1. Earth passed through a jet emitted by a radio galaxy? What would we see and what might happen to Earth? 2. A jet of gas suddenly appeared across the night sky? What might it indicate has recently...

1. Earth passed through a jet emitted by a radio galaxy? What would we see and what might happen to Earth?

2. A jet of gas suddenly appeared across the night sky? What might it indicate has recently happened?

3. Sirius suddenly became ring-shaped for a few hours and then returned to normal? What might cause such an event?