When you want to see the stars, find someplace dark
Early science results from NASA’s Juno mission to Jupiter portray the largest planet in our solar system as a complex, gigantic, turbulent world, with Earth-sized polar cyclones, plunging storm systems that travel deep into the heart of the gas giant, and a mammoth, lumpy magnetic field that may indicate it was generated closer to the planet’s surface than previously thought.
Juno launched on Aug. 5, 2011, entering Jupiter’s orbit on July 4, 2016. The findings from the first data-collection pass, which flew within about 2,600 miles (4,200 kilometers) of Jupiter’s swirling cloud tops on Aug. 27, are being published this week in two papers in the journal Science, as well as 44 papers in Geophysical Research Letters.
Continue reading “A Whole New Jupiter: First Science Results from NASA’s Juno Mission”
Dawn has been in orbit around Ceres for over a year now, having entered orbit back on March 6th, 2015. Most of the dwarf planet has been photographed and mapped in high resolution now, creating beautiful imagery that reveals a great deal of interesting terrian. As we have seen with other dwarf planets like Pluto, these little worlds are surprisingly dynamic places, hardly the dead rocks one might have expected.
The bright features in Occator crater have been revealed to be some sort of cryovolcano. While not certain, the bright is likely to be water ice, or perhaps a briny, salt and water mixture. There has even been some evidence of vapor observed over the crater, possibly from sublimating ices.
I am sure this is a large disappointment to those who claimed it was some sort of alien base. Not that this has stopped the claims, they are just more modest in size. You can find YouTube videos of folks combing through the high resolution images and claiming any little feature that is slightly regular looking is some alien artifact.
More enjoyable to watch is a JPL video pointing out the highlights of Ceres…
NASA’s Dawn spacecraft has returned new images captured on approach to its historic orbit insertion at the dwarf planet Ceres. Dawn will be the first mission to successfully visit a dwarf planet when it enters orbit around Ceres on Friday, March 6.
Recent images show numerous craters and unusual bright spots that scientists believe tell how Ceres, the first object discovered in our solar system’s asteroid belt, formed and whether its surface is changing. As the spacecraft spirals into closer and closer orbits around the dwarf planet, researchers will be looking for signs that these strange features are changing, which would suggest current geological activity.
“Studying Ceres allows us to do historical research in space, opening a window into the earliest chapter in the history of our solar system,” said Jim Green, director of NASA’s Planetary Science Division at the agency’s Headquarters in Washington. “Data returned from Dawn could contribute significant breakthroughs in our understanding of how the solar system formed.”
Dawn began its final approach phase toward Ceres in December. The spacecraft has taken several optical navigation images and made two rotation characterizations, allowing Ceres to be observed through its full nine-hour rotation. Since Jan. 25, Dawn has been delivering the highest-resolution images of Ceres ever captured, and they will continue to improve in quality as the spacecraft approaches.
More than three-quarters of the planet candidates discovered by NASA’s Kepler spacecraft have sizes ranging from that of Earth to that of Neptune, which is nearly four times as big as Earth. Such planets dominate the galactic census but are not represented in our own solar system. Astronomers don’t know how they form or if they are made of rock, water or gas.
Included in the findings are five new rocky planets ranging in size from 10 to 80 percent larger than Earth. Two of the new rocky worlds, dubbed Kepler-99b and Kepler-406b, are both 40 percent larger in size than Earth and have a density similar to lead. The planets orbit their host stars in less than five and three days respectively, making these worlds too hot for life as we know it.
A major component of these follow-up observations was Doppler measurements of the planets’ host stars. The team measured the reflex wobble of the host star, caused by the gravitational tug on the star exerted by the orbiting planet. That measured wobble reveals the mass of the planet: the higher the mass of the planet, the greater the gravitational tug on the star and hence the greater the wobble.
Continue reading “Kepler and Keck Provide Insights on Enigmatic Planets”
In the fable of the town and country mice, the country mouse visits his city-dwelling cousin to discover a world of opulence. In the early cosmos, billions of years ago, galaxies resided in the equivalent of urban or country environments. Those that dwelled in crowded areas called clusters also experienced a kind of opulence, with lots of cold gas, or fuel, for making stars.
Today, however, these galactic metropolises are ghost towns, populated by galaxies that can no longer form stars. How did they get this way and when did the fall of galactic cities occur?
A new study from NASA’s Spitzer Space Telescope finds evidence that these urban galaxies, or those that grew up in clusters, dramatically ceased their star-making ways about 9 billion years ago (our universe is 13.8 billion years old). These galactic metropolises either consumed or lost their fuel. Galaxies in the countryside, by contrast, are still actively forming stars.
“We know the cluster galaxies we see around us today are basically dead, but how did they get that way?” wondered Mark Brodwin of the University of Missouri-Kansas City, lead author of this paper, published in the Astrophysical Journal. “In this study, we addressed this question by observing the last major growth spurt of galaxy clusters, which happened billions of years ago.”
A spectacular image of Saturn from above. Even better, the image was assembled by an amateur astronomer, Gordan Ugarkovic, working with Cassini imagery taken on October 10th. Click on the image to zoom in, then zoom in some more! You can see exquisite data in the polar cloud-tops and in the rings. Keep an eye out for the shepherd moons at the edges of the various rings…
Gone are the days of being able to count the number of known planets on your fingers. Today, there are more than 800 confirmed exoplanets — planets that orbit stars beyond our sun — and more than 2,700 other candidates. What are these exotic planets made of? Unfortunately, you cannot stack them in a jar like marbles and take a closer look. Instead, researchers are coming up with advanced techniques for probing the planets’ makeup.
One breakthrough to come in recent years is direct imaging of exoplanets. Ground-based telescopes have begun taking infrared pictures of the planets posing near their stars in family portraits. But to astronomers, a picture is worth even more than a thousand words if its light can be broken apart into a rainbow of different wavelengths.
Those wishes are coming true as researchers are beginning to install infrared cameras on ground-based telescopes equipped with spectrographs. Spectrographs are instruments that spread an object’s light apart, revealing signatures of molecules. Project 1640, partly funded by NASA’s Jet Propulsion Laboratory, Pasadena, Calif., recently accomplished this goal using the Palomar Observatory near San Diego.
Continue reading “Sifting Through the Atmospheres of Far-off Worlds”
