Astronomy

From Belinda Smith at Cosmos: A Mercury-sized planetary embryo that slammed into Earth around 4.4 billion years ago delivered virtually all of the planet’s carbon, new research suggests. … Unravelling the early Earth’s composition is no easy feat. Billions of years ago, the solar system was a whirling mess of comets, asteroids and proto planets. … One scenario that could yield today’s volatile concentrations was if a carbon-rich Mercury-sized planet with a core full of silicon or sulfur smashed into and was absorbed by Earth. The dynamics of the collision meant the silicon sank straight to Earth’s core while the carbon was mixed with the mantle, ready to be cycled up to the crust and eventually, develop life. More. Two Read More ›

From NASA: As Juno approached Jupiter on August 27, 2016, it’s Jovian Infrared Auroral Mapper (JIRAM) instrument captured the planet’s glow in infrared light. The full story and more images from Juno’s first pass of Jupiter with all instruments on is here.

From Rachel Feltman at Washington Post: But now scientists have found something entirely new: a galaxy with the same mass as the Milky Way but with only 1 percent of our galaxy’s star power. About 99.99 percent of this other galaxy is made up of dark matter, and scientists believe it may be one of many. The galaxy Dragonfly 44, described in a study published Thursday in the Astrophysical Journal Letters, is 300 million light years away. If scientists can track down a similar galaxy closer to home, however, they may be able to use it to make the first direct detection of dark matter. More. See also: Dark matter skeptics wanted These people should really talk. Follow UD News Read More ›

It seems there is now a talking-point agenda to dismiss the fine tuning issue as an illusion. So, in the current thread on the big bang and fine tuning, I have clipped and commented on a recent article by Luke Barnes. However, comments cannot put up images [save through extraordinary steps], so it is first worth showing Barnes’ key illustration, as showing where fine tuning comes in, updating Hoyle’s remark about the C-O balance first key fine tuning issue put on the table in 1953: Let me also headline my comment, no. 77 in the thread: >>Luke Barnes has a useful semi-pop summary: http://www.thenewatlantis.com/…..tures-laws Today, our deepest understanding of the laws of nature is summarized in a set of equations. Read More ›

From New Scientist: “NASA has been shameful in not searching for extraterrestrial life and at the same time claiming that’s one of the motivations for their programmes,” says Chris McKay, an astrobiologist at NASA’s Ames Research Center in Mountain View, California. “The Mars programme counts life as the reason for the programme, and then the missions NASA implements don’t even approach the question at all.” McKay cites the example of the upcoming Mars 2020 rover, which will primarily search for signs that life once existed on the Red Planet. Rather than hunting for alien microbes today, the rover will set aside samples that NASA hopes some future mission will bring back to Earth, where we can probe them for signs Read More ›

An intriguing idea is introduced by Neel S. Patel at Inverse: The strangest thing about a black hole is that its edge, known as the event horizon, can’t be observed on account of light not being able to escape the gravitational pull. Physicists don’t really understand how an object just falls into the black hole there’s really no “in.” Everything just gets trapped in the dense gravitational flux of the surface. German physicists at the Max Planck Institute for Theoretical Physics have now created a new estimate of the amount entropy contained with a black hole — and that value suggests black holes are indeed two dimensions and not three. “We were able to use a more complete and richer Read More ›

From New Horizons:

From Nature News: Much of what scientists know about the relative contributions of dark matter and dark energy comes from the relic radiation left behind from the Big Bang, called the cosmic microwave background. The most exhaustive study of it — essentially a portrait of the young Universe at about 400,000 years of age — was done in recent years by the European Space Agency’s Planck observatory. Based on Planck’s measurements, cosmologists can predict how that young Universe will evolve, including how fast it expands at any point in its history. For years, those predictions have disagreed with direct measurements of the current rate of cosmic expansion — also known as the Hubble constant. But until now the error margins Read More ›

