Posted on by Fraser Cain

What Happens When The Poles Flip?

What Happens When The Poles Flip?

Have you heard the terrifying news that the Earth’s poles are going to flip? What does “flipping” mean? And if the Earth’s poles do flip, are we in any danger?

Have you heard the startling news that the Earth’s poles might flip? Perhaps in the response to a close pass from the mysterious Planet X? Are you imagining the entire Earth actually flipping over on its side or rotating upside down, possibly while Yakkity Sax plays in the background? When will this happen? Can this happen?

First, there’s no secret planet hurtling through the Solar System causing chaos and orbital disturbances. So could the Earth spontaneously physically flip over? Some planets have already been tilted and flipped.

Take a look at Uranus. Its orbital tilt is 98-degrees. We assume the planet started with the same tilt as the rest of the Solar System, and some event in the ancient past caused it to fall over. It could have collided with another planet, billions of years ago, or gravitational interactions with other giant planets pushed it over.

And then there’s Venus, its axial tilt is 177-degrees. That’s essentially upside down. Venus is turning in the opposite direction from every other planet in the Solar System. Standing on the surface of Venus, you would see the Sun rise in the West and set in the East. Astronomers don’t know why this happened, perhaps it was gravitational interactions or a collision with another planet.

To actually flip a planet off its axis would take an event so catastrophic that it would devastate the planet. Don’t worry, as far as we know, those kinds of events and interactions stopped happening billions of years ago.
That’s the good news. The Earth isn’t likely to just fall over, or get bashed on its side like an office tower under the might of Godzilla

Schematic illustration of Earth's magnetic field. Credit/Copyright: Peter Reid
Schematic illustration of Earth’s magnetic field. Credit/Copyright: Peter Reid

Now what about those magnetic poles. On Earth, they can and do reverse on a regular basis. The Earth is often shown like a giant bar magnet, with a north magnetic pole and a south magnetic pole. Over vast periods of time, the Earth’s north pole becomes its south pole, and vice versa. Geologists measure the magnetic configuration of iron particles in ancient lava flows. in one part of the lava flow, the particles oriented with one magnetic configuration, and then in another, the particles were reversed. It turns out the planet reverses its polarity every 450,000 years, and the last reversal happened about 780,000 years ago. Which means it could happen in the next few thousand years.

If the Earth’s poles did reverse, what would happen to us? If the magnetic field disappeared entirely, the planet would be bathed in radiation from the Sun, which would likely cause an increase in cancer. But the Earth’s atmosphere would still protect us from majority of radiation.

What about mass extinctions? Scientists have wondered if there’s a link between them and magnetic reversals.
Fortunately for us, there doesn’t seem to be any connection. Whenever geomagnetic reversals happened in the past, it didn’t devastate life on Earth. So don’t worry about it.

There is a pretty good chance it won’t happen in our lifetime, and maybe not for hundreds of thousands of years. And even if the Earth’s poles flip, it wouldn’t be the end of the world. You might need to take a sharpie to your compass though.

Posted on by Nancy Atkinson

Astrophoto: Uranus at Opposition

Uranus, imaged from Italy on October 3, 2013, when the planet was at opposition. Credit and copyright: Giuseppe Petricca.

Last week, we asked if you were looking for an observing challenge: looking for planet Uranus when it reached opposition — where it is opposite the Sun the sky, meaning the planet rises as the Sun sets. Giuseppe Petricca from Italy took the challenge and ran with it. His skies over Sulmona, Abruzzo in Italy cleared, and not even 12 hours after the official time of opposition he got this shot using his new Toucam Pro II on a Newtonian 200/1000 on EQ5 unmotorized mount.

Nice!

Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.

Posted on by Elizabeth Howell

Saturn Storm’s ‘Suck Zone’ Shown In Spectacular Cassini Shots

A false-color image, taken by the Cassini spacecraft, of a huge hurricane at Saturn's north pole. Credit: NASA/JPL-Caltech/SSI

Checking out the above pictures of a Saturn hurricane, one can’t help but wonder: how close was the Cassini spacecraft to spiralling down into gassy nothingness?

