Scientists reach back in time to discover some of the most power-packed galaxies | Clemson University News and Stories, South Carolina
http://newsstand.clemson.edu/...ach-back-in-time-to-discover-some-of-the-most-power-packed-galaxies/

When the universe was young, a supermassive black hole — bloated to the bursting point with stupendous power — heaved out a jet of particle-infused energy
that raced through the vastness of space at nearly the speed of light. Billions of years later, a trio of Clemson University scientists, led by College of Science
astrophysicist Marco Ajello, has identified this black hole and four others similar to it that range in age from 1.4 billion to 1.9 billion years old. These objects
emit copious gamma rays, light of the highest energy, that are billions of times more energetic than light that is visible to the human eye.

The previously known earliest gamma-ray blazars — a type of galaxy whose intense emission is powered by extremely powerful relativistic jets launched by monstrous
black holes — were more than 2 billion years old. Currently, the universe is estimated to be approximately 14 billion years old.

First evidence of rocky planet formation in Tatooine system
http://www.ucl.ac.uk/...cles/0217/270217-First-evidence-of-rocky-planet-formation-in-Tatooine-system

Published today in Nature Astronomy and funded by the Science and Technology Facilities Council and the European Research Council,
the study reports on the remains of shattered asteroids orbiting a double sun consisting of a white dwarf and a brown dwarf roughly
1000 light-years away in a system called SDSS 1557.

The discovery is remarkable because the debris appears to be rocky and suggests that terrestrial planets like Tatooine – Luke Skywalker’s
home world in Star Wars – might exist in the system. To date, all exoplanets discovered in orbit around double stars are gas giants,
similar to Jupiter, and are thought to form in the icy regions of their systems.

In contrast to the carbon-rich icy material found in other double star systems, the planetary material identified in the SDSS 1557 system
has a high metal content, including silicon and magnesium. These elements were identified as the debris flowed from its orbit onto the surface
of the star, polluting it temporarily with at least 1017 g (or 1.1 trillion US tons) of matter, equating it to an asteroid at least 4 km in size.

A Challenge to Our View of How Stars Die
http://aasnova.org/2017/02/27/a-challenge-to-our-view-of-how-stars-die/

For the first time ever, we’ve been able to watch the complete metamorphosis of an unusual explosion from one type of
supernova to another. What do our observations of SN 2014C mean for our understanding of how massive stars end their lives?

Categorizing Explosions

Supernovae — the explosions that mark the end of massive stellar lifetimes — are broadly categorized into two types: Type I
supernovae, which do not show evidence of hydrogen in their spectra, and Type II supernovae, which do.

The majority of supernovae in both categories have the same cause: the fuel in the star’s core is exhausted, and the core
subsequently collapses under its own gravity. But a supernova will appear as a Type I or Type II depending upon whether
or not the star had already lost its outer hydrogen envelope long before the explosion.

Study suggests we reclassify the moon as a planet – reopening a centuries-old debate
https://theconversation.com/...eclassify-the-moon-as-a-planet-reopening-a-centuries-old-debate-73575

Every now and then a scientific paper makes a real splash. We had one recently, to judge from recent headlines. “Moon rises to claim
its place as a planet” said The Sunday Times on February 19, while the Mail Online asked “Is this lunarcy?”. The articles were among
many responding to the humble paper: “A Geophysical Planet Definition”, which suggested that the criteria for determining what constitutes
a planet need an overhaul. It argued that the moon, Pluto and several other bodies in the solar system should be upgraded to planets.

The paper, published in Planetary and Lunar Science, was written by a team including Alan Stern. Stern is famous for NASA’s New Horizons mission,
which made its spectacular flyby of Pluto in July 2015. The paper is a bit technical, but it basically argues that the geophysics of a body
should determine whether it is a planet – not just whether it orbits the sun.

Stars regularly ripped apart by black holes in colliding galaxies - News releases - News - The University of Sheffield
http://www.sheffield.ac.uk/news/nr/stars-ripped-apart-black-holes-1.684679

Astronomers based at the University of Sheffield have found evidence that stars are
ripped apart by supermassive black holes 100 times more often than previously thought.

Until now, such stellar cannibalism – known as Tidal Distruption Events, or TDEs – had
only been found in surveys which observed many thousands of galaxies, leading astronomers
to believe they were exceptionally rare: only one event every 10 000 to 100 000 years
per galaxy.

Martian Winds Carve Mountains, Move Dust, Raise Dust
https://www.nasa.gov/feature/jpl/martian-winds-carve-mountains-move-dust-raise-dust

On Mars, wind rules. Wind has been shaping the Red Planet's landscapes for billions of years and continues to do so today. Studies using
both a NASA orbiter and a rover reveal its effects on scales grand to tiny on the strangely structured landscapes within Gale Crater.

NASA's Curiosity Mars rover, on the lower slope of Mount Sharp -- a layered mountain inside the crater -- has begun a second campaign of
investigating active sand dunes on the mountain's northwestern flank. The rover also has been observing whirlwinds carrying dust and
checking how far the wind moves grains of sand in a single day's time.




This pair of images shows effects of one Martian day of wind blowing sand underneath NASA's Curiosity Mars rover on a non-driving day for the rover.
Each image was taken just after sundown by the rover's downward-looking Mars Descent Imager (MARDI). The area of ground shown in the images spans
about 3 feet (about 1 meter) left-to-right.

The first image was taken on Jan. 23, 2017, during the 1,587th Martian day, or sol, of Curiosity's work on Mars. Figure A is this image with a scale
bar in centimeters. The second was taken on Jan. 24, 2017 (Sol 1588). The day-apart images by MARDI were taken as a part of investigation of wind's
effects during Martian summer, the windiest time of year in Gale Crater.

