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Hubble --"Largest Moon in Our Solar System Harbors a Buried Ocean 100 Kilometers Deep" (Weekend Feature)

Hubble --"Largest Moon in Our Solar System Harbors a Buried Ocean 100 Kilometers Deep" (Weekend Feature)

www.dailygalaxy.com

This past March, NASA's Hubble Space Telescope revealed the best evidence yet for an underground saltwater ocean on Ganymede, Jupiter's largest moon. The subterranean ocean is thought to have more water than all the water on Earth's surface. Identifying liquid water is crucial in the search for habitable worlds beyond Earth and for the search for life, as we know it.

"This discovery marks a significant milestone, highlighting what only Hubble can accomplish," said John Grunsfeld, assistant administrator of NASA's Science Mission Directorate at NASA Headquarters. "In its 25 years in orbit, Hubble has made many scientific discoveries in our own solar system. A deep ocean under the icy crust of Ganymede opens up further exciting possibilities for life beyond Earth."

Ganymede is the largest moon in our solar system and the only moon with its own magnetic field. The magnetic field causes aurorae, which are ribbons of glowing, hot electrified gas, in regions circling the north and south poles of the moon. Because Ganymede is close to Jupiter, it is also embedded in Jupiter's magnetic field. When Jupiter's magnetic field changes, the aurorae on Ganymede also change, "rocking" back and forth

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New Dark-Matter Discovery: "Nine Concentrations Each the Mass of a Galaxy Cluster"

New Dark-Matter Discovery: "Nine Concentrations Each the Mass of a Galaxy Cluster"

www.dailygalaxy.com

Researchers from the National Astronomical Observatory of Japan (NAOJ), the University of Tokyo and other institutions have begun a wide-area survey of the distribution of dark matter in the universe using Hyper Suprime-Cam, a new wide-field camera installed on the Subaru Telescope in Hawai'i. Initial results from observations covering an area of 2.3 square degrees on the sky toward the constellation Cancer revealed nine large concentrations of dark matter, each the mass of a galaxy cluster.

Surveying how dark matter is distributed and how the distribution changes over time is essential to understanding the role of dark energy that controls the expansion of the universe. These first results demonstrate that astronomers now have the techniques and tools to understand dark energy. The next step is for the research team to expand the survey to cover a thousand square degrees on the sky, and thereby unravel the mystery of dark energy and the expansion of the universe.
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Galaxias ultradifusas en el cúmulo de Coma con un 99% de su masa en forma de materia oscura | Astrofísica | La Ciencia de la Mula Francis

Galaxias ultradifusas en el cúmulo de Coma con un 99% de su masa en forma de materia oscura | Astrofísica | La Ciencia de la Mula Francis

francis.naukas.com

En el Cúmulo de Coma (Abell 1656) se han descubierto 854 galaxias ultradifusas gracias al Telescopio Subaru en Hawaii. Muchas (332) tienen una masa similar a la Vía Láctea, pero muy pocas estrellas, sólo un 0,1% de las estrellas de nuestra galaxia. Por tanto, más del 99% de la masa de estas galaxias ultradifusas debe ser materia oscura. Un resultado realmente sorprendente: galaxias dominadas por la materia oscura. Y gran reto para las teorías de gravedad modificada tipo MOND que difícilmente podrán explicar estas observaciones.

El artículo es Jin Koda et al., “Approximately A Thousand Ultra Diffuse Galaxies in the Coma cluster,” The Astrophysical Journal Letters 807: L2, 2015, doi: 10.1088/2041-8205/807/1/L2, arXiv:1506.01712 [astro-ph.GA].

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Venus and Jupiter Put on a Celestial Show This Month

Venus and Jupiter Put on a Celestial Show This Month

www.space.com

f you've been watching the western sky just after sunset lately, you will have noticed two bright objects, gradually drawing closer.

These are the two brightest planets, Venus and Jupiter. Venus is the brighter of the two, currently magnitude -4.6 on the upside-down brightness scale astronomers use. It will get slightly brighter over the next 10 days, reaching greatest brilliance on July 10 at magnitude -4.7.

