Storms seen on Uranus!

The seventh planet from the Sun is a boring one.  The best photos we have of Uranus were obtained in January 1986 during the passing of Voyager 2, and they revealed a cold, pale-green, ball of Methane four times the diameter of Earth with very little visible activity.

Boring Old Uranus Credit: NASA/JPL/Voyager

Since then, we’ve learned a lot about Uranus, and it’s far more interesting than we thought.  It has rings, a magnetosphere, and numerous moons.  It has a 98 degree axial tilt, meaning that the poles of the planet cycle through 42 years of sunlight and 42 years of darkness during it’s 84 year journey around the Sun.

Winds on Uranus can reach 900 Km/h, which is exactly what led to a series of new storms observed by Astronomers using the Keck telescope in Hawaii.

Storms on Uranus in Infrared. Image credit: Imke de Pater, University of California, Berkeley / Keck Observatory images.

The above image, taken in infrared on August 6th, 2014, shows large storms in the atmosphere of Uranus.  The images were taken with the 10-meter Keck telescope using adaptive optics, where parts of the telescope’s main mirror quickly shift to correct for the distortion caused by atmospheric turbulence.  This technique has given some of the clearest images of distant objects even taken with ground-based telescopes, rivalling the quality of space telescopes such as Hubble.

“This type of activity would have been expected in 2007, when Uranus’s once-every-42-year equinox occurred and the Sun shined directly on the equator,” Said Heidi Hammel of the Association of Universities for Research in Astronomy.  “But we predicted that such activity would have died down by now. Why we see these incredible storms now is beyond anybody’s guess.”

Uranus is made mostly of Methane and Ammonia in solid ice form, with an atmosphere of Hydrogen, Helium and a bit of Methane to give it the dull green colour.  Since it has no internal heat source, all observed weather should be driven by energy from the Sun.  The stormy results were unexpected, even though the team has been following the weather patterns on Uranus for 10 years.

The storms on Uranus are similar to those observed on the other gas giants, possibly due to differential rotation of the gases in the atmosphere, the Coriolis force.

When we closely observe a distant world, as with a microscope observing smaller structures, we can find a surprising degree of complexity.  Uranus is a simple gas planet, but beneath the think obscuring Methane clouds, we see a world of vortices and storms, magnetism and frigidity, surrounded by complex rings and moons.

The Philae Landing: In 3D and Audio!

It’s been a week since the historic landing of Philae on the comet 67P/Churyumov-Gerasimenko, and the data keeps coming in.  As an Astronomy communicator, I’m always looking for great visual aids in my Astronomy in Action Shows.  They are more valuable to me than any piece of written news because they illustrate a concept quickly and efficiently.  A picture truly is worth a thousand words.

But audio and video can be worth even more!

Recently an image of the Philae landing was released, showing two images approximately 2 minutes apart.  This image gives a 3-Dimensional perspective of the comet as the lander approached it.  Break out your blue/red shades.

Credit: ESA/Rosetta/Philae/ROLIS/DLR

These images were taken with the ROLIS camera when Philae was less than 3 Km from the comet.  The resolution is about 10 feet per pixel, and we can see the landing site below centre of the image.

The image is great, but there is also some audio of THE LANDER HITTING THE COMET!!!!

Can you tell I’m excited? This is incredible, listen for yourself.

It’s a short thud, but very characteristic of what we found on the comet: a thin layer of powdery dust covering a hard shell of ice and rock.

“The Philae lander came into contact with a soft layer several centimeters thick,” said Klaus Seidensticker, lead scientist for the CASSE instrument from the German Aerospace Center’s Institute of Planetary Research, Berlin. “Then, just milliseconds later, the feet encountered a hard, perhaps icy layer on 67P/Churyumov-Gerasimenko.”

This sound originated further away than anything you have or may ever hear in your life.  Incredible!

 

Magnetic Fields on Distant Exoplanets?

Twenty Years of exoplanet research has seen incredible advances in detecting planets orbiting distant stars, as well as their size, orbit period, orbit distance, and even atmospheric composition.  But the next step in understanding exoplanets is to learn about their magnetic fields.

We know that many exoplanets should have magnetic fields.  It makes sense, since nearly every world in our own solar system has some sort of magnetism.  But for the first time, an international team of Astronomers, led by Kristina Kislyakova of the Space Research Institute of the Austrian Academy of Sciences, have discovered a way to detect magnetic fields on an exoplanet.