These dizzying images of a hurricane on Saturn, of course, came as the spacecraft zoomed overhead at a safe distance. NASA’s goal in examining this huge hurricane is to figure out its mechanisms and to compare it to what happens on our home planet.

Hurricanes on Earth munch on water vapor to keep spinning. On Saturn, there’s no vast pool of water to draw from, but there’s still enough water vapor in the clouds to help scientists understand more about how hurricanes on Earth begin, and continue.

“We did a double take when we saw this vortex because it looks so much like a hurricane on Earth,” stated Andrew Ingersoll, a Cassini imaging team member at the California Institute of Technology in Pasadena. “But there it is at Saturn, on a much larger scale, and it is somehow getting by on the small amounts of water vapor in Saturn’s hydrogen atmosphere.”

A false-color view of Saturn's storm, as seen through Cassini's wide-angle camera. The blue bands at the edge are Saturn's rings. Credit: NASA/JPL-Caltech/SSI
A false-color view of Saturn’s storm, as seen through Cassini’s wide-angle camera. You can see the eye in dark red, the jet stream in yellowish-green, and low-lying clouds in orange. The blue bands at the edge are Saturn’s rings. Credit: NASA/JPL-Caltech/SSI

There’s one big change in hurricane activity you’d observe if suddenly shifted from Earth to Saturn: this behemoth — 1,250 miles (2,000 kilometers) wide, about 20 times its Earthly counterparts — spins a heckuva lot faster.

In the eye, winds in the wall speed more than four times faster than what you’d find on Earth. The hurricane also sticks around at the north pole. On Earth, hurricanes head north (and eventually dissipate) due to wind forces generated by the planet’s rotation.

“The polar hurricane has nowhere else to go, and that’s likely why it’s stuck at the pole,” stated Kunio Sayanagi, a Cassini imaging team associate at Hampton University in Hampton, Va.

Cassini initially spotted the storm in 2004 through its heat-seeking infrared camera, when the north pole was shrouded in darkness during winter.

The spacecraft first caught the storm in visible light in 2009, when NASA controllers altered Cassini’s orbit so that it could view the poles.

Saturn, of course, is not the only gas giant in the solar system with massive hurricanes. Jupiter’s Great Red Spot has been raging since before humans first spotted it in the 1600s. It appears to be shrinking, and could become circular by 2040.

Neptune also has hurricanes that can reach speeds of 1,300 miles (2,100 kilometers) an hour despite its cold nature; it even had a Great Dark Spot spotted during Voyager’s flypast in 1989 that later faded from view. Uranus, which scientists previously believed was quiet, is a pretty stormy place as well.

Check out this YouTube video for more details on how Saturn’s storm works.

Source: Jet Propulsion Laboratory

Posted on by Jason Major

27 Years Ago: Voyager 2’s Visit to Uranus

Image of Uranus’ crescent taken by a departing Voyager 2 on January 25, 1986 (NASA/JPL)

27 years ago today, January 24, 1986, NASA’s Voyager 2 spacecraft sped past Uranus, becoming simultaneously the first and last spacecraft to visit the blue-tinged gas giant, third largest planet in the Solar System.

The image above shows the crescent-lit Uranus as seen by Voyager 2 from a distance of about 965,000 km (600,000 miles.) At the time the spacecraft had already passed Uranus and was looking back at the planet on its way outwards toward Neptune.

Although composed primarily of hydrogen and helium, trace amounts of methane in Uranus’ uppermost atmosphere absorb most of the red wavelengths of light, making the planet appear a pale blue color.

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Image of the 1,500-km-wide Oberon acquired by Voyager 2 on Jan. 24, 1986 (NASA/JPL)

The second of NASA’s twin space explorers (although it launched first) Voyager 2 came within 81,800 kilometers (50,600 miles) of Uranus on January 24, 1986, gathering images of the sideways planet, its rings and several of its moons. Voyager 2 also discovered the presence of a magnetic field around Uranus, as well as 10 new small moons.