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Como de increíblemente inmenso es el Universo según el telescopio espacial Hubble

Como de increíblemente inmenso es el Universo según el telescopio espacial Hubble

lacienciaysusdemonios.com

cosmos-universo-estrellasEn este video se muestra uno de los fascinantes experimentos que ha llevado a cabo el telescopio espacial Hubble a lo largo de su ya dilatada historia. Al enfocar hacia una diminuta región, oscura y en principio sin ninguna estrella se descubrió una gran complejidad estelar que permite hacerse una idea de lo inmensamente enorme y lo profundamente desconocido que es el Universo en que vivimos.

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Dwarf Planet Ceres Mysterious Bright Spots Baffle NASA

Dwarf Planet Ceres Mysterious Bright Spots Baffle NASA

www.dailygalaxy.com

The closer we get to Ceres, the more intriguing the distant dwarf planet becomes. New images of Ceres from NASA's Dawn spacecraft provide more clues about its mysterious bright spots, and also reveal a pyramid-shaped peak towering over a relatively flat landscape.

"The surface of Ceres has revealed many interesting and unique features. For example, icy moons in the outer solar system have craters with central pits, but on Ceres central pits in large craters are much more common. These and other features will allow us to understand the inner structure of Ceres that we cannot sense directly," said Carol Raymond, deputy principal investigator for the Dawn mission, based at NASA's Jet Propulsion Laboratory in Pasadena, California.

Dawn has been studying the dwarf planet in detail from its second mapping orbit, which is 2,700 miles (4,400 kilometers) above Ceres. A new view of its intriguing bright spots, located in a crater about 55 miles (90 kilometers) across, shows even more small spots in the crater than were previously visible.

At least eight spots can be seen next to the largest bright area, which scientists think is approximately 6 miles (9 kilometers) wide. A highly reflective material is responsible for these spots -- ice and salt are leading possibilities, but scientists are considering other options, too.

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Kepler Mission --"Discovers 33 Stars Over 11 Billion Years Old With Earth-Like Planets"

Kepler Mission --"Discovers 33 Stars Over 11 Billion Years Old With Earth-Like Planets"

www.dailygalaxy.com

One of the biggest questions in astrophysics is: does life exists beyond earth? To even begin answering this, we need to know how many planets like ours exist out there, and when they formed. However determining ages of stars (and thus of their orbiting planets) is extremely difficult; precise ages are only available for a handful of host stars thanks to asteroseismic observations made with the Kepler satellite.

A new study of 33 Kepler stars with solar-like oscillations to be published in Monthly Notices of the Royal Astronomical Society. The 33 Kepler stars have been selected for their solar like oscillations and a set of basic parameters have been determined with high precision showing that stars even older than 11 billion years have Earth-like planets.

According to lead author of the article Victor Silva Aguirre from the Stellar Astrophysics Centre at Aarhus University, Denmark: " Our team has determined ages for individual host stars before with similar levels of accuracy, but this constitutes the best characterised set of exoplanet host stars currently available."

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Quantum Origins of the Universe --"Seeded the Early Galaxies and Clusters " (Weekend Feature)

Quantum Origins of the Universe --"Seeded the Early Galaxies and Clusters " (Weekend Feature)

www.dailygalaxy.com

The Planck data confirm the basic predictions that quantum fluctuations are at the origin of all structures in the Universe," said Jean-Loup Puget, Principal Investigator for the HFI-instrument on the Planck satellite. Viatcheslav Mukhanov, a cosmologist at Ludwig-Maximilians-Universitaet (LMU) in Munich, an expert in the field of Theoretical Cosmology., who first published his model in 1981 and joined the Physics Faculty at LMU in 1997, said: "I couldn't hope for a better verification of my theory."

Data from the Planck telescope have confirmed beyond any reasonable doubt a theory of the quantum origin of structure in the Universe. What exactly happened after the Universe was born? Why did stars, planets and huge galaxies form? These are the questions that concern Mukhanov. He has used the notion of so-called quantum fluctuations to construct a theory that provides a precise picture of the crucial initial phase of the evolution of our Universe: Without the minimal variations in energy density that result from the tiny but unavoidable quantum fluctuations, one cannot account for the formation of stars, planets and galaxies that characterize the Universe we observe today.
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Francis en #rosavientos: El agujero negro más brillante en los últimos 26 años | Astrofísica | La Ciencia de la Mula Francis

