This artist's concept depicts a planetary system so compact that it's more like Jupiter and its moons than a star and its planets. Astronomers using data from NASA's Kepler mission and ground-based telescopes recently confirmed that the system, called KOI-961, hosts the three smallest exoplanets currently known to orbit a star other than our Sun. An exoplanet is a planet that resides outside of our Solar System.
The star, which is located about 130 light-years away in the Cygnus constellation, is a red dwarf that is one-sixth the size of the Sun, or just 70 percent bigger than Jupiter. The star is also cooler than our Sun, and gives off more red light than yellow.
The smallest of the three planets, called KOI-961.03, is actually located the farthest from the star, and is pictured in the foreground. This planet is about the size of Mars, with a radius of 0.57 times that of Earth. The next planet to the upper right is KOI-961.01, which is 0.78 times the radius of Earth. The planet closest to the star is KOI-961.02, with a radius 0.73 times the Earth's.
All three planets whip around the star in less than two days, with the closest planet taking less than half a day. Their close proximity to the star also means they are scorching hot, with temperatures ranging from 350 to 836 degrees Fahrenheit (176 to 447 degrees Celsius). The star's habitable zone, or the region where liquid water could exist, is located far beyond the planets.
The ground-based observations contributing to these discoveries were made with the Palomar Observatory, near San Diego, California, and the W.M. Keck Observatory atop Mauna Kea in Hawaii.
Magnetic loops carry gas and dust above disks of planet-forming material circling stars, as shown in this artist's conception. These loops give off extra heat, which NASA's Spitzer Space Telescope detects as infrared light. The colors in this illustration show what an alien observer with eyes sensitive to both visible light and infrared wavelengths might see.
The Matterhorn is a mountain of the Alps, straddling the main watershed and border between Switzerland and Italy. It is a huge and near-symmetrical pyramidal peak in the extended Monte Rosa area of the Pennine Alps, whose summit is 4,478 metres (14,692 ft) high, making it one of the highest summits in the Alps and Europe. The four steep faces, rising above the surrounding glaciers, face the four compass points and are split by the Hörnli, Furggen, Leone and Zmutt ridges. The mountain overlooks the Swiss town of Zermatt in the canton of Valais to the north-east and the Italian town of Breuil-Cervinia in the Aosta Valley to the south. Just east of the Matterhorn is Theodul Pass, the main passage between the two valleys on its north and south sides and a trade route since the Roman Era.
The Alps, Europe
May 26, 2014
Image Credit & Copyright: Stephen Burt
Explanation from: https://en.wikipedia.org/wiki/Matterhorn
This artist's conception shows planetary system called Epsilon Eridani. Observations from NASA's Spitzer Space Telescope show that the system hosts two asteroid belts, in addition to previously identified candidate planets and an outer comet ring.
Epsilon Eridani is located about 10 light-years away in the constellation Eridanus. It is visible in the night skies with the naked eye.
The system's inner asteroid belt appears as the yellowish ring around the star, while the outer asteroid belt is in the foreground. The outermost comet ring is too far out to be seen in this view, but comets originating from it are shown in the upper right corner.
Astronomers think that each of Epsilon Eridani's asteroid belts could have a planet orbiting just outside it, shepherding its rocky debris into a ring in the same way that Jupiter helps keep our asteroid belt confined. The planet near the inner belt was previously identified in 2000 via the radial velocity, or "star wobble," technique, while the planet near the outer belt was inferred when Spitzer discovered the belt.
The inner belt orbits at a distance of about 3 astronomical units from its star -- or about the same position as the asteroid belt in our own Solar System (an astronomical unit is the distance between Earth and our Sun). The second asteroid belt lies at about 20 astronomical units from the star, or a position comparable to Uranus in our Solar System. The outer comet ring orbits from 35 to 90 astronomical units from the star; our solar system's analogous Kuiper Belt extends from about 30 to 50 astronomical units from the Sun.
This artist's concept depicts Kepler-186f, the first validated Earth-size planet to orbit a distant star in the habitable zone -- a range of distance from a star where liquid water might pool on the planet's surface. The discovery of Kepler-186f confirms that Earth-size planets exist in the habitable zones of other stars and signals a significant step closer to finding a world similar to Earth.
The size of Kepler-186f is known to be less than ten percent larger than Earth, but its mass, composition and density are not known. Previous research suggests that a planet the size of Kepler-186f is likely to be rocky. Prior to this discovery, the "record holder" for the most "Earth-like" planet went to Kepler-62f, which is 40 percent larger than the size of Earth and orbits in its star's habitable zone.
Kepler-186f orbits its star once every 130 days and receives one-third the energy that Earth does from the Sun, placing it near the outer edge of the habitable zone. If you could stand on the surface of Kepler-186f, the brightness of its star at high noon would appear as bright as our Sun is about an hour before sunset on Earth.