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Three moons discovered by Voyager 2 in 1986 (NASA/JPL)

Data gathered by Voyager 2 revealed that Uranus’ rate of rotation is 17 hours, 14 minutes.

At the time of this writing, Voyager 2 is 15,184,370,900 km from Earth and steadily moving toward the edge of the Solar System at a speed of about 3.3 AU per year. At that distance, signals from Voyager take just over 14 hours and 4 minutes to reach us.

See images from Voyager 2’s visit of Uranus here, and check out a video of the August 20, 1977 launch below along with more images from the historic Voyager mission’s “Grand Tour” of the outer Solar System.

Posted on by Nancy Atkinson

Uranus has Bizarre Weather

New infrared images of Uranus show details not seen before. Credit: NASA/ESA/L. A. Sromovsky/P. M. Fry/H. B. Hammel/I. de Pater/K. A. Rages

Here’s the scene: a thick, tempestuous atmosphere with winds blowing at a clip of 900 km/h (560 mph); massive storms that would engulf continents here on Earth, and temperatures in the -220 C (-360 degree F) range. Sounds like a cold Hell, but this is the picture emerging of the planet Uranus, revealed in new high-resolution infrared images from the Keck Observatory in Hawaii, exposing in incredible detail the bizarre weather of a planet that was once thought to be rather placid.

“My first reaction to these images was ‘wow’ and then my second reaction was ‘WOW,'” said Heidi Hammel, a co-investigator on the new observations. “These images reveal an astonishing amount of complexity in Uranus’ atmosphere. We knew the planet was active, but until now much of the activity was masked by noise in our data.”

Voyager 2’s view of Uranus. Credit: NASA

With its beautiful blue atmosphere, Uranus can seem rather tranquil at first glance. Even the flyby of Voyager 2 in 1986 revealed a rather “bland” blue ball. But coming into focus now with the new are large weather systems, and even though they are probably much less violent than storms on Earth, the weather on Uranus is just…bizarre.

“Some of these weather systems,” said Larry Sromovsky, from the University of Wisconsin-Madison who led the new study using the Keck II telescope, “stay at fixed latitudes and undergo large variations in activity. Others are seen to drift toward the planet’s equator while undergoing great changes in size and shape. Better measures of the wind fields that surround these massive weather systems are the key to unraveling their mysteries.”

Sromovsky, Hammel and their colleagues are using new infrared techniques to deliver some of the “most richly detailed views of Uranus yet obtained by any instrument on any observatory. No other telescope could come close to producing this result,” Sromovsky said.

What they are seeing are previously undetected, small but widely distributed weather feature, and they hope the movements of these features can help make sense of the planet’s odd pattern of winds.

They observed a scalloped band of clouds just south of Uranus’ equator and a swarm of small convective features in the north polar regions of the planet. Features like this don’t seem to be in the southern polar regions, but are similar to the types of “popcorn” –type clouds seen on Saturn. Uranus’ north pole is not visible from Earth night now, but when it does come into view, the researchers wouldn’t be surprised to see a polar vortex feature similar to what has been seen at Saturn’s south pole.

The driver of these features must be solar energy because there is no other detectable internal energy source.

“But the Sun is 900 times weaker there than on Earth because it is 30 times further from the Sun, so you don’t have the same intensity of solar energy driving the system,” said Sromovsky. “Thus the atmosphere of Uranus must operate as a very efficient machine with very little dissipation. Yet the weather variations we see seem to defy that requirement.”

One possible explanation, is that methane is pushed north by an atmospheric conveyor belt toward the pole where it wells up to form the convective features visible in the new images. The phenomena may be seasonal, the team said, but they are still working on trying to put together a clear seasonal trend in the winds of Uranus.

“Uranus is changing,” he said, “and there is certainly something different going on in the two polar regions.”

