Quasars are among the brightest, oldest, most distant, and most powerful objects in the universe. Powered by massive black holes at the center of most known galaxies, quasars can emit enormous amounts of energy, up to a thousand times the total output of the hundreds of billions of stars in our entire Milky Way.
Heavens
By directing energy beams at tiny crystals found in a Martian meteorite, a Western University-led team of geologists has proved that the most common group of meteorites from Mars is almost 4 billion years younger than many scientists had believed – resolving a long-standing puzzle in Martian science and painting a much clearer picture of the Red Planet's evolution that can now be compared to that of habitable Earth.
Galaxies — systems like our own Milky Way that contain up to hundreds of billions of stars — are the basic building blocks of the cosmos. One ambitious goal of contemporary astronomy is to understand the ways in which galaxies grow and evolve, a key question being star formation: what determines the number of new stars that will form in a galaxy?
COLLEGE PARK, Md. -- Unlike humans, galaxies don't have an obesity problem. In fact there are far fewer galaxies at the most massive end of the galactic scale than expected and scientists have long sought to explain why. A new, UMD-led study published in the journal Nature suggests that one answer lies in a kind of feast and fast sequence through which large galaxies can keep their mass down.
A new study published in the journal Nature shows how vigorous star formation can turn the tables on a starburst galaxy by forcing hydrogen and other gases high into the surrounding galactic halo, leaving little fuel for the next generation of stars.
These new observations may help solve the mystery of the missing high-mass galaxies that theories predict should exist, but are conspicuously absent.
The fourth tropical depression of the Atlantic Ocean hurricane season was born west of the Cape Verde Islands in the Eastern Atlantic Ocean on July 24. NOAA's GOES-13 satellite provides continuous views of the Atlantic Ocean basin and captured an image of the newborn storm.
Efforts to cope with a global water crisis that already has left almost 800 million people without access to drinkable water -- and could engulf many more in the years ahead -- are the topic of the cover story in the current edition of Chemical & Engineering News. C&EN is the weekly newsmagazine of the American Chemical Society, the world's largest scientific society.
Purchasing designer handbags and shoes is a means for women to express their style, boost self-esteem, or even signal status. New University of Minnesota research suggests some women also seek these luxury items to prevent other women from stealing their man.
Washington, D.C.—Comets and meteorites contain clues to our solar system's earliest days. But some of the findings are puzzle pieces that don't seem to fit well together. A new set of theoretical models from Carnegie's Alan Boss shows how an outburst event in the Sun's formative years could explain some of this disparate evidence. His work could have implications for the hunt for habitable planets outside of our solar system. It is published by The Astrophysical Journal.
In a paper on decision making, human factors/ergonomics (HF/E) researchers found that choosing the best available emergency response could be improved by showing decision makers a depiction of the emergency decision space that allows them to compare their options visually. The researchers have developed the theory of option awareness (how people perceive and understand the desirability of available options), which can increase decision-making speed as well as accuracy, and confidence.
For the first time, scientists have documented an acceleration in the melt rate of permafrost, or ground ice, in a section of Antarctica where the ice had been considered stable. The melt rates are comparable with the Arctic, where accelerated melting of permafrost has become a regularly recurring phenomenon, and the change could offer a preview of melting permafrost in other parts of a warming Antarctic continent.
CORAL GABLES, FL (JULY 23, 2013) — Purple bacteria contain pigments that allow them to use sunlight as their source of energy, hence their color. Small as they are, these microbes can teach us a lot about life on Earth, because they have been around longer than most other organisms on the planet. University of Miami (UM) physicist Neil Johnson, who studies purple bacteria, recently found that these organisms can also survive in the presence of extreme alien light. The findings show that the way in which light is received by the bacteria can dictate the difference between life and death.
PROVIDENCE, R.I. [Brown University] — Valley networks branching across the Martian surface leave little doubt that water once flowed on the Red Planet. But where that ancient water came from — whether it bubbled up from underground or fell as rain or snow — is still debated by scientists. A new study by researchers at Brown University puts a new check mark in the precipitation column.
CORAL GABLES, FL (JULY 23, 2013) — Purple bacteria contain pigments that allow them to use sunlight as their source of energy, hence their color. Small as they are, these microbes can teach us a lot about life on Earth, because they have been around longer than most other organisms on the planet. University of Miami (UM) physicist Neil Johnson, who studies purple bacteria, recently found that these organisms can also survive in the presence of extreme alien light. The findings show that the way in which light is received by the bacteria can dictate the difference between life and death.
The potential impact of exposure to low levels of mercury on the developing brain – specifically by women consuming fish during pregnancy – has long been the source of concern and some have argued that the chemical may be responsible for behavioral disorders such as autism. However, a new study that draws upon more than 30 years of research in the Republic of Seychelles reports that there is no association between pre-natal mercury exposure and autism-like behaviors.