Monday
Galaxy Summary
Scientists wanted to look at the core elements of galaxies and their starting makeup. "Astronomers hoping to learn about the first stages of galaxy formation after the Big Bang use the chemical composition of stars to help them unravel the histories of the Milky Way and other nearby galaxies. Using these chemical analysis techniques, the team was able to categorize Segue 1’s uniquely ancient composition. Stars form from gas clouds, and their composition mirrors the chemical composition of the galactic gas from which they were born. Only a few million years after stars begin burning, the most massive stars explode in titanic blasts called supernovae. These explosions seed the nearby gas with heavy elements produced by the stars during their lifetimes. The very oldest stars consist almost entirely of the two lightest elements, hydrogen and helium, because they were born before ancient supernova explosions built up significant amounts of heavier elements."(Carnegie Institution for Science, Washington, D.C. | Published: Friday, May 02, 2014) The galaxy Segue 1 is an extremely old galaxy but is tiny and has probably not developed further because of its size. “The heaviest elements in this galaxy are at the lowest levels ever found,” said Anna Frebel of the Massachusetts Institute of Technology in Boston. “This gives us clues about what those first supernovae looked like.”(Carnegie Institution for Science, Washington, D.C. | Published: Friday, May 02, 2014) This "fossil" galaxy is paramount to further research into the formation of galaxies and supernovas.
"Nearby galaxy is a “fossil” from the early universe"
"In contrast to all other galaxies, the new analysis shows that Segue 1’s star formation ended at what would ordinarily be an early stage of a galaxy’s development.
By Carnegie Institution for Science, Washington, D.C. | Published: Friday, May 02, 2014
New work from a team of scientists, including Carnegie’s Josh Simon, analyzed the chemical elements in the faintest known galaxy, Segue 1, and determined that it is effectively a fossil galaxy left over from the early universe.
Astronomers hoping to learn about the first stages of galaxy formation after the Big Bang use the chemical composition of stars to help them unravel the histories of the Milky Way and other nearby galaxies. Using these chemical analysis techniques, the team was able to categorize Segue 1’s uniquely ancient composition.
Stars form from gas clouds, and their composition mirrors the chemical composition of the galactic gas from which they were born. Only a few million years after stars begin burning, the most massive stars explode in titanic blasts called supernovae. These explosions seed the nearby gas with heavy elements produced by the stars during their lifetimes. The very oldest stars consist almost entirely of the two lightest elements, hydrogen and helium, because they were born before ancient supernova explosions built up significant amounts of heavier elements.
In most galaxies, this process is cyclical, with each generation of stars contributing more heavy elements to the raw material from which the next set of stars will be born. But not in Segue 1. In contrast to all other galaxies, the new analysis shows that Segue 1’s star formation ended at what would ordinarily be an early stage of a galaxy’s development. Segue 1 likely failed to progress further because of its unusually tiny size.
“Our work suggests that Segue 1 is the least chemically evolved galaxy known,” Simon said. “After the initial few supernova explosions, it appears that only a single generation of new stars were formed, and then for the last 13 billion years the galaxy has not been creating stars.”
Because it has stayed in the same state for so long, Segue 1 offers unique information about the conditions in the universe shortly after the Big Bang. Other galaxies have undergone multiple supernova explosions since their formation. The first supernovae to blow up, from the most massive stars, produce elements like magnesium, silicon, and calcium. Later explosions of smaller stars primarily make iron. Segue 1’s uniquely low iron abundance relative to other elements shows that its star formation must have stopped before any of the iron-forming supernovae occurred.
This truncated evolution means that the products of the first explosions in Segue 1 have been preserved. Intriguingly, very heavy elements like barium and strontium are nearly absent from Segue 1’s stars.
“The heaviest elements in this galaxy are at the lowest levels ever found,” said Anna Frebel of the Massachusetts Institute of Technology in Boston. “This gives us clues about what those first supernovae looked like.”
Studying individual stars in dwarf galaxies can be difficult, and Segue 1, which orbits our Milky Way, is particularly puny, containing only about a thousand stars. Just seven stars in the entire galaxy are in the red-giant phase of their lives, making them bright enough for modern telescopes to detect the features astronomers use to measure the abundance of each chemical element. Three of the seven red giants have heavy element abundances more than 3,000 times lower than that of the Sun, highlighting the primitive nature of the galaxy.
“Having found such a fossil galaxy is of enormous importance to astronomy because it provides a new window into the first galaxies,” Frebel said.
