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Give Thanks for the Winter Solstice. You Might Not Be Here Without It.
The axial tilt of Venus, for example, is so extreme — 177 degrees — that the planet is essentially flipped upside down with its South Pole pointing up. Perhaps counter-intuitively, that means that there’s very little tilt to its upside-down spin and its hemispheres will never dramatically point toward or away from the sun. As such, the sun’s dance across the sky will remain relatively stable — shifting by a mere six degrees over the course of a Venusian year.

Had we evolved on Venus, it’s likely that we would not have noticed solstices or seasons at all, said David Grinspoon, an astrobiologist at the Planetary Science Institute.

The same can’t be said for imaginary aliens living within Uranus’s chilly blue clouds.

“Uranus is wild,” Dr. Grinspoon said.

An axial tilt of 98 degrees causes the ice giant to spin on its side. So, whereas one of Earth’s poles leans slightly toward the sun at solstice, one of Uranus’s poles points almost directly toward the sun at solstice — as though poised to make a perfect bullseye. That means that one hemisphere will bask under the sun both day and night, while the other will experience a frigid and dark winter and not catch a glimpse of the sun for that entire season.
astronomy  astrophysics  evolution 
4 weeks ago by campylobacter
Deathblow Dealt to Dark Matter Disks | Quanta Magazine
New data tracking the movements of millions of Milky Way stars have effectively ruled out the presence of a “dark disk” that could have offered important clues to the mystery of dark matter.
articles  astrophysics  cosmology 
4 weeks ago by gmisra
Earliest Black Hole Gives Rare Glimpse of Ancient Universe | Quanta Magazine
It weighs as much as 780 million suns and helped to cast off the cosmic Dark Ages. But now that astronomers have found the earliest known black hole, they wonder: How could this giant have grown so big, so fast?
articles  astrophysics  space 
5 weeks ago by gmisra
Gpredict: Free, Real-Time Satellite Tracking and Orbit Prediction Software
Gpredict is a real-time satellite tracking and orbit prediction application. It can track an unlimited number of satellites and display their position and other data in lists, tables, maps, and polar plots (radar view). Gpredict can also predict the time of future passes for a satellite, and provide you with detailed information about each pass.

Gpredict is different from other satellite tracking programs in that it allows you to group the satellites into visualisation modules. Each of these modules can be configured independently from the others giving you unlimited flexibility concerning the look and feel of the modules. Naturally, Gpredict will also allow you to track satellites relatively to different observer locations - at the same time.

Gpredict is free software licensed under the GNU General Public License. This gives you the freedom to use and modify gpredict to suit your needs. Gpredict is available as source package as well as precompiled binaries for Linux, Mac OS X, and Windows via third parties.
space  astrophysics  astronomy 
6 weeks ago by kmt
Galactic Glow, Thought to Be Dark Matter, Now Points to Hidden Pulsars | Quanta Magazine
A number of high-energy anomalies raised hopes that astrophysicists had seen their first direct glimpses of dark matter. New studies suggest a different source may be responsible.
articles  astrophysics 
8 weeks ago by gmisra
‘Crazy’ Supernova Looks Like a New Kind of Star Death | Quanta Magazine
Astronomers are mystified by a strange star explosion in a distant galaxy that might be a relic from an earlier cosmological era.
articles  astrophysics 
9 weeks ago by gmisra

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