How the Sun stole Mars’ atmosphere

The solar wind has made Mars a cold desert, and a tougher environment for would-be colonists. Alan Duffy explains the latest research.

 

Four billion years ago, Mars and Earth were like twins. Water flowed on the Martian surface beneath an atmosphere rich in carbon dioxide, oxygen, methane and water vapour. Today the Martian atmosphere is vanishingly thin, just a hundredth the density of Earth’s, and its surface water has disappeared.

Where did it all go? To find out NASA sent MAVEN – the Mars Atmosphere and Volatile Evolution spacecraft – all decked out with sensitive new instruments. It’s been orbiting the planet since last September and this November it finally answered the riddle. The solar wind blew away the Martian atmosphere. This result was the highlight of a landslide of papers published in November using data collected by MAVEN – four inScience and 40 in Geophysical Research Letters.

The first hints water used to flow on Mars came from NASA’s Viking missions in the 1970s. The orbiters beamed back pictures of valleys that looked like they’d been carved by ancient rivers. More recent landers showed fossilised ripples of lakebeds and streams known as mudstone. And just in September, instruments on the Mars Reconnaissance Orbiter detected the signatures of hydrated salts streaking down crater edges. The briny residue showed water may still be found occasionally on the surface of Mars. But it’s a drop in the ocean compared to the bodies of water that resided in the ancient lakes some four billion years ago.

Billions of years ago when the Red Planet was young, it appears to have had a thick atmosphere that was warm enough to support oceans of liquid water – a critical ingredient for life. This animation shows what Mars might have looked like at the time, before transitioning to the dusty red planet we see today.

So where did the water go? Some thought it was locked away in subsurface ice deposits. And as for the atmosphere, carbon dioxide and other gases might have chemically reacted with rocks over hundreds of millions of years, and become locked away inside Mars’ geology – similar to the way carbon dioxide in Earth’s atmosphere can get locked away as limestone.

The other possibility was that both had been lost to space: first the atmosphere, then the water, which in the thin air would simply have evaporated away. If this theory was right, the real question was, why did the atmosphere vanish in the first place? It shouldn’t have: Mars’ gravity, a third of Earth’s, is sufficiently strong to keep its atmosphere.

“Like the theft of a few coins from a cash register every day,

the loss becomes significant over time”

First off, MAVEN established that the Martian atmosphere was indeed vanishing into space. Dipping in and out of the Red Planet’s upper atmosphere, it detected wisps of ionised air escaping at the rate of about 100 grams each second. “Like the theft of a few coins from a cash register every day, the loss becomes significant over time,” says Bruce Jakosky, MAVEN principal investigator at the University of Colorado, Boulder.

MAVEN was also present when a solar storm hit Mars in March 2015.

The rate of atmospheric loss increased up to 20-fold when the storm struck. The storm was the result of a coronal mass ejection by the Sun, which hurled billions of tonnes of superhot material into space. Unlike the constant, steady stream of particles of the solar wind, these events are far more energetic and damaging. With each direct hit, more of the Martian atmosphere is lost.

The Sun had been caught in the act of planetary vandalism. MAVEN’s data showed the long suspected culprit, the solar wind (and its sometime partner in crime, solar storms), was easily capable of removing an atmosphere. While the Sun is still at work shearing away the Martian atmosphere today, four billion years ago a youthful Sun was even more tempestuous with storms that were more frequent and powerful than those of today.

So why was Earth spared this fate? Our planet is blessed with a magnetic shield that deflects the charged solar particles; Mars is not. A magnetic shield is created by a churning liquid iron core, which Earth has. Mars once had a molten core too but around four billion years ago, it cooled and solidified. Just why we have been spared this fate is not entirely understood – perhaps it is simply because Mars is smaller and lost heat more quickly. The same fate undoubtedly awaits Earth too, but not for many millions (if not billions) of years yet.

