, are always in the same spot, never seem to move along with the other stars, and twinkle as if they're about to explode. The twinkles also go from big to small as if there are explosions going off.

Can someone explain this? Are they stars or unidentified objects the government put in the sky? I say UFO's by the government because they have been doing strange things and it makes me wonder about the sky and what goes on up there late at night. Also tonight I went on my lunch break and those specific stars aren't up there, but there is one above the cathedral of learning that's doing what I described these other four stars do. The others strangely are not up there, and from time to time they don't appear, but most nights they are there.