Just for a change, instead of focusing on a single topic, here’s a potpourri of four cool astronomy revelations generated in just the past couple of weeks:
What’s trashing our satellites?
We are dependent on the many geostationary satellites that each hover over one particular spot above the Equator, 22,300 miles up. But sometimes these sophisticated machines fail, disrupting our communications, TV service or other modern necessities.
Now, a research team has analyzed space weather conditions at the time of 26 hard failures in eight geostationary satellites over 16 years of operation. The researchers found that most of the failures happened during high-energy electron activity during the declining phases of each 11-year solar cycle. Since the next few years will be the declining phase of this current sunspot cycle #24, this boost of our understanding of the space environment, so we can improve satellite designs, is noteworthy.
Galaxies are like goldfish
They look alike. The visible universe contains 200 billion galaxies, and the most famous are the spirals, like our own Milky Way and our neighbor Andromeda. What’s weird is their resemblance after we’ve accounted for the various angles in which they’re tilted. So why do they lose their youthful mottled appearance and become so similar?
Now, two galaxy experts – Curtis Struck and Bruce Elmegreen – have found the answer using advanced computer models. These show that after a billion years or so, simple gravity changes the orbits of a galaxy’s stars, ultimately to create a steady falling-off of brightness from their brilliant orange centers to their fainter and bluer outer spiral arms.
Mature spiral galaxies are not cranked out from the same factory, but now we know why they look that way.
Earth never stayed frozen
During the Archean period some three billion years ago, the Sun was 25 percent fainter than it is today. With that much less sunlight, the oceans should have been frozen over. But they weren’t.
This is called the “faint young Sun problem.” The usual solution is that perhaps our atmosphere was so different from today that it compensated for the Sun’s youthful anemia. Now a team of researchers using a new computer climate model has found that our planet’s air probably had 250 times the present level of carbon dioxide and 1,000 times the present level of methane – and far more clouds that trapped in the heat. It all kept us warm enough way back then to have prevented our world from being one giant flying snowball.
Pulsars changing their spots
Pulsars are astounding in many different ways at once. Although they are stars, they’re each no larger than a city. And although we think of a star as gassy, a pulsar is so dense that every teaspoon of its material would outweigh a mountain. And this entire astonishing sphere spins hundreds of times per second. Finishing it off, they have intense magnetic fields a trillion times stronger than Earth’s, so that material pulled in from any companion star produces flashes of energy.
Now, for the first time, researchers have found a pulsar that changes from emitting radio waves to X-rays and back again, depending on the position of the in-falling material. The strangest visible objects just got a little stranger.
Want to learn more? To read Bob Berman’s previous “Night Sky” columns, visit our Almanac Weekly website at HudsonValleyAlmanacWeekly.com.