The images were released at the American Astronomical Society’s Division for Planetary Sciences meeting taking place this week.

Source: University of Wisconsin-Madison

Posted on by Nancy Atkinson

The Moon from Earth As You’ve Never Seen it Before

The Morteus region on the Moon, taken from the suburbs of Paris, France. Credit: Thierry Legault. Used by permission.

Think this is an orbital view of the Moon? Guess again. Astrophotographer Thierry Legault took this image from his backyard in the suburbs of Paris, France! He’s taken a series of images of the Moon the past few nights that will blow your mind when you consider they were taken from Earth, within the confines of the metropolis of Paris (largest city in France, 5th largest in the EU, 20th largest in the world). Thierry used a Celestron C14 EdgeHD (356mm) and Skynyx2.2 camera. You definitely want to click on these images for the larger versions on Thierry’s website, and he suggests using a full-HD screen in subdued surroundings.

Additionally, Thierry also recently took images of Mercury and Uranus that include incredible detail.

Plato, Mons Pico and Montes Teneriffe as seen on Sept 8th, 2010, from the suburbs of Paris, France. Credit: Thierry Legault. Used by permission.

The clarity and detail are just tremendous. See all of Thierry’s recent lunar images at this link. He has a collection of twelve different images of various regions on the Moon and all are stunning.

Below are his images of Mercury and Uranus. In the image of Mercury, surface details are visible, and the cloud belts are even visible on the images of Uranus:

Incredibly detailed view of Mercury on August 23, 2012, as seen from Blancourt, France. Credit: Thierry Legault. Used by permission.

Uranus, as seen on September 9, 2012 from Blancourt, France. Credit: Thierry Legault. Used by permission.

Thanks, as always, to Thierry Legault for sharing his images and allowing us to post them. Check out his website: http://legault.perso.sfr.fr/ for more wonderful images and information about how he does his amazing astrophotography.

Posted on by Jason Major

Hubble Reveals Curious Auroras on Uranus

Bright spots of Uranus' short-lived auroras have been imaged with the Hubble Space Telescope.

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Astronomers have finally succeeded in capturing the first Earth-based images of the curious and fleeting auroras of Uranus using the Hubble Space Telescope, careful planning… and no small amount of luck.

Unlike Earthly auroras, whose long-lived curtains of glowing green, red and purple have been the subject of countless stunning photos over the past months, Uranus’ auroras are relatively dim and short-lived, lasting only several minutes at most. They were first witnessed on Uranus by Voyager 2 in 1986, but never by any Earth-based telescopes until November of 2011. Using Hubble, an international team of astronomers led by Laurent Lamy from the Observatoire de Paris in Meudon, France spotted two instances of auroras on the distant planet… once on November 16 and again on the 29th.

Two instances of Uranian aurora imaged in Nov. 2011. (L. Lamy)

Auroras are known to be created by a planet’s magnetosphere, which on Earth is aligned closely with the rotational axis — which is why auroras are seen nearest the polar latitudes. But Uranus’ magnetic field is quite offset from its rotational axis, which in turn is tipped nearly 98 degrees relative to its orbital path. In other words, Uranus travels around the Sun rolling on its side! And with a 60-degree difference between its magnetic and rotational axis, nothing on Uranus seems to point quite where it should. This — along with its 2.5-billion-mile (4 billion km) distance — makes for a “very poorly known” magnetic field.

“This planet was only investigated in detail once, during the Voyager flyby, dating from 1986. Since then, we’ve had no opportunities to get new observations of this very unusual magnetosphere,” said Laurent Lamy, lead author of the team’s paper Earth-based detection of Uranus’ aurorae.

Rather than rings of bright emissions, as witnessed on Earth as well as Saturn and Jupiter, the Uranian auroras appeared as bright spots of activity on the planet’s daytime side — most likely a result of Uranus’ peculiar orientation, as well as its seasonal alignment.