Without a liquid iron core, Mars’ magnetic field faded away. The solar wind then ripped away most of the atmosphere, leaving the oceans to evaporate into space. But the removal of its atmosphere would have taken place over a few hundred million years, so any life that existed had time to adapt to living underground; the Sun’s ultraviolet radiation would be fatal to life on the surface.

For the first time, NASA’s MAVEN spacecraft has observed the solar winds in action stripping away Mars’ atmosphere. This video shows a simulation of the solar wind striking Mars, then adds a colourful overlay of Mars’ atmosphere being removed (the new measurements taken by MAVEN).

This is good news for scientists hoping to find life on Mars, but bad news for human colonists.

Some had hoped the gases that made up the atmosphere might still be present beneath the surface, awaiting our arrival to unlock all that carbon dioxide, begin to grow plants and terraform the Red Planet. Not so: at least as far as the atmosphere goes, colonisers will need to bring their own.

Source: How the Sun stole Mars’ atmosphere

Advertisements
How the Sun stole Mars’ atmosphere

PLUTO HAS RED ICE AND BLUE SKIES

Pluto’s blue haze

NASA/JHUAPL/SwRI

After New Horizons sped past Pluto in July, the spacecraft turned around to look at the dwarf planet’s silhouette against the sun. The backlighting gave New Horizons some insight into the planetoid’s atmosphere, and now the first color images of the haze has revealed that Pluto’s skies are partially blue.

If you were standing on Pluto, the sky would probably actually look reddish gray, though Miriam Kramer at Mashable reports that sunrise and sunset on Pluto could have a blue hue. The way the atmospheric particles are scattering blue light is a surprise to the New Horizons scientists. It also tells them a thing or two about the composition of the atmosphere.

“That striking blue tint tells us about the size and composition of the haze particles,” said New Horizons’ Carly Howett in a press release. “A blue sky often results from scattering of sunlight by very small particles. On Earth, those particles are very tiny nitrogen molecules. On Pluto they appear to be larger–but still relatively small–soot-like particles we call tholins.”

Tholins are simple organic molecules. Scientists think Pluto’s tholins come from ultraviolet light breaking up the methane and nitrogen in the atmosphere. Those reactive particles then combine together into complex molecules. Volatile gases condense on the molecules, making them heavy enough to rain down on Pluto. This is where Pluto gets its reddish-brown tint.

A second image, released today, shows the distribution of water ice across part of Pluto’s surface. Water ice in itself is not a surprise–scientists suspected the planetoid’s mountain ranges are made of ice. Still, there are only a few places where Pluto’s water ice isn’t buried in more volatile ices, such as those made from nitrogen and methane.

Map of exposed ice on Pluto’s surface

NASA/JHUAPL/SwRI

What’s more, these water ices seem to be reddish in color, based on color maps from New Horizons.

“I’m surprised that this water ice is so red,” says Silvia Protopapa, another New Horizons team member. “We don’t yet understand the relationship between water ice and the reddish tholin colorants on Pluto’s surface.”

Source: PLUTO HAS RED ICE AND BLUE SKIES

PLUTO HAS RED ICE AND BLUE SKIES

A Canadian start-up is removing CO2 from the air and turning it into pellets

A pilot project to suck CO2 out of the atmosphere and turn it into pellets that can either be used as fuel or stored underground for later has been launched by a Calgary-based start-up called Carbon Engineering.

While the test facility has so far only extracted 10 tonnes of CO2 since its launch back in June, its operations will help inform the construction of a $200 million commercial plant in 2017, which is expected to extract 1 million tonnes per day – the equivalent of taking 100 cars off the road every year. It plans to start selling CO2-based synthetic fuels by 2018.

“It’s now possible to take CO2 out of the atmosphere, and use it as a feed stock, with hydrogen, to produce net zero emission fuels,” company chief executive Adrian Corless told the AFP.