Francis en #rosavientos: El agujero negro más brillante en los últimos 26 años | Astrofísica | La Ciencia de la Mula Francis

francis.naukas.com
Los agujeros negros rodeados de un disco de acreción de materia emiten luz de forma muy intensa a ráfagas separadas por periodos de reposo. El agujero negro V404 Cygni (en la Costelación del Cisne) ha emitido un violento estallido de rayos X el pasado 15 de junio de 2015. Según los astrónomos este tipo de eventos “solo se ven una vez en la vida” y, de hecho, V404 Cygni ha estado inactivo durante 25 años. El fenómeno está ocasionando un enorme revuelo entre astrónomos profesionales y aficionados. Ahora mismo es la fuente de rayos X más intensa de nuestro cielo. Se está obteniendo mucha información que dará lugar a investigaciones durante muchos años.
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Spiral Galaxy Arms --"Incubate Rocky Terrestrial Planets"

Spiral Galaxy Arms --"Incubate Rocky Terrestrial Planets"

www.dailygalaxy.com

revailing theory of how rocky planets formed in our own Solar System, as well as in others. The snag he's untangling: how dust grains in the matter orbiting a young protostar avoid getting dragged into the star before they accumulate into bodies large enough that their own gravity allows them to rapidly attract enough material to grow into planets.

In the early stages of their formation, stars are surrounded by rotating disks of gas and dust. The dust grains in the disk collide and aggregate to form pebbles, which grow into boulders, and so on increasing in size through planetesimals, planetary embryos, and finally rocky terrestrial planets. But there are some difficult outstanding questions raised by this theory. One of these is that the pressure gradient of the gas in the disk would create a headwind that would spiral the pebbles and boulders inward toward the young protostar, where they would be destroyed.
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NASA: "Rejuvenated Planets Can Survive a Stars' Red-Giant Death Cycle"

NASA: "Rejuvenated Planets Can Survive a Stars' Red-Giant Death Cycle"

www.dailygalaxy.com

For a planet, this would be like a day at the spa. After years of growing old, a massive planet could, in theory, brighten up with a radiant, youthful glow. Rejuvenated planets, as they are nicknamed, are only hypothetical. But new research from NASA's Spitzer Space Telescope has identified one such candidate, seemingly looking billions of years younger than its actual age.

"When planets are young, they still glow with infrared light from their formation," said Michael Jura of UCLA, coauthor of a new paper on the results in the June 10 issue of the Astrophysical Journal Letters. "But as they get older and cooler, you can't see them anymore. Rejuvenated planets would be visible again."
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Carbon Glow of Galaxies At 'Cosmic Dawn' Observed

Carbon Glow of Galaxies At 'Cosmic Dawn' Observed

www.dailygalaxy.com

When galaxies first assembled, during a period often referred to as 'Cosmic Dawn,' most of the space between the stars was filled with a mixture of hydrogen and helium produced in the Big Bang. As subsequent generations of massive stars ended their brief but brilliant lives as supernovas, they seeded the interstellar medium with a fine dust of heavy elements, mostly carbon, silicon, and oxygen, which are forged in their nuclear furnaces.

Astronomers study the elements scattered between the stars to learn about the internal workings of galaxies, their motion and chemistry. To date, however, attempts to detect the telltale radio signature of carbon in the very early Universe have been thwarted, perhaps -- as some have speculated -- by the need to allow a few billion years more for stars to manufacture sufficient quantities to be observed across such vast cosmic distances.
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'Lost-in-Space' Galaxy --"Observed at the Edge of the Void"

'Lost-in-Space' Galaxy --"Observed at the Edge of the Void"

www.dailygalaxy.com

Although the Universe may seem spacious most galaxies are clumped together in groups or clusters and a neighbour is never far away. But this galaxy, known as NGC 6503, has found itself in a lonely position, shown here at the edge of a strangely empty patch of space called the Local Void, a patch of space thought to be about 150 million light-years across that seems to be curiously devoid of galaxies. Astronomers using Hubble discovered that the emptiness of this region has quite an effect on the space around us -- the Milky Way is being strongly pulled away from it by the gentle but relentless tug of other nearby galaxies.