It’s not yet known what may be happening on Uranus’ night side, which is out of view of Hubble.

When Voyager 2 passed by Uranus in 1986 the planet was tipped such that its rotational axis was aimed toward the Sun. This meant that its magnetic axis —  offset by 60 degrees — was angled enough to encounter the solar wind in much the same way that Earth’s does. This created nightside auroras similar to Earth’s that Voyager saw.

By 2011, however, Uranus — which has an 84-year-long orbit — was near equinox and as a result its magnetic axis was nearly perpendicular with its orbital plane, aiming each end directly into the solar wind once a day. This makes for very different kinds of auroras than what was seen by Voyager; in fact, there’s really nothing else like it that astronomers know of.

“This configuration is unique in the solar system,” said Lamy.

Further investigations of Uranus’ auroras and magnetic field can offer insight into the dynamics of Earth’s own magnetosphere and how it interacts with the solar wind, which in turn affects our increasingly technological society.

The team’s paper will be published Saturday in Geophysical Research Letters, a journal of the American Geophysical Union.

Read the release from the AGU here.

Posted on by Nancy Atkinson

Guest Post: Drifting on Alien Winds: Exploring the Skies and Weather of Other Worlds

Triton Probe: Neptune’s blue skies may be visited by beachball-sized methane raindrops. (painting ©Michael Carroll)

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Editor’s note: We all want to explore other worlds in our solar system, but perhaps you haven’t considered the bizarre weather you’d encounter — from the blistering hurricane-force winds of Venus to the gentle methane rain showers of Saturn’s giant moon Titan. Science journalist Michael Carroll has written a guest post for Universe Today which provides peek at the subject matter for his new book, “Drifting on Alien Winds: Exploring the Skies and Weather of Other Worlds.”

It’s been a dramatic year for weather on Earth. Blizzards have blanketed the east coast, crippling traffic and power grids. Cyclone Tasha drenched Queensland, Australia as rainfall swelled the mighty Mississippi, flooding the southern US. Eastern Europe and Asia broke high temperature records. But despite these meteorological theatrics, the Earth’s conditions are a calm echo of the weather on other worlds in our solar system.


Take our nearest planetary neighbor, Venus. Nearly a twin of Earth in size, Venus displays truly alien weather. The hurricane-force Venusian winds are ruled not by water (as on Earth), but by battery acid. Sunlight tears carbon dioxide molecules (CO2) apart in a process called photodissociation. Leftover bits of molecules frantically try to combine with sulfur and water to become chemically stable, resulting acid hazes. Temperatures soar to 900ºF at the surface, where air is as dense as the Earthly oceans at a depth of X feet.

Venus is the poster child of comparative planetology, the study of other planets to help us understand our own. Earth’s simmering sibling has taught us about greenhouse gases, and gave us an even more immediate cautionary tale in 1978. The Pioneer Venus orbiter discovered that Venus naturally generates chlorofluorocarbons (CFCs) in its atmosphere. These CFCs were tearing holes in the planet’s ozone. At the same time, a wide variety of industries were preparing to use CFCs in insecticides, spray paints, and other aerosol products. Venus presented us with a warning that may have averted a planet-wide crisis.

In the same way, Mars has provided insights into long-term climate change. Its weather is a simplified version of our own. Locked within its rocks and polar caps lie records of changing climate over eons.

Jupiter’s Great Red Spot is a cyclone larger than two Earths. (photomontage ©Michael Carroll)

But fans of really extreme weather must venture further out, to the outer planets. Jupiter and Saturn are giant balls of gas with no solid surface, and are known as the “gas giants.” They are truly gigantic: over a thousand Earths could fit within Jupiter itself.