Funded by private investors, including billionaires Bill Gates and oil sands financier Murray Edwards, Carbon Engineering is not the only company in the world intent on solving our carbon dioxide problems, but it claims to be the first to demonstrate how its technology can be scaled up to have both an actual environmental impact and commercial potential.

Instead of tackling the CO2 that pours out of factory smokestacks – because there are existing machines that do this pretty well – the Carbon Engineering ‘direct air capture plant’ will deal with everyday carbon emissions from buildings, transportation, and agriculture. “Emissions from sources you just can’t otherwise capture,” Corless says.

“It’s still a pilot-scale plant,” he told CBC News. “But it’s very important, because it’s the first time that anyone’s demonstrated a technology that captures CO2 that has the potential to be scaled up to be large enough to be relevant from an environmental or climate point of view.”

As we reported back at the time of the test plant launch, direct air capture works just like these new solar cells that split water into a hydrogen fuel – the CO2 recycling plant extracts CO2 from the air using a giant complex of fans, and combines this with liquid hydrogen split from water. This mixture can then be converted into solid pellets of calcium carbonate, and either heated to between 800 and 900 degrees Celsius to release pure carbon for use as fuel, or stored for later.

CEProcessCarbon Engineering


According to CBC News,
the larger plant should be able to produce up to 400 litres of gasoline or diesel per day using this method. One of the main things it has going for it is that because it turns the CO2 into fuel, no change in infrastructure will be needed to power big fuel-guzzlers such as ships, planes, and long-haulage trucks. Even existing petrol pumps can work with the fuel. A major limitation of solar and wind technologies, on the other hand, is that they require specific technologies to capture and disperse energy.

“The nice thing about the technology is that there are no real limitations for it to ultimately, in theory, displace all of the existing fossil-based transportation fuels,”Corless said.

Going forward, the most important thing for Carbon Engineering to figure out is how to be commercially viable. As Kesavan Unnikrishnan points out at Digital Journal, carbon can cost anything from $1/tonne (Mexico and Poland) to $130/tonne (Sweden) around the world, and Carbon Engineering will need to sell its product at around $100/tonne to support itself commercially.

We’ll have to wait and see how things go for direct air capture in the future, but we’re so excited by its potential. Watch the video below to find out more about how it works:

Source: A Canadian start-up is removing CO2 from the air and turning it into pellets

A Canadian start-up is removing CO2 from the air and turning it into pellets

EarthSky’s meteor shower guide for 2015

The Delta Aquarid meteor shower – which always happens in late July and early August – is going on now, but bright moonlight is interfering. Click here for more about the Delta Aquarids. This shower overlaps with the famous Perseid meteor shower, which will peak on the mornings of August 11, 12 and 13. It’s going to be a wonderful year for the Perseids! The moon is out of the way. Click here for more about the Perseids. And follow the links below to learn what to expect for meteor showers during the rest of 2015.

January 3-4, 2015 Quadrantids

April 22-23, 2015 Lyrids

May 5-6, 2015 Eta Aquarids

July 28-29, 2015 Delta Aquarids

August 12-13, 2015 Perseids

October 8, 2015 Draconids

October 21-22, 2015 Orionids

November 4-5, 2015 South Taurids

November 12-13, 2015 North Taurids

November 17-18, 2015 Leonids

December 13-14, 2015 Geminids

A word about moonlight

Most important: a dark sky

Know your dates and times

Where to go to watch a meteor shower

What to bring with you

Are the predictions reliable?

Remember …

View larger. | Scott MacNeill created this wonderful composite image at Frosty Drew Observatory in Charlestown, Rhode Island, USA.  We love this image, because you can see the meteors coming from their radiant point in the constellation Perseus.  Thank you, Scott!

