Science Scanner: Milky Way Bigger than Thought, Hydrothermal Activity on Saturn Moon, New Way to Fight Cavities & Gum Disease, Dwarf Galaxy Surprises Scientists

Posted March 12th, 2015 at 2:58 pm (UTC-5)
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A "rippled" Milky Way may be 50 percent larger than previously estimated (Rensselaer Polytechnic Institute)

A “rippled” Milky Way may be 50 percent larger than previously estimated (Rensselaer Polytechnic Institute)

Milky Way May Be Much Bigger than Thought

Our galaxy, the Milky Way may be much bigger than previously thought, up to 50 light-years further across, say researchers.

Researchers from the United States, China and the United Kingdom came to the conclusion after reviewing data gathered by the Sloan Digital Sky Survey (SDSS), an ongoing astronomy project that is creating comprehensive map of the universe.

Scientists say the increased size stems from the discovery of a bulging circle of stars located beyond what scientists have considered to be the known plane of the Milky Way.

The international team of scientists says, in a new study published was just published in the Astrophysical Journal, that their research shows the Milky Way’s galactic disk is actually shaped into several concentric ripples.

“In essence, what we found is that the disk of the Milky Way isn’t just a disk of stars in a flat plane — it’s corrugated,” said research leader Heidi Newberg, a professor of physics, applied physics, and astronomy in the Rensselaer School of Science in a university release. “As it radiates outward from the Sun, we see at least four ripples in the disk of the Milky Way. While we can only look at part of the galaxy with this data, we assume that this pattern is going to be found throughout the disk.”

The study’s lead author, Yan Xu, a scientist at the National Astronomical Observatories of China and a former visiting scientist at Rensselaer, says that the team’s findings indicate those features, originally recognized as rings, are really a part of the galactic disk.  The addition of this ring territory has extended the Milky Way’s known width from 100,000 light-years across to around 150,000 light-years.

Saturn’s icy moon Enceladus is spewing tiny silica grains, an indication hydrothermal activity is occurring in its ice-covered ocean. Such extreme environments are known to be suitable for life on Earth. (NASA/JPL)

Saturn’s icy moon Enceladus is spewing tiny silica grains, an indication hydrothermal activity is occurring in its ice-covered ocean. Such extreme environments are known to be suitable for life on Earth. (NASA/JPL)

Tiny Grains of Rock Provide Hints of Hydrothermal Activity on a Moon of Saturn

Microscopic grains of rock spotted near Saturn by NASA’s Cassini mission have provided scientists with some clear but tantalizing clues that hydrothermal activity is taking place within Enceladus one the ringed planet’s approximately 60 moons and moonlets.

The scientists believe that a heated and mineral-rich solution is being produced as the result of seawater getting into and reacting with its rocky crust.

Along with other observed geologic activity, such as geysers that have been found spewing jets of icy water high above its surface, this new finding only adds to the possibility that Enceladus could have the kind of environments that just might be hospitable for living organisms.

The scientists from the University of Colorado, Boulder made this discovery after conducting an all-encompassing four-year analysis of data from the Cassini spacecraft, which included laboratory experiments and computer modeling.

After examining the tiny bits of rock, the researchers think that they probably created whenever hot water – around 90° Celsius – that contains dissolved minerals from the moon’s rocky interior, moves up into and contacts much cooler water near the moon’s surface.

The research findings are outlined in a study that has just been published in the journal Nature.

 

Dentist conducts dental exam on a patient (US Army, 807th Medical Command)

Dentist conducts dental exam on a patient (US Army, 807th Medical Command)

Wonder Material May Make Cavities and Gum Disease a Thing of the Past

Chinese researchers believe graphene oxide could become an important tool in fighting dental diseases in the future.

According to the World Health Organization (WHO), oral health is essential to general health and quality of life.

Most dental health problems and diseases are caused by an overgrowth of bacteria in the mouth, which are often the result of poor dental hygiene.

Dentists today often prescribe antibiotics to get rid of all that harmful tooth decay and gum disease causing bacteria.  But, with the ongoing problem of antibiotic resistance scientists and medical/dental professionals need to seek alternatives to traditional antibiotics.

Studies conducted previously have revealed that the use of graphene oxide in biomedical applications shows great promise.   Scientists say that the material can prevent the growth of some strains of bacteria without causing much harm to health cells.

Zisheng Tang and his colleagues at Shanghai Jiao Tong University tested the material against three different kinds of bacteria that are known to cause tooth decay and gum disease.  The researchers found an application of graphene oxide successfully reduced the growth of the harmful bacteria by destroying its cell walls and membranes.

The researcher’s findings have been published in the American Chemical Society’s journal, Applied Materials & Interfaces.

 

This illustrates a region of the sky surrounding the newly discovered dwarf galaxy Reticulum 2. The image was generated using the authors’ search algorithm applied to Fermi gamma-ray data. (NASA/DOE/Fermi-LAT Collaboration/Geringer-Sameth & Walker/Carnegie-Mellon University/Koushiappas/Brown University)

This illustrates a region of the sky surrounding the newly discovered dwarf galaxy Reticulum 2. The image was generated using the authors’ search algorithm applied to Fermi gamma-ray data. (NASA/DOE/Fermi-LAT Collaboration/Geringer-Sameth & Walker/Carnegie-Mellon University/Koushiappas/Brown University)

Nearby Dwarf Galaxy Surprises Physicists

Gamma rays emanating from a dwarf galaxy may help in the discovery of dark matter.

The dwarf galaxy, which is called Reticulum 2, was found over the past few weeks within data collected by NASA’s Fermi Gamma-ray Space Telescope for an internationally collaborative experiment called the Dark Energy Survey.  The Dark Energy Survey is being conducted in order to understand the accelerated expansion of the universe.

The gamma rays left a team of physicists from Carnegie Mellon and Brown Universities in the US and Cambridge University in the United Kingdom surprised.

“In the search for dark matter, gamma rays from a dwarf galaxy have long been considered a very strong signature,” said team member Savvas Koushiappas, an assistant professor of physics at Brown University in a press release. “It seems like we may now be detecting such a thing for the first time.”

Reticulum 2 is one of closest dwarf galaxies to Earth that have been detected so far.  It’s about 98,000 light-years from Earth.

The team expressed caution that while their initial results are exciting, more research is needed to confirm a dark-matter origin.

The team’s findings have been submitted for publication in the journal Physical Review Letters.

Rick Pantaleo
Rick Pantaleo maintains the Science World blog and writes stories for VOA’s web and radio on a variety of science, technology and health topics. He also occasionally appears on various VOA programs to talk about the latest scientific news. Rick joined VOA in 1992 after a 20 year career in commercial broadcasting.

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