Science In the April issue, Michael Rampino wrote about cycles of comet collisions with Earth every 26 million to 30 million years. Is there evidence of cyclical bombardment on other planets or moons?
Exoplanets, Stars Exoplanets the size of Earth cannot be seen directly; however, white dwarfs can. Is this due to their brighter appearance?
Stars In the May issue, Phil Harrington says M5 “may contain as many as 500,000 stars crammed into a space about 165 light-years across.” Why don’t they all coalesce into one giant star?
