PLUTO! Explored at Last! What a World!
The New Horizons mission flew by Pluto in July of this year, after a 9.5 year flight. Pluto was just a tiny speck in our telescopes before this mission, and now we know it is a world with probable recent geologic activity, ice mountains that reach 11,000 feet tall, and canyons that scrape across its surface. Visit the mission website to see the images below and many more, and read all about the incredible world.
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| My favorite picture of Pluto. Click here to see it full size - you must! Look at the detail of those mountains! And that plain! And that tenuous atmosphere! |
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| Pluto went from being a tiny speck in our telescopes, to being a fantastic, surprising, detailed world. |
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| Pluto's varied terrain is a delight. Towering mountains, craters, and smooth plains. |
I have gotten so much joy out of this mission. Never before have I seen a world explored bit by bit. Unless we get a mission out to the other dwarf planets in the Kuiper Belt, or an orbiter that can discover more about Uranus and Neptune's moons, we may never have the experience again!
You can read all of my posts and see many more images from the New Horizons mission at the following links:
Exoplanets!
This has been a great year for news about planets orbiting other stars in our galaxy. Since 2009, the Kepler Space Telescope has been searching small portions of the Milky Way for the small dip in light that results when a planet passes in front of (transits) a star. So far, this incredibly successful mission has confirmed (meaning detected 2 times or more) 1030 exoplanets, and identified about 5,000 exoplanet candidates! Scientists are particularly interested in finding worlds that are somewhat Earth-like, since Earth is the only planet we know of that can support life. This year, NASA announced the discovery of Kepler 452b, a potentially rocky planet that could be similar to Earth. This planet is within the habitable zone of it's star - the zone where liquid water could exist. It is about 60% larger than Earth, and takes about the same amount of time to complete an orbit around its star as Earth around the Sun. Its star is just a little older than our Sun, and in the same temperature range. It is one of the most Earth-like planets discovered so far!
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| Artist depiction comparing Earth with Kepler 452b. Image Credit: NASA/AMES/JPL |
Water on Mars!
Ever since our telescopes could resolve features on Mars, scientists have been wondering if water flows or flowed on the surface in the past. Percival Lowell was convinced that he saw canals on Mars, indicating an advanced civilization of Martians.
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| Lowell's drawings of Martian canals. Image Credit: Wikipedia Commons |
Lowell's canals were imaginary, and he very possibly advanced the idea to sell books, yet the idea of water flowing on Mars was not outrageous. Scientists found no evidence of constructed water features on Mars, but there are many land forms that suggest old rivers, and shores of dried up lakes. Liquid water certainly was once abundant on Mars; in fact, a third of the planet may have been covered in a liquid ocean millions of years in the past. This is exciting, because Earth is the only place in our Solar System with stable liquid water on its surface, and the only place yet discovered that supports life. Scientists believe that if they can find another place with liquid water, they are closer to finding life elsewhere in the Universe. That is why many people were very excited for NASA's announcement that liquid water currently flows on the surface of Mars.
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| Seasonal changes showing salty liquid water flowing on the steep slopes of Mars. Image Credit |
The announcement in September wasn't exactly a surprise to many scientists, because the evidence used to confirm the presence of water has been around for several years, but science is a gradual process, and the evidence had piled up enough that NASA felt confident in announcing that highly salty water positively existed in a liquid form on Mars today, and even flowed on steep slopes. The "water" is so salty that is referred to as hydrated salts. It might be less misleading to say that slightly damp, very salty, dirt flows as the seasons change on Mars. This is still exciting, because it adds evidence to the idea that Mars once hosted a hospitable environment for life.
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| An imagination of Mars as a watery world, based on geological data. Image Credit |
The Exploration of World Ceres
This March, the Dawn mission entered orbit around the dwarf planet Ceres, which orbits the Sun within the asteroid belt.
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| Global view of Ceres from Dawn. Image Credit |
The Dawn spacecraft is powered by solar power and ion propulsion, and is the first mission to ever orbit two bodies in the Solar System. You can read all about the fascinating and advanced engineering that made Dawn possible in this previous post: Dawn in Orbit around Ceres!
