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The dance of two suns

The life cycle of a Sun-like star

This image tracks the life of a Sun-like star, from its birth on the left side of the frame to its evolution into a red giant star on the right. On the left the star is seen as a protostar, embedded within a dusty disc of material as it forms. It later becomes a star like our Sun. After spending the majority of its life in this stage, the star’s core begins to gradually heat up, the star expands and becomes redder until it transforms into a red giant.

Following this stage, the star will push its outer layers into the surrounding space to form an object known as a planetary nebula, while the core of the star itself will cool into a small, dense remnant called a white dwarf star.

Marked on the lower timeline are where our Sun and solar twins 18 Sco and HIP 102152 are in this life cycle. The Sun is 4.6 billion years old and 18 Sco is 2.9 billion years old, while the oldest solar twin is some 8.2 billion years old —  the oldest solar twin ever identified. By studying HIP 102152, we can get a glimpse of what the future holds for our Sun.

Credit: ESO / M. Kornmesser

Travel Posters of Fantastic Excursions

What would the future look like if people were regularly visiting to other planets and moons? These travel posters give a glimpse into that imaginative future. Take a look and choose your destination:

The Grand Tour

Our Voyager mission took advantage of a once-every-175-year alignment of the outer planets for a grand tour of the solar system. The twin spacecraft revealed details about Jupiter, Saturn, Uranus and Neptune – using each planet’s gravity to send them on to the next destination.

Mars

Our Mars Exploration Program seeks to understand whether Mars was, is, or can be a habitable world. This poster imagines a future day when we have achieved our vision of human exploration of the Red Planet and takes a nostalgic look back at the great imagined milestones of Mars exploration that will someday be celebrated as “historic sites.”

Earth

There’s no place like home. Warm, wet and with an atmosphere that’s just right, Earth is the only place we know of with life – and lots of it. Our Earth science missions monitor our home planet and how it’s changing so it can continue to provide a safe haven as we reach deeper into the cosmos.

Venus

The rare science opportunity of planetary transits has long inspired bold voyages to exotic vantage points – journeys such as James Cook’s trek to the South Pacific to watch Venus and Mercury cross the face of the sun in 1769. Spacecraft now allow us the luxury to study these cosmic crossings at times of our choosing from unique locales across our solar system.

Ceres

Ceres is the closest dwarf planet to the sun. It is the largest object in the main asteroid belt between Mars and Jupiter, with an equatorial diameter of about 965 kilometers. After being studied with telescopes for more than two centuries, Ceres became the first dwarf planet to be explored by a spacecraft, when our Dawn probe arrived in orbit in March 2015. Dawn’s ongoing detailed observations are revealing intriguing insights into the nature of this mysterious world of ice and rock.

Jupiter

The Jovian cloudscape boasts the most spectacular light show in the solar system, with northern and southern lights to dazzle even the most jaded space traveler. Jupiter’s auroras are hundreds of times more powerful than Earth’s, and they form a glowing ring around each pole that’s bigger than our home planet. 

Enceladus

The discovery of Enceladus’ icy jets and their role in creating Saturn’s E-ring is one of the top findings of the Cassini mission to Saturn. Further Cassini discoveries revealed strong evidence of a global ocean and the first signs of potential hydrothermal activity beyond Earth – making this tiny Saturnian moon one of the leading locations in the search for possible life beyond Earth.

Titan

Frigid and alien, yet similar to our own planet billions of years ago, Saturn’s largest moon, Titan has a thick atmosphere, organic-rich chemistry and surface shaped by rivers and lakes of liquid ethane and methane. Our Cassini orbiter was designed to peer through Titan’s perpetual haze and unravel the mysteries of this planet-like moon.

Europa

Astonishing geology and the potential to host the conditions for simple life making Jupiter’s moon Europa a fascinating destination for future exploration. Beneath its icy surface, Europa is believed to conceal a global ocean of salty liquid water twice the volume of Earth’s oceans. Tugging and flexing from Jupiter’s gravity generates enough heat to keep the ocean from freezing.

You can download free poster size images of these thumbnails here: http://www.jpl.nasa.gov/visions-of-the-future/

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Celebrating 10 Years of Revolutionary Solar Views

Twin spacecraft give humanity unprecedented views of the entire sun at one time, traveling to the far side of our home star over the course of a 10-year mission.

These two spacecraft are called STEREO, short for Solar and Terrestrial Relations Observatory. Launched on Oct. 25, 2006, and originally slated for a two-year mission, both spacecraft sent back data for nearly eight years, and STEREO-A still sends information and images from its point of view on the far side of the sun.

