Planetary astronomers can make a good case that our moon was created in the early, ultraviolent days of the solar system when a planet about the size of Mars smashed into the early Earth. Debris from the titanic collision coalesced to form a stable binary planet, giving rise to the Earth-moon system we see today. But the details of that idea are still up for debate and a new study suggests that the relationship between the two nascent bodies may have been much more volatile:
“We’ve been calculating the past orbit of the Moon wrong for over fifty years now,” notes Cuk citing the work of then-doctoral student Chen. “We ignored the fact that tidal flexing within the Moon can decrease lunar orbital inclination.” ... Cuk and Stewart, together with Douglas Hamilton of the University of Maryland and Simon Lock of Harvard, propose a new solution to the mystery of the lunar orbital tilt, one that also explains the Moon’s Earth-like make-up. They find that, if Earth originally spun on its side with the young Moon orbiting around its equator, solar gravitational forces could both take spin away from the system and tilt the Moon’s orbit.
In this scenario, the Earth would have rotated every two hours and laid on its side relative to the solar system after the collision, not unlike Uranus rolls along on its side today. Gravitational effects both subtle and gross then teamed up to right the Earth back to its familiar obliquity, around 23 degrees, leaving the sightly tilted lunar orbit as sole witness to the ancient drama.
The proof, of course, will be in the testing. Boom plans to publicly unveil its design for a supersonic plane in the near future. The company will then team up with Virgin Galactic to build and test a prototype at Edwards Air Base in California by the end of 2017. The hope, Scholl says, is to have a working plane in service by “the early 2020s.”
- Professional and citizen scientists will amass data and weigh in anew on a classic astronomical mystery now unfolding, but it only provides a few clues once every 27 years:
Astronomers strongly suspect the dimming is some sort of eclipse event, in which an orbiting companion periodically passes in front of Epsilon Aurigae and blocks a portion of its light. Since 1821, astronomers have seen the star fade 7 times, every 27 years or so. And yet, as predictable as these eclipses have been, the underlying cause remains one of the oldest mysteries of modern astronomy.
Dubbed the Jacuzzi of Despair by the scientists who discovered it, the brine pool “lake” is like an alien world. “It was one of the most amazing things in the deep sea," says Erik Cordes, associate professor of biology at Temple University ... “You go down into the bottom of the ocean and you are looking at a lake or a river flowing. It feels like you are not on this world.”