The skies of Jupiter and Saturn are dominated by hydrogen and helium, the ancient building blocks of the solar system. Ammonia mixes in to produce a rich brew of complex chemistry, painting the clouds of Jupiter and Saturn in tans and grays. Lightning bolts sizzle through the clouds, powerful enough to electrify a small city for weeks. Ammonia forms rain and snow in the frigid skies. Jupiter’s Great Red Spot is a centuries-old cyclone large enough to swallow three Earths. Saturn has its own bizarre storms: a vast hexagon-shaped trough of clouds races across the northern hemisphere. Over the south pole, a vast whirlpool gazes from concentric clouds like a Cyclops.

Clouds tower into a twilight sky on Saturn. The planet’s glowing rings seem to bend at the horizon because of the dense air. (painting ©Michael Carroll)

Beyond Jupiter and Saturn lie the “ice giants”, Uranus and Neptune. These behemoths host atmospheres of poisonous brews chilled to cryogenic temperatures. Methane tints Uranus and Neptune blue. Neptune’s clear air reveals a teal cloud deck. Hydrocarbon hazes tinge Uranus to a paler shade of blue-green. Neptune’s clear air is somewhat of a mystery to scientists. This may be because cloud-forming particles can’t stay airborne long enough to become visible clouds. Some scientists propose that Neptune’s abundant methane rains may condense so rapidly that within a few seconds tiny methane raindrops swell to something the size of a beachball. There are no clouds adrift, because methane rains out of the atmosphere too quickly.

One of the strangest cases of bizarre weather comes to us from Neptune’s moon Triton. Triton’s meager nitrogen air is tied to the freezing and thawing of polar ices, also composed of nitrogen. Triton’s entire atmosphere collapses twice a year, when it’s winter on one of the poles. At that time of year, all of Triton’s air migrates to the winter pole, where it freezes to the ground. The moon only has “weather” during the spring and fall; its atmosphere exists only during those seasons.

So, the next time you contemplate complaining about the heat, think of Venus. And if it’s blizzards you worry about, find comfort in Triton: at least our atmosphere doesn’t disappear in winter!

For more on the subject, see Michael Carroll’s newest book, Drifting on Alien Winds: Exploring the Skies and Weather of Other Worlds from Springer.

Posted on by Nancy Atkinson

New Horizons Flies by Uranus

An 'overhead' view of New Horizons' location. Credit: NASA

The Pluto-bound New Horizons spacecraft will fly by another planet today (March 18, 2011). However, the robotic craft won’t be taking any images as it zooms past Uranus’ orbit at about 6 p.m. EDT, 3.8 billion kilometers (2.4 billion miles) away from the gas giant (and 2.0 billion km (1.8 billion miles) from Earth). New Horizons is currently in hibernation mode, and the great distance from Uranus means any observations wouldn’t provide much as far as data and images. But, even so, this event is a ‘landmark’ so to speak in New Horizon’s gauntlet across the solar system.

“New Horizons is all about delayed gratification, and our 9 1/2-year cruise to the Pluto system illustrates that,” said Principal Investigator Alan Stern, of the Southwest Research Institute. “Crossing the orbit of Uranus is another milepost along our long journey to the very frontier of exploration.”

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New Horizons is now well over halfway through its journey to Pluto. Motoring along at 57,900 km/hr (36,000 mph), it will travel more than 4.8 billion km (3 billion miles) to fly past Pluto and its moons Nix, Hydra and Charon in July 2015.

But the journey doesn’t end there. After that, New Horizons will head off to a post-Pluto encounter with other objects within the Kuiper Belt, some event(s) which might take place even into the 2020’s. The planetary science community is working on the selection of potential targets.

The mission still has more than 4 years to go to get to Pluto; it will take 9 nine months to send all the data back to Earth.

The next planetary milestone for New Horizons will be the orbit of Neptune, which it crosses on Aug. 25, 2014, exactly 25 years after Voyager 2 made its historic exploration of that giant planet.

“This mission is a marathon,” says Project Manager Glen Fountain, of the Johns Hopkins University Applied Physics Laboratory. “The New Horizons team has been focused on keeping the spacecraft on course and preparing for Pluto. So far, so good, and we are working to keep it that way.”

Source: New Horizons