NGC 6503 is only some 18 million light-years away from us in the constellation of Draco (The Dragon), making it one of the closest neighbours from our Local Group. It spans some 30 000 light-years, about a third of the size of the Milky Way. The galaxy's lonely location led stargazer Stephen James O'Meara to dub it the "Lost-In-Space galaxy" in his 2007 book Hidden Treasures [1].
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Astrofísica y Física: Nuevas imágenes de los puntos brillantes de Ceres

Astrofísica y Física: Nuevas imágenes de los puntos brillantes de Ceres

www.astrofisicayfisica.com
Las nuevas imágenes del planeta enano Ceres, enviadas por la nave espacial Dawn de la NASA, muestran una superficie llena de cráteres con gran detalle. Estas son algunas de las primeras instantáneas de la segunda órbita de mapeo de Dawn, que se encuentra a unos 4.400 kilómetros por encima de Ceres.

La región en la que se observan los puntos más brillantes es un cráter de 90 kilómetros de diámetro. Las manchas se componen de muchos puntos brillantes individuales de diferentes tamaños, con un cúmulo central. Hasta ahora, los científicos no han encontrado ninguna explicación definitiva para su origen o composición.
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Supermassive Black-Hole Eruptions --"Shape the Cosmic Landscape"

Supermassive Black-Hole Eruptions --"Shape the Cosmic Landscape"

www.dailygalaxy.com

Astronomers have used NASA’s Chandra X-ray Observatory to show that, multiple eruptions from a supermassive black hole over 50 million years have rearranged the cosmic landscape at the center of a group of galaxies. Scientists discovered this history of black hole eruptions by studying NGC 5813, a group of galaxies about 105 million light years from Earth. These Chandra observations are the longest ever obtained of a galaxy group, lasting for just over a week. The Chandra data are shown in this new composite image where the X-rays from Chandra (purple) have been combined with visible light data (red, green and blue).

Galaxy groups are like their larger cousins, galaxy clusters, but instead of containing hundreds or even thousands of galaxies like clusters do, galaxy groups are typically comprised of 50 or fewer galaxies. Like galaxy clusters, groups of galaxies are enveloped by giant amounts of hot gas that emit X-rays.
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Astrofísica y Física: Estrellas de neutrones: formación y definición

www.astrofisicayfisica.com
¿Quieres saber de una forma sencilla qué es una estrella de neutrones? José Pons y Antonio Miralles te acercan en esta entrevista a estos objetos exóticos.
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Today's 'Galaxy' Insight --The Origin of Spacetime

Today's 'Galaxy' Insight --The Origin of Spacetime

www.dailygalaxy.com
“Henceforth, space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent reality.”
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Hermann Minkowski
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¿La Tierra gira cada vez más lentamente? Sí, y antes los años tenían 400 días

¿La Tierra gira cada vez más lentamente? Sí, y antes los años tenían 400 días

www.xatakaciencia.com

Una de las imágenes más anticientíficas que recuerdo de la historia del cine es la que ocurre en una película de Supermán, en la que el hombre de acero empieza a dar vueltas alrededor de la Tierra a gran velocidad para invertir su rotación: primero la detiene, y luego la invierte, lo que supone que el tiempo también retrocede y así puede salvar a Louis Lane de una muerte segura.

Detener la Tierra supondría un cataclismo para la humanidad, y probablemente no haría retroceder las agujas de nuestros relojes. Sin embargo, sin la necesidad de Supermán, nuestro planeta sí que se está desacelerando progresivamente.

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Charlas DC14: Los pequeñines del Sistema Solar | Hablando de Ciencia | Artículos

www.hablandodeciencia.com
Dentro de la sesión de Física, Pablo Santos Sanz del Instituto de Astrofísica de Andalucía impartió una charla con título “Los pequeñines del Sistema Solar”
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What Is The Difference Between Asteroids and Meteorites?