Volcanic hydrogen spurs chances of finding exoplanet life | Cornell Chronicle
http://news.cornell.edu/stories/2017/02/volcanic-hydrogen-spurs-chances-finding-exoplanet-life

Hunting for habitable exoplanets now may be easier: Cornell astronomers report that hydrogen pouring from
volcanic sources on planets throughout the universe could improve the chances of locating life in the cosmos.

Planets located great distances from stars freeze over. “On frozen planets, any potential life would be buried under layers of ice, which would make it
really hard to spot with telescopes,” said lead author Ramses Ramirez, research associate at Cornell’s Carl Sagan Institute. “But if the surface is warm
enough – thanks to volcanic hydrogen and atmospheric warming – you could have life on the surface, generating a slew of detectable signatures.”

Combining the greenhouse warming effect from hydrogen, water and carbon dioxide on planets sprinkled throughout the cosmos, distant stars could expand
their habitable zones by 30 to 60 percent, according to this new research. “Where we thought you would only find icy wastelands, planets can be nice and
warm – as long as volcanoes are in view,” said Lisa Kaltenegger, Cornell professor of astronomy and director of the Carl Sagan Institute.

The Curiosity of Martian Mud Cracks
https://www.youtube.com/watch?v=eYIHTVeGQcg

Planets With Elliptical Orbits May Be More Habitable Than We Thought | Inverse
https://www.inverse.com/...le/28191-planets-elliptical-orbits-colder-habitable-extraterrestrial-life

Turns out there might actually be more planets out there that could potentially support
extraterrestrial life, precisely because these planets aren’t as hot as scientists thought.

Why are there different “flavors” of iron around the Solar System? | Carnegie Institution for Science
https://carnegiescience.edu/node/2146

New work from Carnegie’s Stephen Elardo and Anat Shahar shows that interactions between iron and nickel under the extreme pressures
and temperatures similar to a planetary interior can help scientists understand the period in our Solar System’s youth when planets
were forming and their cores were created. Their findings are published by Nature Geoscience.

Earth and other rocky planets formed as the matter surrounding our young Sun slowly accreted. At some point in Earth’s earliest years,
its core formed through a process called differentiation—when the denser materials, like iron, sunk inward toward the center. This
formed the layered composition the planet has today, with an iron core and a silicate upper mantle and crust.

Scientists can’t take samples of the planets’ cores. But they can study iron chemistry to help understand the differences between
Earth’s differentiation event and how the process likely worked on other planets and asteroids.

Most Planets Are Colder Than Thought | News | Astrobiology
https://astrobiology.nasa.gov/news/most-planets-are-colder-than-thought/
There Might be More Planets in the Habitable Zone

A common assumption in the search for habitable abodes beyond Earth is that the average temperature of planets always increases the more elliptical their orbit is.
Now, scientists from the Planetary Habitability Laboratory (PHL) and the Arecibo Observatory in Puerto Rico have shown that planets in elliptical orbits are generally
colder than previously believed.

Planets can move around their parent star in orbits that are not perfectly circular. These elliptical orbits put planets sometimes significantly closer or farther
from their star, thus contributing to extreme temperature changes. This is not the case of Earth, and probably for the exoplanets orbiting the stars Proxima Centauri
or TRAPPIST-1, but true for many known planets around other stars.

From rocks in Colorado, evidence of a 'chaotic solar system' - Astrobiology Magazine
http://www.astrobio.net/also-in-news/rocks-colorado-evidence-chaotic-solar-system/

Plumbing a 90 million-year-old layer cake of sedimentary rock in Colorado, a team of scientists from the University of Wisconsin-Madison and
Northwestern University has found evidence confirming a critical theory of how the planets in our solar system behave in their orbits around the sun.

The finding, published Feb. 23, 2017 in the journal Nature, is important because it provides the first hard proof for what scientists call the “chaotic
solar system,” a theory proposed in 1989 to account for small variations in the present conditions of the solar system. The variations, playing out over
many millions of years, produce big changes in our planet’s climate — changes that can be reflected in the rocks that record Earth’s history.

PHL včera updatovali přehled PO exoplanet (o TRAPPIST-1)
The Habitable Exoplanets Catalog - Planetary Habitability Laboratory @ UPR Arecibo
http://phl.upr.edu/projects/habitable-exoplanets-catalog

http://www.eso.org/public/usa/videos/eso1706j/

https://www.youtube.com/watch?v=WOzPdGS7vRs

A přidám dvě čerstvá videa od Cool Worlds. Davida Kippinga sleduji teprve tak půl roku, ale jak on
tak parta nadšených studentů exoplanet kolem něj by mohla vyvážet entuziasmus z poznání napříč sluneční soustavou.. :)

https://www.youtube.com/watch?v=UMbWUyEwirs

https://www.youtube.com/watch?v=16mROb2O2rA

VIRGO:
VIRGO: Sheltonova nesmrtelná pracovní historka krásně zpracovaná jako animák.
Poprvé jsem ji se zatajeným dechem hltal v devadesátkách v podání pana Grygara,
tohle mi přišlo po třech dekádách neméně poetické... :)

A star explodes: The story of supernova 1987A | Science News
https://www.youtube.com/watch?v=67LLoVnwUgw

Cassini: Mission to Saturn: Hardy Objects in Saturn's F Ring
https://saturn.jpl.nasa.gov/resources/7606/

As NASA's Cassini spacecraft continues its weekly ring-grazing orbits, diving just past the outside of Saturn's F ring, it is tracking several small, persistent objects there.