Our entire understanding of the Universe is based on knowing the distances to other galaxies, yet this seemingly-simple question turns out to be fiendishly difficult to answer. The best answer came more than 100 years ago from an astronomer who was mostly unrecognized in her time—and today, another astronomer has used Sloan Digital Sky Survey (SDSS) data to make those distance measurements more precise than ever. (more…)
Die Vergangenheit ist „fix“ und unabänderlich, die Zukunft aber „offen“ und beeinflussbar. Seit Einstein wissen wir aber, dass es keine eindeutig definierte Gegenwart als „Trennlinie“ zwischen Vergangenheit und Zukunft gibt. Den scheinbaren Widerspruch zwischen Alltagserleben und Relativitätstheorie will der Philosoph Daniel Saudek lösen.(more…)
ANN ARBOR — Up to half of the water on Earth is likely older than the solar system itself, University of Michigan astronomers theorize.
The researchers’ work, published in the current issue of Science, helps to settle a debate about just how far back in galactic history our planet and our solar system’s water formed. Were the molecules in comet ices and terrestrial oceans born with the system itself—in the planet-forming disk of dust and gas that circled the young sun 4.6 billion years ago? Or did the water originate even earlier—in the cold, ancient molecular cloud that spawned the sun and that planet-forming disk? (more…)
ANN ARBOR — In findings that help astrophysicists understand our corner of the galaxy, an international research team has shown that the soft X-ray glow blanketing the sky comes from both inside and outside the solar system.
The source of this “diffuse X-ray background” has been debated for the past 50 years. Does it originate from the solar wind colliding with interplanetary gases within our solar system? Or is it born further away, in the “local hot bubble” of gas that a supernova is believed to have left in our galactic neighborhood about 10 million years ago? (more…)
Thanks to NASA’s Kepler and Spitzer Space Telescopes, scientists have made the most precise measurement ever of the radius of a planet outside our solar system. The size of the exoplanet, dubbed Kepler-93b, is now known to an uncertainty of just 74 miles (119 kilometers) on either side of the planetary body.
The findings confirm Kepler-93b as a “super-Earth” that is about one-and-a-half times the size of our planet. Although super-Earths are common in the galaxy, none exist in our solar system. Exoplanets like Kepler-93b are therefore our only laboratories to study this major class of planet. (more…)
Speeding at 1 Million mph, It Probes Black Hole and Dark Matter
A University of Utah-led team discovered a “hypervelocity star” that is the closest, second-brightest and among the largest of 20 found so far. Speeding at more than 1 million mph, the star may provide clues about the supermassive black hole at the center of our Milky Way and the halo of mysterious “dark matter” surrounding the galaxy, astronomers say. (more…)
AUSTIN, Texas — A team of researchers led by astronomer Ivan Ramirez of The University of Texas at Austin has identified the first “sibling” of the sun — a star almost certainly born from the same cloud of gas and dust as our star. Ramirez’s methods will help astronomers find other solar siblings, which could lead to an understanding of how and where our sun formed, and how our solar system became hospitable for life. The work appears in the June 1 issue of The Astrophysical Journal.
“We want to know where we were born,” Ramirez said. “If we can figure out in what part of the galaxy the sun formed, we can constrain conditions on the early solar system. That could help us understand why we are here.” (more…)
Life took root more than four billion years ago on our nascent Earth, a wetter and harsher place than now, bathed in sizzling ultraviolet rays. What started out as simple cells ultimately transformed into slime molds, frogs, elephants, humans and the rest of our planet’s living kingdoms. How did it all begin?
A new study from researchers at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., and the Icy Worlds team at NASA’s Astrobiology Institute, based at NASA’s Ames Research Center in Moffett Field, Calif., describes how electrical energy naturally produced at the sea floor might have given rise to life. While the scientists had already proposed this hypothesis — called “submarine alkaline hydrothermal emergence of life” — the new report assembles decades of field, laboratory and theoretical research into a grand, unified picture. (more…)