Kepler-186f resides in the Kepler-186 system about 500 light-years from Earth in the constellation Cygnus. The system is also home to four inner planets, seen lined up in orbit around a host star that is half the size and mass of the Sun.
The artistic concept of Kepler-186f is the result of scientists and artists collaborating to imagine the appearance of these distant worlds.
It’s Antarctic winter on Pluto. The Sun has not been visible for twenty years in this frigid south polar region; it will not shine again for another 80 years. The only source of natural light is starlight and moonlight from Pluto’s largest moon, Charon.
If you stood on the night region of Pluto at that moment – looking up at a distinctly gray Charon - it would appear seven times larger in the sky than Earth’s moon. Charon, although three billion miles from the Sun, is so close to Pluto and so ice-covered that it would be only five times dimmer than the full moon seen from Earth. At your feet, the icy surface – resembling a sooty snow bank - would be bathed in Charon’s faint glow. The area around you would be dim, but not so dark that you would bump into things.
On your moonlight stroll on Pluto you’d notice that your shadow, cast by Charon, is much less defined than your shadow from moonlight on Earth. A wisp of cloud might even pass in front of Charon as you look up.
If you stood on Pluto’s Charon-facing side – you would see Charon go through a cycle of phases during a “Pluto Day” - 6 days and 10 hours—but not the complete set of phases our moon displays to us on Earth. Seen from Pluto during that time, Charon would go from a wide crescent, to a “quarter moon,” then to gibbous (partway between quarter and full phases), and back again.
This artist's concept illustrates what the night sky might look like from a hypothetical alien planet in a star system with an asteroid belt 25 times as massive as the one in our own Solar System.
NASA's Spitzer Space Telescope found evidence for such a belt around the nearby star called HD 69830, when its infrared eyes spotted dust, presumably from asteroids banging together. The telescope did not find any evidence for a planet in the system, but astronomers speculate one or more may be present.
The movie begins at dusk on the imaginary world, when HD 69830, like our Sun, has begun to set over the horizon. Time is sped up to show the onset of night and the appearance of a brilliant band of light. This light comes from dust in a massive asteroid belt, which scatters sunlight.
In our Solar System, anybody observing the skies on a moonless night far from city lights can see the sunlight that is scattered by dust in our asteroid belt. Called zodiacal light and sometimes the "false dawn," this light appears as a dim band stretching up from the horizon when the Sun is about to rise or set. The light is faint enough that the disk of our Milky Way galaxy remains the most prominent feature in the sky.
In contrast, the zodiacal light in the HD 69830 system would be 1,000 times brighter than our own, outshining even the Milky Way.
The dramatic moment that our star, the Sun, appears to be cloaked in darkness by the Moon during the Total Solar Eclipse of 9th March 2016 in Indonesia. The Sun peers out from behind the Moon and resembles the shape of a diamond ring, caused by the rugged edge of the Moon allowing some beads of sunlight to shine through in certain places.
This is an artist's concept of a close binary pair of stars that are merging to form a blue-straggler-class star. Blue stragglers are so named because they seem to be lagging behind in their rate of aging compared with the population from which they formed. The merger stirs up hydrogen fuel and causes the resulting more massive star to undergo nuclear fusion at a faster rate, causing it to burn hotter and bluer. Probing the star-filled, ancient hub of our Milky Way, the Hubble Space Telescope has found blue stragglers for the first time within our galaxy's bulge.
Image Credit: NASA, ESA and G. Bacon (STScI)
Explanation from: https://www.spacetelescope.org/images/opo1116c/
A southward-looking panorama combining images from both cameras of the Mast Camera (Mastcam) instrument on NASA's Curiosity Mars Rover shows diverse geological textures on Mount Sharp.
Three years after landing on Mars, the mission is investigating this layered mountain for evidence about changes in Martian environmental conditions, from an ancient time when conditions were favorable for microbial life to the much-drier present.
Gravel and sand ripples fill the foreground, typical of terrains that Curiosity traversed to reach Mount Sharp from its landing site. Outcrops in the midfield are of two types: dust-covered, smooth bedrock that forms the base of the mountain, and sandstone ridges that shed boulders as they erode. Rounded buttes in the distance contain sulfate minerals, perhaps indicating a change in the availability of water when they formed. Some of the layering patterns on higher levels of Mount Sharp in the background are tilted at different angles than others, evidence of complicated relationships still to be deciphered.
The scene spans from southeastward at left to southwestward at right. The component images were taken on April 10 and 11, 2015, the 952nd and 953rd Martian days (or sols) since the rover's landing on Mars on Aug. 6, 2012, UTC (Aug. 5, PDT). Images in the central part of the panorama are from Mastcam's right-eye camera, which is equipped with a 100-millimeter-focal-length telephoto lens. Images used in outer portions, including the most distant portions of the mountain in the scene, were taken with Mastcam's left-eye camera, using a wider-angle, 34-millimeter lens.