They looked at H-Alpha images of the planet HD 209458b as it passed in front of its star.  Looking at the planet’s absorption of stellar radiation, they were able to model the size and shape of the surrounding gas cloud, which allowed them to model the planet’s magnetosphere.  When only one such model would reproduce the observed distribution of hydrogen in the atmosphere, the team realized they were successful.

Credit: NASA/ESA/CNRS/Alfred Vidal-Madjar

The planet HD 209458b is about 150 light years from Earth in the constellation Pegasus.  It is known as a ‘hot-Jupiter,’ meaning it is a planet comparable to the size and mass of Jupiter, with an orbit distance even closer than Mercury.  Hot Jupiters were the first exoplanets to be detected due to their size and strong gravitational effect on their home star.  This particular planet is the first to have it’s atmospheric composition determined, and its relative ease of study is why astronomers use it as a baseline to test new methods in exoplanet research.

To increase the accuracy of their model, the Astronomers accounted for some of the parameters that alter the interactions between the planet’s atmosphere and the stellar wind, such as gravitational effects, pressure, radiation acceleration, and spectral line broadening.

According to Kislyakova, “The planet’s magnetosphere was relatively small beeing only 2.9 planetary radii corresponding to a magnetic moment of only 10% of the magnetic moment of Jupiter.”

Astronomers study magnetic fields due to their influence on the evolution of a planet.  They shield the planet from Solar Wind particles and can protect against the erosion of the planet’s atmosphere.

On Earth, the magnetic field protects life on Earth from harmful Solar radiation, producing the gorgeous Aurorae near the poles.  On Mars, where there is no magnetic field, solar wind particles batter the planet, blasting away any atmosphere Mars may have had in the past.

Uncanny Alignment Across Billions of Light Years

Quasars are Galaxies with incredibly massive Black Holes at their centre.  These Black Holes are fuelled by a swirling disc of material that can be ejected in a long jet along their axis of rotation, all due to the conservation of angular momentum.  This accretion disc can be so hot that it causes the central region of the Galaxy to shine more brightly than the entire Galaxy of stars surrounding it.

A Belgian team using the Very Large Telescope (VLT) studied a population of 93 Quasars spread over Billions of Light-Years, and noticed that the rotation axes of the Quasars were aligned with each other, even though they were so immensely far apart.  They probed further, and discovered that the rotation axes also aligned with the large-scale structure of the Universe.

Credit: ESO/M. Kornmesser

When we look at the large scale of the Universe over Billions of Light-Years, we see that Galaxies are not evenly distributed.  They are clumped together in a cosmic web of filaments with vast empty regions in between.  The team performing the study found that the rotation axes of the quasars lined up with the direction of the filaments where they were located.

Now you might be saying “Well there are Billions of Galaxies in the Universe, shouldn’t this happen by sheer chance?”

That’s exactly what the Astronomers said, but they have estimated that the probability of this kind of alignment is less than 1%.

These alignments could mean that Astronomers are missing a key concept in models of the early Universe.  Perhaps we are close, but just need a few tweaks to accurately model the Cosmos.

 

Here’s what the Surface of the (2nd) Largest Asteroid Looks like

Vesta is the 2nd-largest Asteroid in the well known asteroid belt between the orbits of Mars and Jupiter.  525 Km in diameter, it is very big for an asteroid.  If it was much bigger we would call it a dwarf planet.

The Dawn Spacecraft, launched in 2007, stopped by Vesta in 2011 and stuck with it until 2012 as it orbited the sun.  We are still seeing the results of that rendezvous, and just recently NASA released a complete map of the surface features of Vesta.

Credit: NASA/JPL-Caltech/ASU

It’s amazing to see so many interesting surface features on such a small world.  Geologic processes from the early Solar System are seen suspended in time across millions of comets and asteroids that have remained untouched in 4.6 Billion years.

Another great map of Vesta gives us 3D perspective, also helping to explain why Vesta is not a planet.  The lack of spherical shape prevents it from being promoted to a dwarf planet, but as you can see, it’s close.

If Vesta was a bit larger, it’s own gravity would pull it into a sphere.  The largest Asteroid in the belt, Ceres, is almost twice as large as Vesta, and is spherical, giving it dwarf planet status.  This is actually the next target for Dawn, and it is currently in transit, expected to arrive next year.

Why send spacecraft to asteroids? The same reason we landed the Philae spacecraft on the comet last week. We want to study the early Solar System so that we can learn about the building blocks that gave rise to the Earth and eventually, the life that saturates it.

Every mission is a small piece of the great puzzle of the Universe, and as we piece them together we gain an understanding of our own distant history, painting a picture of our existence.