Survey finds no hint of dark matter near Solar System
In the largest survey of its kind to date, astronomers scouring the space around the Solar System for signs of dark matter — the hypothetical material believed to account for more than 80% of the mass in the Universe — have come up empty-handed.
If confirmed, the surprising result would upend a long-established consensus, researchers not involved in the study say. For decades, cosmic theories have relied on dark matter — which exerts gravitational pull but emits no light — to be the hidden scaffolding that explains how structure arose in the Universe, how galaxies formed and how the rapidly spinning Milky Way manages to keep from flying apart. Without dark matter, theorists say, the visible material in the Universe, such as stars and gas, would not have the heft to do the job alone.
The rest of the article explains how the research was conducted and what the scientific community thinks of the finding.
[NatureNews’] ace scoop-hungry reporter Ron Cowen late last week filed on a report, at the preprint server for physics-related news arXiv, that a large international team has gotten an image of a galaxy as it was when the universe was a mere 490 million years old.
Cowen writes the story well, and includes the enticing angle that if NASA’s Webb Telescope survives its budgetary excesses and goes into operation, its large IR mirror should offer a much better look at this galaxy – dubbed MACS1149-JD1.
American Scientist republished part of the article as part of its Science in the News section, which is a roundup of the most important and exciting science news pieces.
The article was mentioned here, on my Tumblr site, shortly after publication.
Infant galaxy offers tantalizing peek at early Universe
Astronomers are claiming a new benchmark in the quest to see the Universe’s first galaxies. By taking advantage of a rare cosmic zoom lens — where the gravity of a large mass magnifies light from objects in the distant background — a team of US and European researcher has spotted a galaxy so remote its light was emitted just 490 million years after the Big Bang, when the Universe was a mere 3.6% of its current age.
Read my entire article, which includes how existing and upcoming telescope capabilities could be used to investigate this galaxy further and what the find means for our understanding of the Universe’s number of galaxies.
My latest article is about new research that adds to the uncertainty of how the Moon was formed by looking at the Moon’s isotopic composition:
Question over theory of lunar formation
A chemical analysis of lunar rocks may force scientists to revise the leading theory for the Moon’s formation: that the satellite was born when a Mars-sized body smacked into the infant Earth some 4.5 billion years ago.
If that were the case, the Moon ought to bear the chemical signature of both Earth and its proposed ‘second’ parent. But a study published today inNature Geoscience1suggests that the Moon’s isotopic composition reflects only Earth’s contribution.
When we think of good vibrations, we usually don’t consider the vibrations made by stars. But a recent wave of work in asteroseismology is doing just that to break ground in our understanding of stellar structures. Due to the movement and changing temperatures of surface gas, a star pulses and vibrates. Those pulses and vibrations in the structure of the star provides insight about the star’s internal structure. From my Nature article Kepler’s surprise: The sounds of the stars:
…the vibrations penetrate deep into the stellar interior and become resonating tones that reveal the star’s size, composition and mass. So by watching for the characteristic fluctuations in brightness, says [University of Birmingham, UK, astrophysicist William] Chaplin, “we can literally build up a picture of what the inside of a star looks like”.
Better still, he adds, asteroseismologists are now hauling in the data wholesale. After years of being hampered by Earth’s turbulent atmosphere, which obscures the view of the Universe and has limited asteroseismology to about 20 of the brightest nearby stars, researchers have been astonished by the trove of information coming from a new generation of space observatories. Thanks to the French-led Convection, Rotation and Planetary Transits (COROT) space telescope, launched in 2006, and NASA’s Kepler space telescope, launched in 2009, they can now listen in on hundreds of stars at a time.
“We are in a golden age for the study of stellar structure and evolution,” says Hans Kjeldsen, an astronomer at Aarhus University in Denmark.