Four Candidates For Planet 9 Located

A concentrated three-day search for a mysterious, unseen planet in the far reaches of our own solar system has yielded four possible candidates. The search for the so-called Planet 9 was part of a real-time search with a Zooniverse citizen science project, in coordination with the BBC’s Stargazing Live broadcast from the Australian National University’s […]

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Planet 9 Can’t Run Forever. Two Asteroids Give Up Some Clues

Last year, Caltech astronomers Mike Brown and Konstantin Batygin found indirect evidence for the existence of a large planet in the outer reaches of our Solar System — likely located out past Pluto — and since then, the search has been on. The latest research continues to show signs of an unseen planet, the hypothetical […]

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Will You Be The Discoverer Of Planet 9?

Citizen science projects are a great way for anyone to be involved in the scientific process. Average, everyday folks have discovered things like supernovae, previously unseen craters on the Moon and Mars and even new planets orbiting a distant star. Now, you could be part of one of the most exciting quests yet: finding a […]

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JPL Predicts Mars’ Global Dust Storm To Arrive Within Weeks

These two images from the camera on NASA's Mars Global Surveyor show the effect that a global dust storm has on Mars. On the left is a normal view of Mars, on the right is Mars obscured by the haze from a dust storm. Image: NASA/JPL/MSSS

Our ability to forecast the weather here on Earth has saved countless lives from the onslaught of hurricanes and typhoons. We’ve gotten better at predicting space weather, too, and that has allowed us to protect sensitive satellites and terrestrial facilities from bursts of radiation and solar wind. Now, it looks as though we’re getting closer to predicting bad weather on Mars.

NASA’s Jet Propulsion Laboratory is forecasting the arrival of a global dust storm on Mars within weeks. The storm is expected to envelop the red planet, and reduce the amount of solar energy available to NASA’s rovers, Opportunity and Curiosity. The storm will also make it harder for orbiters to do their work.

Dust storms are really the only type of weather that Mars experiences. They’re very common. Usually, they’re only local phenomena, but sometimes they can grow to effect an entire region. In rarer cases, they can envelop the entire globe.

It’s these global storms that concern James Shirley, a planetary scientist at NASA’s Jet Propulsion Laboratory, in Pasadena, California. Shirley published a study showing that there is a pattern to these global storms. If his forecasted storm appears on time, it means that he has correctly determined that pattern.

“Mars will reach the midpoint of its current dust storm season on October 29th of this year. Based on the historical pattern we found, we believe it is very likely that a global dust storm will begin within a few weeks or months of this date,” Shirley said.

Predicting these huge dust storms will be of prime importance when humans gain a foothold on Mars. The dust could wreak havoc on sensitive systems, and can limit the effectiveness of solar power for weeks at a time.

But it’s not just future endeavours that are impacted by Martian dust storms. Spirit and Opportunity had to batten down the hatches when a global dust storm interrupted their exploration of Mars in 2007.

“We had to take special measures to enable their survival for several weeks with little sunlight to keep them powered.

John Callas is JPL’s project manager for Spirit and Opportunity. He describes the precautions that his team took during the 2007 dust storm: “We had to take special measures to enable their survival for several weeks with little sunlight to keep them powered. Each rover powered up only a few minutes each day, enough to warm them up, then shut down to the next day without even communicating with Earth. For many days during the worst of the storm, the rovers were completely on their own.”

We have observed 9 global dust storms on Mars since the first time in 1924, with the most recent one being the 2007 storm that threatened Spirit and Opportunity. Other storms were observed in 1977, 1982, 1994, and 2001. There’ve been many more of them, but we weren’t able to see them without orbiters and current telescope technology. And Earth hasn’t always been in a good position to view them.

Global dust storms have left their imprint on the early exploration of Mars. In 1971, NASA’s Mariner 9 orbiter reached Mars, and was greeted by a global dust storm that made it impossible to image the planet. Only two weeks later, the Soviet Mars 2 and Mars 3 missions arrived at Mars, and sent their landers to the surface.

Mars 2 crashed into the planet and was destroyed, but Mars 3 made it to the surface and landed softly. That made Mars 3 the first craft to land on Mars. However, it failed after only 14.5 seconds, likely because of the global dust storm. So not only was Mars 3 the first craft to land on Mars, it was also the first craft to be destroyed by a global dust storm.

If we had been able to forecast the global dust storm of 1971, Mars 3 may have been a successful mission. Who knows how that may have changed the history of Martian exploration?

James Shirley’s paper shows a pattern in global dust storms on Mars based on the orbit of Mars, and on the changing momentum of Mars as the gravity of other planets acts on it.

Mars takes about 1.8 years to orbit the Sun, but its momentum change caused by other planets’ gravity is in a 2.2 year cycle. The relationship between these two cycles is always changing.

What Shirley found is that global dust storms occur while Mars’ momentum is increasing during the first part of the dust storm season. When looking back at our historical record of Martian global dust storms, he found that none of them occurred in years when the momentum was decreasing during the first part of the dust storm season.

Shirley’s paper found that current conditions on Mars are also very similar to other times when global dust storms occurred. Since we are much more capable of watching Mars than at any time in the past, we should be able to quickly confirm if Shirley’s understanding of Martian weather is correct.

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Astronomers Discover Exoplanet With Triple Sunrises and Sunsets

This graphic shows the orbit of the planet in the HD 131399 system (red line) and the orbits of the stars (blue lines). The planet orbits the brightest star in the system, HD 131399A. Credit: ESO

In the famous scene from the Star Wars movie “A New Hope” we recall young Luke Skywalker contemplating his future in the light of a binary sunset on the planet Tatooine. Not so many years later in 2011, astronomers using the Kepler Space Telescope discovered Kepler-16b, the first Tatooine-like planet known to orbit two suns in a binary system. Now astronomers have found a planet in a triple star system where an observer would either experience constant daylight or enjoy triple sunrises and sunsets each day, depending on the seasons, which last longer than human lifetimes.

