Stars die and reborn…They get so hot that the nuclei of the atoms fuse together deep within them to make the oxygen we breathe, the carbon in our muscles, the calcium in our bones, the iron in our blood. All was cooked in the fiery hearts of long vanished stars…The cosmos is also within us. We’re made of star stuff. We are a way for the cosmos to know itself.
— 

Carl Sagan

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Planet Found in Habitable Zone Around Nearest Star

So this is kind of a big deal. Astronomers have just discovered a new planet orbiting the closest star to our Sun, Proxima Centauri. The planet is called Proxima b and orbits the star every 11.2 days. It has a mass that is estimated to be 1.3 times the Earth’s. Unlike the Earth, though, it’s only 7.3 million kilometers from the star—much closer than Earth to the Sun—but Proxima is so faint and cool it receives about two-thirds the amount of light and heat the Earth does. Essentially that means that it’s in Proxima’s habitable zone which opens the possibility of liquid water on its surface.

Researchers estimate that if the planet has an atmosphere (which isn’t confirmed), it may be between 86 to 104 degrees Fahrenheit on the surface. Without an atmosphere, it could be -22 to -40 degrees Fahrenheit. To put that in perspective, Earth would be -4 degrees if it didn’t have an atmosphere.

Before we go all Interstellar and have Matthew McConaughey check it out, though, it is 40 trillion km away, which means even the fastest ship would still take tens of thousands of years to get there! 

LEARN MORE (via Slate)

Scientists just discovered the closest Earth-like planet ever

It seems the rumors about a new exoplanet in our backyard are true. Scientists have discovered a small, rocky exoplanet orbiting around our closest star, Proxima Centauri. The planet, named Proxima b, is about 1.3 times the size of Earth. Scientists think it’s warm enough to sustain an important resource.
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Astronomers Have Discovered a Planet Orbiting the Closest Star to our Solar System!

From ESO (The European Southern Observatory):

Astronomers using ESO telescopes and other facilities have found clear evidence of a planet orbiting the closest star to the Sun, Proxima Centauri (a red dwarf star, too faint to be seen with the unaided eye, 4.2 light-years from the Solar System). The long-sought world, designated Proxima b, orbits its cool red parent star every 11 days and has a temperature suitable for liquid water to exist on its surface. This rocky world is a little more massive than the Earth and is the closest exoplanet to us — and it may also be the closest possible abode for life outside the Solar System.
The paper describing this milestone finding is published in the journal Nature.

During the first half of 2016 Proxima Centauri was regularly observed with the HARPS spectrograph on the ESO 3.6-metre telescope at La Silla in Chile and simultaneously monitored by other telescopes around the world [1]. This was the Pale Red Dot campaign, in which a team of astronomers led by Guillem Anglada-Escudé, from Queen Mary University of London, was looking for the tiny back and forth wobble of the star that would be caused by the gravitational pull of a possible orbiting planet [2]

Phil Plait explains further in his article (read all here):

Because it’s the closest star to the Sun, astronomers have looked at it for decades to see if there’s any evidence of a planet. There have been false alarms over the years, all eventually shown to be errors.

But this time it looks like it’s very much real. The difference is the quality of data, because our technology and techniques have improved mightily recently. Using two different cameras on two different telescopes, the astronomers divided the light from Proxima into a spectrum. They looked for subtle and periodic changes in the spectrum that would be due to a planet orbiting the star. As the planet moved, it would tug on the star;Proxima would make a little circle as the planet made a bigger one. This creates a Doppler shift in the spectrum, which in principle can be measured.

The faster the planet orbits, the bigger the shift, and usually the easier it is to detect. The motion Proxima b imparts on its star is very small, just one or two meters per second.* That’s very hard to detect.

But the eyesight of the cameras was sharp, and the ability of the astronomers to tease out the signal greater. 

He also gives a down-to-earth perspective: 

Mind you, we know nothing of its composition, or even its size. It may be completely uninhabitable, or it might be Eden. There’s no way to know. So be cautious here: It’s likely to be Earth-size, but we don’t know if it’s Earth-like.

Either way, it’s more than 40 trillion kilometers away, so we’re not going there any time soon. The fastest spacecraft we’ve ever launched would take many tens of thousands of years to get there. Don’t pack your underthings just yet.

Still, this is terribly, terribly exciting. We’ve only known for sure about the existence of exoplanets—worlds orbiting alien suns—since 1992. The first found were orbiting a dead star, a pulsar. The first planet orbiting a Sun-like star wasn’t found until 1995, and in the next two decades we built telescopes dedicated to looking for them, and as of today we know of over 3,000 such strange, new worlds.

Quite a few are Earth-size, and fewer possibly Earth-like. Still, we can make estimates that there are billions of Earth-size planets in the galaxy.

And now we know that it’s possible that the nearest one is, on a cosmic scale, right next door.

*Correction: it was originally misstated that this was the speed the planet goes around the star, not the speed of the star itself.

Psychedelic Saturn 

Saturn’s rings were bright and its northern hemisphere defined by bright features as NASA’s Voyager 2 approached Saturn, which it encountered on Aug. 25, 1981. Three images, taken through ultraviolet, violet and green filters on July 12, 1981, were combined to make this photograph. Voyager 2 was 43 million kilometers (27 million miles) from Saturn when it took this photograph. 

Credit: NASA/JPL

Scientists find monster young star that’s 30 times the mass of our sun

Scientists just discovered a star more than 30 times the mass of the sun, and it’s probably not done growing yet. The star is still just a “protostar,” or a baby star that doesn’t have a fusion-powered core yet, so this is a rare opportunity for scientists to study how giant stars like this one form. They also spotted a “Keplerian” disc around the star.