What Is The Difference Between Asteroids and Meteorites?

www.universetoday.com
Asteroids, meteors, and meteorites … It might be fair to say these rocks from space inspire both wonder and fear among us Earthlings. But knowing a bit more about each of them and how they differ may eliminate some potential misgivings. While all these rocks originate from space, they have different names depending their location — i.e. whether they are hurtling through space or hurtling through the atmosphere and impacting Earth’s surface.
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Vega 0.0. Astronomía y Universo: Destellos desde Vega: Los exoplanetas similares a la Tierra podrían ser más frecuentes alrededor de estrellas similares al Sol

Vega 0.0. Astronomía y Universo: Destellos desde Vega: Los exoplanetas similares a la Tierra podrían ser más frecuentes alrededor de estrellas similares al Sol

www.vega00.com
Un simulación realizada por Shigeru Ida (Tokyo Institute of Technology) y Feng Tian (Universidad de Tsinghua) apunta a que los exoplanetas similares a la Tierra podrían ser más frecuentes alrededor de estrellas similares al Sol. Al menos en un aspecto, la cantidad de agua que existe en su superficie. Actualmente el principal objetivo para buscar exoplanetas en la zona de habitabilidad son las estrellas enanas rojas, de tipo espectral M, cuya masa es inferior a la mitad de la solar. Esto se debe a que algunos estudios apuntan a que es más fácil encontrar exoplanetas orbitándolas en la zona de habitabilidad de la estrella que en el caso de estrellas de tipo espectral G, similares al Sol.

Según la nueva propuesta (publicada en Nature Geoscience) en el caso de las estrellas de tipo G, su luminosidad durante la etapa pre-secuencia principal es casi constante. Sin embargo en el caso de las estrellas de tipo M y durante esta etapa, la luminosidad decrece en más de un orden de magnitud. Esto causaría que en esta etapa temprana, aquellos exoplanetas similares en cantidad de agua a la Tierra, perdieran gran cantidad de ésta.
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Circular Orbits a Sign of Habitability? --"The Norm for 74 Earth-Sized Planets"

Circular Orbits a Sign of Habitability? --"The Norm for 74 Earth-Sized Planets"

www.dailygalaxy.com


The system Kepler-444 shown above formed when the Milky Way galaxy was a youthful two billion years old. The planets were detected from the dimming that occurs when they transit the disc of their parent star, as shown in this artist's conception. Observations of 74 Earth-sized planets around distant stars may narrow field of habitable candidates. Viewed from above, our solar system's planetary orbits around the sun resemble rings around a bulls-eye. Each planet, including Earth, keeps to a roughly circular path, always maintaining the same distance from the sun.

For decades, astronomers have wondered whether the solar system's circular orbits might be a rarity in our universe. Now a new analysis suggests that such orbital regularity is instead the norm, at least for systems with planets as small as Earth.

In a paper published in the Astrophysical Journal, researchers from MIT and Aarhus University in Denmark report that 74 exoplanets, located hundreds of light-years away, orbit their respective stars in circular patterns, much like the planets of our solar syste

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How do galaxies die?

How do galaxies die?

phys.org

Everything eventually dies, even galaxies. So how does that happen?

Time to come to grips with our galactic mortality. Not as puny flesh beings, or as a speck of rock, or even the relatively unassuming ball of plasma we orbit.

Today we're going to ponder the lifespan of the galaxy we inhabit, the Milky Way. If we look at a galaxy as a collection of stars, some are like our Sun, and others aren't.

The Sun consumes fuel, converting hydrogen into helium through fusion. It's been around for 5 billion years, and will probably last for another 5 before it bloats up as a red giant, sheds its outer layers and compresses down into a white dwarf, cooling down until it's the background temperature of the universe.

So if a galaxy like the Milky Way is just a collection of stars, isn't that it? Doesn't a galaxy die when its last star dies?

But you already know a galaxy is more than just stars. There's also vast clouds of gas and dust. Some of it is primordial hydrogen left from the formation of the universe 13.8 billion years ago

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Astrofísica y Física: Cassini visita al Bob Esponja del Sistema Solar

Astrofísica y Física: Cassini visita al Bob Esponja del Sistema Solar

www.astrofisicayfisica.com
Ayer, 31 de mayo, la sonda espacial Cassini nos envió estas maravillosas imágenes de Hyperion, la luna de Saturno apodada "Bob Esponja" por su aspecto esponjoso. Cuando las imágenes estén calibradas se apreciarán mucho mejor los detalles de esta pequeña luna.

Orbita a una distancia media de Saturno de 1.481.000 km, realizando una vuelta en poco más de veintiún días y seis horas. De forma relativamente irregular, tiene un diámetro de alrededor de 300 km y una masa mil veces inferior a la de nuestra Luna.