The team used one of Carnegie’s 6.5-meter Magellan telescopes in Chile to observe five of the Segue 1 stars, while one was studied with the 10-meter Keck I Telescope in Hawaii. The final star was identified and measured by a competing team using the European Southern Observatory’s 8.2-meter Very Large Telescope, also in Chile."(http://www.astronomy.com/news/2014/05/nearby-galaxy-is-a-fossil-from-the-early-universe)
Key Nutrients Summary
Scientists have found a key nutrient for human existence in space. Astronomers and scientists think radiation-blasted powered the chemical reaction used to make B3. B3 is essential to human health and is not made in the body. It can only be obtained from outside sources, i.e. food. Scientists have found this and other essential vitamins in meteorites.
Key Nutrients
"An essential nutrient for life on Earth also cooks up in space, a new study finds.
While scientists aren't yet sure of the exact recipe, they think radiation-blasted ice powered the chemical reactions that produced vitamin B3, or niacin, early in the solar system's history. A stew of dust and ice created key molecules for life in this planetary kitchen, which all later clumped into asteroids and comets, suggests the new study, published April 13 in the journal Geochimica et Cosmochimica Acta.
Some researchers think impacts on early Earth could have delivered chemicals essential for life, such as amino acids and vitamins like niacin. Today, niacin isn't made by the human body, and must be consumed in the diet.
"Vitamin B3 is essential to metabolism and likely very ancient in origin," lead study author Karen Smith of Pennsylvania State University said in a statement.
Smith and her co-authors discovered vitamin B3 in eight carbon-rich meteorites. (When fragments of an asteroid fall to Earth, they're called meteorites.) The meteorites are all CM-2 carbonaceous chondrites, one of the most common meteorite types found on Earth.
The meteorite's vitamin B3 levels ranged from 30 to 600 parts per billion, the study reports. Related molecules discovered in the meteorites include pyridine carboxylic acids and pyridine dicarboxylic acids.
The amount of vitamin B3 in the meteorites was linked to how much their parentasteroids were altered by water, Smith said. "We discovered a pattern — less vitamin B3 was found in meteorites that came from asteroids that were more altered by liquid water," she said. Several chemical and mineral traces in meteorites show how much an asteroid was altered by water.
The researchers also tested their theory of how vitamin B3 may form in space with laboratory experiments. "We showed that the synthesis of vitamin B3 might be possible on ice grains," Smith said.
Earlier research has also shown vitamin B3 can be produced non-biologically on Earth, Smith said. The team plans further experiments to explore how the vitamin can form on ice grains in space." (http://www.huffingtonpost.com/2014/04/21/meteorites-vitamin-b3-nutrient-space_n_5183585.html?utm_hp_ref=astronomy)
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While scientists aren't yet sure of the exact recipe, they think radiation-blasted ice powered the chemical reactions that produced vitamin B3, or niacin, early in the solar system's history. A stew of dust and ice created key molecules for life in this planetary kitchen, which all later clumped into asteroids and comets, suggests the new study, published April 13 in the journal Geochimica et Cosmochimica Acta.
Some researchers think impacts on early Earth could have delivered chemicals essential for life, such as amino acids and vitamins like niacin. Today, niacin isn't made by the human body, and must be consumed in the diet.
"Vitamin B3 is essential to metabolism and likely very ancient in origin," lead study author Karen Smith of Pennsylvania State University said in a statement.
Smith and her co-authors discovered vitamin B3 in eight carbon-rich meteorites. (When fragments of an asteroid fall to Earth, they're called meteorites.) The meteorites are all CM-2 carbonaceous chondrites, one of the most common meteorite types found on Earth.
The meteorite's vitamin B3 levels ranged from 30 to 600 parts per billion, the study reports. Related molecules discovered in the meteorites include pyridine carboxylic acids and pyridine dicarboxylic acids.
The amount of vitamin B3 in the meteorites was linked to how much their parentasteroids were altered by water, Smith said. "We discovered a pattern — less vitamin B3 was found in meteorites that came from asteroids that were more altered by liquid water," she said. Several chemical and mineral traces in meteorites show how much an asteroid was altered by water.
The researchers also tested their theory of how vitamin B3 may form in space with laboratory experiments. "We showed that the synthesis of vitamin B3 might be possible on ice grains," Smith said.
Earlier research has also shown vitamin B3 can be produced non-biologically on Earth, Smith said. The team plans further experiments to explore how the vitamin can form on ice grains in space." (http://www.huffingtonpost.com/2014/04/21/meteorites-vitamin-b3-nutrient-space_n_5183585.html?utm_hp_ref=astronomy)
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Tuesday
Habitable Summary
Scientists have found a planet about the size of Earth in, what we consider to be, a habitable zone. This means that life could possibly exist in this zone. The planet's size is known but not much else. However, due to some previous research, scientists think the planet is rocky and mountainous. The planet is named Kepler-186f and it is found in the constellation Cygnus. This planet orbits a star that is much smaller than our sun, it is a red dwarf. Scientists will continue looking for Earth twins and just because a planet is in the habitable zone does not mean it is habitable. Maybe we need to look elsewhere.
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