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The relative sizes of a number of objects, including the three (known) members of Alpha Centauri triple system and some other stars for which the angular sizes have also been measured with the Very Large Telescope Interferometer (VLTI) at the ESO Paranal Observatory. The Sun and planet Jupiter are also shown for comparison.
Credit:
ESO

The Swirling Core of the Crab Nebula : At the core of the Crab Nebula lies a city-sized, magnetized neutron star spinning 30 times a second. Known as the Crab Pulsar, it’s actually the rightmost of two bright stars, just below a central swirl in this stunning Hubble snapshot of the nebula’s core. Some three light-years across, the spectacular picture frames the glowing gas, cavities and swirling filaments bathed in an eerie blue light. The blue glow is visible radiation given off by electrons spiraling in a strong magnetic field at nearly the speed of light. Like a cosmic dynamo the pulsar powers the emission from the nebula, driving a shock wave through surrounding material and accelerating the spiraling electrons. With more mass than the Sun and the density of an atomic nucleus, the spinning pulsar is the collapsed core of a massive star that exploded. The Crab Nebula is the expanding remnant of the star’s outer layers. The supernova explosion was witnessed on planet Earth in the year 1054. via NASA

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Today ten years ago an IAU resolution stated an official definition for the term “planet” who ultimately excluded Pluto as a planet of our Solar System, and reclassified it as “dwarf planet”.

Image via NASA: What Is Pluto?
Caption: The New Horizons spacecraft helped us see Pluto and its largest moon Charon more clearly than we could see them with telescopes.

A Euler diagram showing the relationship between objects in the Solar System (excluding stars) - Wikimedia Commons

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Planet Found in Habitable Zone Around Nearest Star

Pale Red Dot campaign reveals Earth-mass world in orbit around Proxima Centauri

Astronomers using ESO telescopes and other facilities have found clear evidence of a planet orbiting the closest star to Earth, Proxima Centauri. The long-sought world, designated Proxima b, orbits its cool red parent star every 11 days and has a temperature suitable for liquid water to exist on its surface. This rocky world is a little more massive than the Earth and is the closest exoplanet to us — and it may also be the closest possible abode for life outside the Solar System.

Just over four light-years from the Solar System lies a red dwarf star that has been named Proxima Centauri as it is the closest star to Earth apart from the Sun. This cool star in the constellation of Centaurus is too faint to be seen with the unaided eye and lies near to the much brighter pair of stars known as Alpha Centauri AB.

At times Proxima Centauri is approaching Earth at about 5 kilometres per hour — normal human walking pace — and at times receding at the same speed. This regular pattern of changing radial velocities repeats with a period of 11.2 days. Careful analysis of the resulting tiny showed that they indicated the presence of a planet with a mass at least 1.3 times that of the Earth, orbiting about 7 million kilometres from Proxima Centauri — only 5% of the Earth-Sun distance.

At times Proxima Centauri is approaching Earth at about 5 kilometres per hour — normal human walking pace — and at times receding at the same speed. This regular pattern of changing radial velocities repeats with a period of 11.2 days. Careful analysis of the resulting tiny Doppler shifts showed that they indicated the presence of a planet with a mass at least 1.3 times that of the Earth, orbiting about 7 million kilometres from Proxima Centauri — only 5% of the Earth-Sun distance.

Although Proxima b orbits much closer to its star than Mercury does to the Sun in the Solar System, the star itself is far fainter than the Sun. As a result Proxima b lies well within the habitable zone around the star and has an estimated surface temperature that would allow the presence of liquid water. Despite the temperate orbit of Proxima b, the conditions on the surface may be strongly affected by the ultraviolet and X-ray flares from the star — far more intense than the Earth experiences from the Sun.

This discovery will be the beginning of extensive further observations, both with current instruments and with the next generation of giant telescopes such as the European Extremely Large Telescope (E-ELT). Proxima b will be a prime target for the hunt for evidence of life elsewhere in the Universe. Indeed, the Alpha Centauri system is also the target of humankind’s first attempt to travel to another star system, the StarShot project. 

More info: European Southern Observatory

Breaking News: August 24,

The closest potentially habitable planet to our solar system has been found!

In a discovery that has been years in the making, researchers have confirmed the existence of a rocky planet named Proxima b orbiting Proxima Centauri, the closest star to our sun, according to a new study. It is the closest exoplanet to us in the universe.

Given the fact that Proxima b is within the habitable zone of its star, means liquid water should exist on the surface, it may also be the closest possible home for life outside of our solar system,. Because of its location, the researchers hope it provides an opportunity for possible “robotic exploration in the near future. 

This artist’s impression above shows a view of the surface of the planet Proxima b. It is not only nice for having it in our neighborhood, but it’s a dream come true for astronomers if we think about follow-up observation.“Proxima Centauri coexists with a binary star in Alpha Centauri, a well-studied star system that serves as a neighbor to our sun. Proxima b is a mere 4.2 light-years away from our solar system.

Johannes Kepler - Geometrical Harmonies in the Perfect Solids, “Harmonices Mundi”, 1619.

Kepler was convinced “that the geometrical things have provided the Creator with the model for decorating the whole world”. In Harmony, he attempted to explain the proportions of the natural world - particularly the astronomical and astrological aspects - in terms of music. The central set of “harmonies” was the Musica Universalis or “Music of the Spheres”.

Kepler began by exploring regular polygons and regular solids, including the figures that would come to be known as Kepler’s solids.
Harmony resulted from the tones made by the souls of heavenly bodies - and in the case of astrology, the interaction between those tones and human souls. In the final portion of the work, Kepler dealt with planetary motions, especially relationships between orbital velocity and orbital distance from the Sun. Similar relationships had been used by other astronomers, but Kepler treated them much more precisely and attached new physical significance to them.