STEREO watches the sun from two completely new perspectives. It also provides information invaluable for understanding the sun and its impact on Earth, other worlds, and space itself – collectively known as space weather. On Earth, space weather can trigger things like the aurora and, in extreme cases, put a strain on power systems or damage high-flying satellites.

Because the rest of our sun-watching satellites orbit near our home planet, STEREO’s twin perspectives far from Earth give us a unique opportunity to look at solar events from all sides and understand them in three dimensions.

We use data from STEREO and other missions to understand the space environment throughout the solar system. This helps operators for missions in deep space prepare for the sudden bursts of particles and magnetic field that could pose a danger to their spacecraft. 

STEREO has also helped us understand other objects in our solar system – like comets. Watching how a comet’s tail moves gives us clues about the constant stream of particles that flows out from the sun, called the solar wind.

STEREO is an essential piece of our heliophysics fleet, which includes 17 other missions. Together, these spacecraft shed new light on the sun and its interaction with space, Earth, and other worlds throughout the solar system. 

To celebrate, we’re hosting a Facebook Live event on Wednesday, Oct. 26. Join us at noon ET on the NASA Sun Science Facebook page to learn more about STEREO and ask questions. 

Learn more about how NASA studies the sun at: www.nasa.gov/stereo

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Scientist-astronaut Owen K. Garriott, Skylab 3 science pilot, is seen performing an extravehicular activity at the Apollo Telescope Mount (ATM) of the Skylab space station cluster in Earth orbit, photographed with a hand- held 70mm Hasselblad camera.  Garriott had just deployed the Skylab Particle Collection S149 Experiment.  The experiment is mounted on one of the ATM solar panels. The purpose of the S149 experiment was to collect material from interplanetary dust particles on prepared surfaces suitable for studying their impact phenomena.  Earlier during the EVA Garriott assisted astronaut Jack R. Lousma, Skylab 3 pilot, in deploying the twin pole solar shield.

First planet found around solar twin in star cluster

Astronomers have used ESO’s HARPS planet hunter in Chile, along with other telescopes around the world, to discover three planets orbiting stars in the cluster Messier 67. Although more than one thousand planets outside the Solar System are now confirmed, only a handful have been found in star clusters. Remarkably one of these new exoplanets is orbiting a star that is a rare solar twin — a star that is almost identical to the Sun in all respects.

Planets orbiting stars outside the Solar System are now known to be very common. These exoplanets have been found orbiting stars of widely varied ages and chemical compositions and are scattered across the sky. But, up to now, very few planets have been found inside star clusters. This is particularly odd as it is known that most stars are born in such clusters. Astronomers have wondered if there might be something different about planet formation in star clusters to explain this strange paucity.

The team used the HARPS planet-finding instrument on ESO’s 3.6-metre telescope at the La Silla Observatory. These results were supplemented with observations from several other observatories around the world. They carefully monitored 88 selected stars in Messier 67 over a period of six years to look for the tiny telltale motions of the stars towards and away from Earth that reveal the presence of orbiting planets.

This cluster lies about 2500 light-years away in the constellation of Cancer (The Crab) and contains about 500 stars. Many of the cluster stars are fainter than those normally targeted for exoplanet searches and trying to detect the weak signal from possible planets pushed HARPS to the limit.

Three planets were discovered, two orbiting stars similar to the Sun and one orbiting a more massive and evolved red giant star. The first two planets both have about one third the mass of Jupiter and orbit their host stars in seven and five days respectively. The third planet takes 122 days to orbit its host and is more massive than Jupiter.

The first of these planets proved to be orbiting a remarkable star — it is one of the most similar solar twins identified so far and is almost identical to the Sun. It is the first solar twin in a cluster that has been found to have a planet.

Two of the three planets are “hot Jupiters” — planets comparable to Jupiter in size, but much closer to their parent stars and hence much hotter. All three are closer to their host stars than the habitable zone where liquid water could exist.

Image credit: ESO/L. Calçada

Scientist-astronaut Owen K. Garriott, Skylab 3 science pilot, is seen performing an extravehicular activity at the Apollo Telescope Mount (ATM) of the Skylab space station cluster in Earth orbit, photographed with a hand- held 70mm Hasselblad camera. Garriott had just deployed the Skylab Particle Collection S149 Experiment. The experiment is mounted on one of the ATM solar panels. The purpose of the S149 experiment was to collect material from interplanetary dust particles on prepared surfaces suitable for studying their impact phenomena. Earlier during the EVA Garriott assisted astronaut Jack R. Lousma, Skylab 3 pilot, in deploying the twin pole solar shield.