The most surprising thing about Ceres are these exceptionally bright spots.
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| No, they are not lights from an alien civilization, Internet. Image Credit |
Theories flew across the internet as these spots came into focus on Ceres. They are much more reflective than the surrounding surface, and don't look like a young impact crater. After many observations and much deliberation, mission scientists announced that the bright spots are likely caused by a concentration of salts, specifically magnesium sulfate hexahydrite, and also ammonia rich clay.
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| Ceres and bright spots in false color. Blue is associated with bright areas on Ceres, and seems to be consistent with the presence of salts. Image Credit |
You can read more about the Dawn mission and see images of Vesta in this post: Little Spacecrafts, Big Missions
Global Ocean on Enceladus
Similar to the Mars story, scientists have long known that there was water under Enceladus' icy crust. Saturn's tiny moon has geysers that have been observed spewing icy crystals into space, feeding Saturn's E-ring, by the Cassini spacecraft. However, it took many years of observation, and much accumulation of evidence to be able to say that there is a global liquid ocean under Enceladus' icy crust.
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| Enceladus' icy plumes, imaged by Cassini. Image Credit |
Researchers spent years analyzing the very slight wobble of the moon as it orbits Saturn. They determined that the wobble could only be accounted for if its outer ice shell is not frozen solid to its interior, meaning a global ocean must be present.
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| Enceladus in color. Image Credit |
Cassini has detected organic molecules in the ice plumes from Enceladus. This moon is one of the worlds in the Solar System that is most likely to be able to support life, other than Earth!
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| Image Credit |
Read more about the Cassini mission in this post: Congratulations, Cassini!
Rosetta Won't Stop Being Awesome
In 2014, the European Space Agency (ESA) did something incredible - their Rosetta mission fell into orbit around a comet. And if that wasn't impressive enough, they then LANDED A ROBOT on it.
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| Rosetta and comet 67P. Image Credit |
This
is a very ambitious mission. Comet 67P is tiny, less than 3 miles in
diameter, so it doesn't have very much gravity to help Rosetta fall into
orbit. The engineers had to very carefully plan Rosetta's trajectory so
that it would slow down and fall into place right next to the comet.
The spacecraft flew 12 years before it reached its destination!
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| Comet 67P as it approached the Sun and became more active. Image Credit |
In November of 2014, ESA landed a little robot, Philae, on the comet. Unfortunately, the lander bounced three times, and didn't land in a spot where its solar panels could be charged. It was able to complete 80% of its science objectives, but has been mostly unresponsive in 2015. Read more about Philae and the landing here: HUMANS landed a ROBOT on a COMET!!!
The orbiter is working great and just keeps sending back awesome images of this comet!
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| Image Credit |
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| A close up view of the comet. Image Credit |
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| Image Credit |
You can see an abundance of gorgeous images from the Rosetta mission at its Flickr page.
You can read more about the Rosetta mission here: Go, Go, Rosetta and Philae!
And one last personal favorite....
I got to explore some of the world's most advanced telescopes this year, at the top of the Andes mountains in Chile. It was an incredible experience I will never forget.
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| The vivid night sky at CTIO in Chile, with the Blanco Telescope. Image Credit: Renae Kerrigan |
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| Feeling on top of the world. Image Credit: Tim Spuck |
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| CTIO bathed in starlight. Image Credit: Renae Kerrigan |
Visiting Observatories at the Top of the World
My Chilean Adventure Begins
Solstices
Astronomy Everywhere in Santiago
Telescopes, Stars, and the Joy of Exploration
Cerro Tololo to La Serena to San Pedro
ALMA OSF "Low" Site
Among the ALMA Radio Antennas
Off to the Green Bank Radio Telescope
Here's to an excellent year of science in 2015. Keep advocating for science and astronomy, and the future will be bright indeed. There is so much more to explore.
You can always learn about space and science at the Dome Planetarium at the Peoria Riverfront Museum. Follow us on Facebook and Twitter for daily updates!
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