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?
Science One night I noticed a star changing colors and moving perceptibly. But through binoculars, a few dimmer stars in the same field appeared steady. The behavior continued throughout the night, but not a couple of nights later. Why?
Science How are so many exoplanets detected via transits, while transits of Mercury and Venus are so rare? Do all the chance transit alignments fit statistically?
Science, Solar System The processed images from Juno are spectacular, but they don’t resemble previous images of Jupiter. Why are they so different from those returned by earlier missions?
Science What is metallic hydrogen, and does it exist at the core of all the gas giants in our solar system?