They used the SPHERE instrument on the European Southern Observatory’s Very Large Telescope to directly image the planet, the first ever found inside a triple-star system. The three stars are named HD 131399A, HD 131399B and HD 131399C in order of decreasing brightness; the planet orbits the brightest and goes by the chunky moniker HD 131399Ab.

Located about 320 light-years from Earth in the constellation of Centaurus the Centaur HD 131399Ab is about 16 million years old, making it also one of the youngest exoplanets discovered to date, and one for which we have a direct image. With a temperature of around 1,075° F (580° C) and the mass about four times that of Jupiter, it’s also one of the coldest and least massive directly-imaged exoplanets.

To pry it loose from the glare of its host suns, a team of astronomers led by the University of Arizona used a state of the art adaptive optics system to give razor-sharp images coupled with SPHERE, an instrument that blocks the light from the central star(s) similar to the way a coronagraph blocks the brilliant solar disk and allows study of the Sun’s corona. Finally, the region around the star is photographed in infrared polarized light to make any putative planets stand out more clearly against the remaining glare.

The planet, HD 131399Ab, is unlike any other known world — its orbit around the brightest of the three stars is by far the widest known within a multi-star system. It was once thought that planets orbiting a multi-star system would be unstable because of the changing gravitational tugs on the planet from the other two stars. Yet this planet remains in orbit instead of getting booted out of the system, leading astronomers to think that planets orbiting multiple stars might be more common that previously thought.

HD 131399Ab orbits HD 131399A, estimated to be 80% more massive than the Sun. Its double-star companions orbit about 300 times the Earth-Sun distance away. For much of the planet’s 550 year orbit, all three stars would appear close together in the sky and set one after the other in unique triple sunsets and sunrises each day. But when the planet reached the other side of its orbit around its host sun, that star and the pair would lie in opposite parts of the sky. As the pair set, the host would rise, bathing HD 131399Ab in near-constant daytime for about one-quarter of its orbit, or roughly 140 Earth-years.

https://www.youtube.com/watch?v=IB0vDQ6rHUU
Click to see a wonderful simulation showing how the planet orbits within the trinary system

Planets in multi-star systems are of special interest to astronomers and planetary scientists because they provide an example of how the mechanism of planetary formation functions in these more extreme scenarios. Since multi-star systems are just as common as single stars, so planets may be too.

How would our perspective of the cosmos change I wonder if Earth orbited triple suns instead of a single star? Would the sight deepen our desire for adventure like the fictional Skywalker? Or would we suffer the unlucky accident of being born at the start of a multi-decade long stretch of constant daylight? Wonderful musings for the next clear night under the stars.

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New Composite Image Of Saturn’s Polar Vortex Mesmerizes

This image of Saturn's southern polar vortex reveals previously unseen detail of the giant storm. Image: NASA/JPL/Space Science Institute

Atmospheric features on our Solar System’s gas giants dwarf anything similar on Earth. Earth’s atmosphere spawns hurricanes as larger as 1500 km in diameter. But on Saturn, a feature called the southern polar vortex has an eye that is 8,000 km across, or two thirds the diameter of the entire Earth.

A new high-resolution of Saturn’s southern polar vortex captured by the Cassini probe is ten times more detailed than any previous picture, and reveals details that were previously unseen. The image, which is a composite of two images taken by Cassini in July 2008, was captured when the spacecraft was 392,000 km from Saturn, and 56º below the plane of Saturn’s rings. Despite the distance and position, the image still has a resolution of 2 km per pixel.

Previous images of the vortex revealed clouds of immense proportions ringing the edge of the vortex, but showed the vortex itself to be clear. This is similar to a hurricane on Earth, where the eye itself is clear, but is ringed by wall-clouds of towering heights. This new image shows cloud formations within the vortex itself. The vortex is punctuated with wispy white cloud formations, and a smaller vortex at 10:00 within the larger formation.

The clouds inside the vortex are more than just pretty curiosities, of course. They are deep convective structures welling up from deep within Saturn’s atmosphere, and they form their own distinctive ring. This is all the more interesting because the eye of the vortex itself is generally clear, and is considered by scientists to be an area of downwelling.

The convection on display in Saturn’s southern polar vortex is an important clue to understanding how Saturn transfers energy through its atmosphere. On Earth, hurricanes are caused by warm water, and they move across the surface of the ocean as the warm water does.

Saturn, of course, has no liquid ocean, and the vortex is powered by warm atmospheric gases from deeper in Saturn. As they rise and cool they condense into clouds. The vortex also remains stationary, rather than following a warm mass of water. It’s locked into position over Saturn’s south pole.

Cassini’s narrow angle camera captured this new image, using a combination of two spectral filters. One was sensitive to wavelengths of polarized visible light centered at 617 nanometers, and the other to infrared light centered at 750 nanometers.

Cassini is a joint mission of NASA, the ESA, and the Italian Space Agency. It was launched in 1997, and has had its mission extended to September 2017. Cassini will end its mission in what the team operating Cassini is calling a Grand Finale. This will be a series of deep dives between Saturn and its rings, and will end with the spacecraft plunging into Saturn’s atmosphere.

To see a gallery of Cassini images, go here.

At Universe Today, we’ve written about Saturn’s polar vortices before. Have a look:

Violent Polar Cyclones on Saturn Imaged in Unprecedented Detail by Cassini

Hexagonal Structure at Saturn’s North Pole

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