… Johannes Kepler freelanced as an astrologer. From Wonders and Marvels, : There were a variety of specializations within the field of astrology, from the very respectable basics of using heavenly observations to make general predictions about the weather, finances, etc., to the more controversial practice of casting a chart based on the moment a question was posed and then providing an answer according to celestial aspects.[ii] And Catherine was hardly the only monarch employing astrology or astrologers in decision-making. The severe and devout Philip II of Spain consulted them, even upon the creation of his tomb. And who has not heard of John Dee in connection with England’s Elizabeth I? It was not until the opening years of the Read More ›

Voids and supervoids: Cosmic voids, and supervoids, are large volumes of space that are devoid of matter. This includes normal matter, in the form of galaxies, and dark matter. Initially, astronomers were not sure if the voids contained dark matter, even though there were no galaxies, but recent observations show that the halos of dark matter are not present. The filamentary structure of galactic superclusters surrounds the voids. While space is mostly empty, voids are large volumes, tens of megaparsecs across. The largest confirmed supervoids are about 100 Mpc (325 million light-years) or more across . The larger known voids include the Boötes Supervoid, and the Northern and Southern Local Supervoids. To explain the cold spot in the cosmic microwave Read More ›

From Nature: Some welcome his latest report as a fresh way to solve a black-hole conundrum; others are unsure of its merits. … In a paper published in 1976, Hawking pointed out that the outflowing particles — now known as Hawking radiation — would have completely random properties. As a result, once the black hole was gone, the information carried by anything that had previously fallen into the hole would be lost to the Universe. But this result clashes with laws of physics that say that information, like energy, is conserved, creating the paradox. “That paper was responsible for more sleepless nights among theoretical physicists than any paper in history,” Strominger said during his talk. The mistake, Strominger explained, was Read More ›

Skinny via Yahoo: CAPE CANAVERAL, Fla. (Reuters) – The solar system may host a ninth planet that is about 10 times bigger than Earth and orbiting far beyond Neptune, according to research published on Wednesday. Computer simulations show that the mystery planet, if it exists, would orbit between about 200 and 1,000 times farther from the sun than Earth, astronomers with the California Institute of Technology in Pasadena said. So far, the planet has not been observed directly. Not observed directly, hmmm. But wait, there’s this: The computer model also predicted the location of other objects beyond Neptune, in a region known as the Kuiper Belt, and those were found in archived surveys as well. More. From Science: The claim Read More ›

Millennia ago,epicycles were introduced to astronomy to account for differences between theory and observation, thus saving the theory. Rob Sheldon writes to comment on a recent finding: New theory of secondary inflation expands options for avoiding an excess of dark matter. First, here’s the finding: Physicists suggest a smaller secondary inflationary period in the moments after the Big Bang could account for the abundance of the mysterious matter Standard cosmology — that is, the Big Bang Theory with its early period of exponential growth known as inflation — is the prevailing scientific model for our universe, in which the entirety of space and time ballooned out from a very hot, very dense point into a homogeneous and ever-expanding vastness. This Read More ›

Ross, here at : : How to Understand the Degree of Certainty in Key Discoveries An international team of astronomers has recently determined the rate of expansion for the universe based on studies of HII regions (star-forming gaseous nebulae) in 69 galaxies over a broad range of distances. This seems to be a straightforward scientific determination, but it is loaded with philosophical implications. Here’s why: Since the cosmic expansion rate measured is at least approximately constant, the inverse of that rate: (1) establishes that the universe had a beginning, (2) yields the amount of time that has transpired since the cosmic beginning, and (3) implies that a cosmic Initiator must exist to have set the cosmos in motion. Thus, if we Read More ›

Quasars. From Scientific American: A dozen quasars in the early universe appear to have shut down in just a few years, baffling astronomers … Last year Stephanie LaMassa from NASA Goddard Space Flight Center (then at Yale University) discovered the greatest change in luminosity ever detected in a quasar. She was digging through data from the Sloan Digital Sky Survey when she found that a quasar had dimmed in brightness by a factor of six in just 10 years. Its spectrum changed, too, from that of a classic quasar to a regular galaxy. … There is nothing controversial about the idea that active galactic nuclei can become inactive. What LaMassa and her colleagues doubted was that a quasar could go Read More ›