Hyperión es uno de los cuerpos con forma irregular más grandes del sistema solar. El mayor cráter de impacto tiene aproximadamente 120 km de diámetro y 10 km de profundidad. Una posible explicación de su forma irregular es que Hyperión es un fragmento de un satélite previo más grande que fue parcialmente destruido por un gran impacto hace mucho tiempo atrás, un evento que se ha relacionado con el oscurecimiento parcial de Japeto.
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Young Solar System Observed Around a Nearby Star

Young Solar System Observed Around a Nearby Star

www.dailygalaxy.com


The discovery of the bright ring of orbiting the star HD 115600 changes everything, said Thayne Currie of the Subaru Telescope, a Subaru Project Fellow research astronomer. "It's kind of like looking at our solar system when it was a toddler."

An international team led by Currie using the Gemini South telescope, has discovered a young planetary system that shares remarkable similarities to our own early solar system. Their images reveal a ring-like disk of debris surrounding a Sun-like star, in a birth environment similar to the Sun's. The disk appears to be sculpted by at least one unseen solar system-like planet, is roughly the same size as our solar system's Edgeworth-Kuiper Belt (commonly called the Kuiper Belt), and may contain dust and icy particles. This work provides a valuable key to understanding the early formation of the Sun and planets.
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Measuring the size of a quasar

briankoberlein.com
Quasars are very bright objects that are generally billions of light years away. We now know that they are a kind of active galactic nuclei (AGN) and are powered by supermassive black holes in the centers of galaxies. We know this in part because they emanate from within galaxies, and their energy comes from a region only a few light years across. But how do we know the size of something from billions of light years away?
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Tchouri, la comète de Rosetta, serait née d’une collision

Tchouri, la comète de Rosetta, serait née d’une collision

www.futura-sciences.com
La comète 67P/Churyumov-Gerasimenko, observée par la sonde Rosetta, exhibe une forme binaire, composée de deux lobes. Selon deux chercheurs, cette forme serait liée à la collision puis la fusion de deux corps en un seul. Leur étude propose un scénario s'appuyant sur des simulations numériques en 3D.
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Jupiter's Moons --"Hint at Life on Alien Moons of Gas Giants"

Jupiter's Moons --"Hint at Life on Alien Moons of Gas Giants"

www.dailygalaxy.com

Researchers who have modeled planetary systems far beyond our own solar system have found that massive moons larger than Mars might be the best bet. Using data from our solar system and observations of huge planets far beyond the visual range of any telescope, astrophysicists René Heller and Ralph Pudritz of McMaster University have shown that some moons of those planets could be habitable.

Their findings, presented in two papers in the journals Astronomy and Astrophysics and The Astrophysical Journal, suggest that some moons of exoplanets -- planets beyond our solar system -- are the right size, in the right position and have sufficient water to support life.

"We could be just a few decades from proving if there is life elsewhere," says Heller, a post-doctoral fellow at McMaster's Origins Institute who worked with Pudritz, a professor of physics and astronomy and director of the Origins Institute. "For all this time, we have been looking on other planets, when the answer could be on a moon."

Exoplanets are being counted in the thousands since the development of new, non-visual methods that allow scientists to prove their existence by measuring light patterns from sun-like stars that dim slightly as the planets pass in front of them in orbit.

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La pizarra de Yuri » Blog Archive » Viviendo en un planeta joven de un universo bebé

La pizarra de Yuri » Blog Archive » Viviendo en un planeta joven de un universo bebé

www.lapizarradeyuri.com
Como te apunté al final del post anterior y en algún otro, la vida presente en la Tierra es sobrecogedoramente antigua. Tanto que no sabemos todavía cuándo surgió, pero no pudo ser mucho después del Bombardeo Intenso Tardío. Con certeza, tenemos fósiles de microorganismos complejos –posiblemente eucariontes– de hace 2.000 millones de años y microbios con 3.400 millones (como los de la foto a la derecha.) Con casi total certeza, hubo cianobacterias empezando a liberar oxígeno mediante fotosíntesis hace 3.500 millones de años. Hay grafito de origen probablemente biológico en Groenlandia Occidental, generado hace 3.700 millones de años. Por ahí, por ahí estimamos que anda LUCA, o sea el último antepasado común a todo lo que ahora mismo alienta sobre la faz de este planeta.
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