For more than 30 years, scientists have argued about a controversial hypothesis relating to periodic mass extinctions and impact craters on Earth caused by comet and asteroid showers. Now scientists conclude that these events show a cyclical pattern over the studied period, with both impacts and extinction events taking place every 26 million years.
The highlight of October for meteor observers is the Orionid meteor shower, which occurs when the Earth encounters the debris stream of Halley’s Comet. With a broad maximum 21-23 October, peak rates are typically about a quarter of those seen for the Perseids of August. A good percentage of Orionids are bright and leave persistent trains.
Earth came early to the party in the evolving universe. According to a new theoretical study, when our solar system was born 4.6 billion years ago only eight percent of the potentially habitable planets that will ever form in the universe existed. And, the party won’t be over when the Sun burns out in another 6 billion years. The bulk of those planets — 92 percent — have yet to be born.
Astronomers studying the birth of planetary systems in the young (about 2-3 million years old) star forming region IC348 in Perseus as seen by the infrared cameras onboard the Spitzer Space Telescope have found thirteen stars in this complex with detectable discs, none of which is as massive as our early solar system’s disc.
Some 300 so-called hot Jupiters have been identified over the past two decades, but how did these large, hot planets ever get so close to their suns? Now scientists have made a startling discovery: One of these mysterious hot Jupiter systems has not one, but two close-in planetary companions, leading to new clues about planet formation and migration.
One of the most important but least understood processes in astronomy is accretion, where the mass of an object grows by gravitationally collecting material from nearby. Now an international team has discovered that that the process by which astronomical objects grow is fundamentally the same, regardless of the type, mass or size of the object.
Phenomenally durable crystals called zircons are used to date some of the earliest and most dramatic cataclysms of the solar system, such as the late heavy bombardment that created hellish surface conditions on the young Earth and Moon about 4 billion years ago. Now a study of zircons from a gigantic meteorite impact in South Africa casts doubt on the methods used to date lunar impacts.
According to observations from the Tihany Magnetic Observatory in Hungary, the indices used by scientists to assess the Sun’s geomagnetic perturbations to the Earth are unable to detect some of these events, which could put both power supply and communication networks at risk. The Tihany Magnetic Observatory registered a solar storm similar to the largest one ever recorded while other observatories were completely unaware of the event.
It seems that the more we see of Pluto, the more fascinating it gets. This latest image, from the heart of Pluto’s heart feature, shows the plains’ enigmatic cellular pattern as well as unusual clusters of small pits and troughs. Adding to the intrigue is that even at this resolution of 250 metres, no impact craters are seen, testifying to the region’s extreme geologic youth.
NGC 4639 is a beautiful example of a type of galaxy known as a barred spiral. It lies over 70 million light-years away in the constellation of Virgo and is one of about 1500 galaxies that make up the Virgo Cluster. But NGC 4639 also conceals a dark secret in its core — a massive black hole that is consuming the surrounding gas and known as an active galactic nucleus (AGN).
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