January 4, 2015 before dawn, the Quadrantids

Although the Quadrantids can produce over 100 meteors per hour, the sharp peak of this shower tends to last only a few hours, and doesn’t always come at an opportune time. In other words, you have to be in the right spot on Earth to view this meteor shower in all its splendor. The radiant point is in the part of the sky that used to be considered the constellation Quadrans Muralis the Mural Quadrant. You’ll find this radiant near the famous Big Dipper asterism (chart here), in the north-northeastern sky after midnight and highest up before dawn. Because the radiant is fairly far to the north on the sky’s dome, meteor numbers will be greater in the Northern Hemisphere. In 2015, watch in the wee hours – after midnight and before dawn – on January 4. Unfortunately, the almost-fullwaxing gibbous moon is out almost all night long, sitting low in the west in the dark hour before dawn.Click here to find out your moonset time..

Everything you need to know: Quadrantid meteor shower

Around the March equinox … fireball season. A fireball is just an especially bright meteor. Northern spring and southern autumn – for a few weeks around the March equinox – is a good time to see one. It’s fireball season — a time of year when bright meteors appear in greater numbers than usual. In fact, in the weeks around the equinox, the appearance rate of fireballs can increase by as much as 30 percent, says NASA.

April 22 and 23, 2015 before dawn, the Lyrids
The Lyrid meteor shower – April’s shooting stars – lasts from about April 16 to 25. Lyrid meteors tend to be bright and often leave trails. About 10-20 meteors per hour can be expected at their peak. Plus, the Lyrids are known for uncommon surges that can sometimes bring the rate up to 100 per hour. Those rare outbursts are not easy to predict, but they’re one of the reasons the tantalizing Lyrids are worth checking out around their peak morning. The radiant for this shower is near the bright star Vega in the constellation Lyra (chart here), which rises in the northeast at about 10 p.m. on April evenings.In 2015, the peak morning is April 23. Watch also on the morning of April 22. And you might also see Lyrid meteors before and after that date. The waxing crescent moon will set in the evening, leaving a dark for watching this year’s Lyrid shower.

Everything you need to know: Lyrid meteor shower

May 6, 2015 before dawn, the Eta Aquarids
This meteor shower has a relatively broad maximum – meaning you can watch it for several days around the predicted peak. However, in 2015, the bright waning gibbous moon is sure to diminish the numbers. The radiant is near the star Eta in the constellation Aquarius the Water Bearer (click here for chart). The radiant comes over the eastern horizon at about 4 a.m. local time; that is the time at all locations across the globe. For that reason, the hour or two before dawn tends to offer the most Eta Aquarid meteors, no matter where you are on Earth. At northerly latitudes – like those in the northern U.S. and Canada, or northern Europe, for example – the meteor numbers are typically lower for this shower. In the southern half of the U.S., 10 to 20 meteors per hour might be visible in a dark sky. Farther south – for example, at latitudes in the Southern Hemisphere – the meteor numbers may increase dramatically, with perhaps two to three times more Eta Aquarid meteors streaking the southern skies. For the most part, the Eta Aquarids is a predawn shower. In 2015, the bright waning gibbous moon will obscure this year’s production. The most meteors will probably rain down on May 6, in the dark hours before dawn. But watch on May 5 and 7 as well! The broad peak to this shower means that some meteors may fly in the dark hour before dawn for a few days before and after the predicted optimal date.

Everything you need to know: Eta Aquarid meteor shower

Late July and early August, 2015, the Delta Aquarids
Like the Eta Aquarids in May, the Delta Aquarid meteor shower in July favors the Southern Hemisphere and tropical latitudes in the Northern Hemisphere. The meteors appear to radiate from near the star Skat or Delta in the constellation Aquarius the Water Bearer. The maximum hourly rate can reach 15-20 meteors in a dark sky. The nominal peak is around July 27-30, but, unlike many meteor showers, the Delta Aquarids lack a very definite peak. Instead, these medium-speed meteors ramble along fairly steadily throughout late July and early August. An hour or two before dawn usually presents the most favorable view of the Delta Aquarids. At the shower’s peak in late July, 2015, the rather faint Delta Aquarid meteors will have to contend with moonlight. The waxing gibbous moon will be out until the wee hours after midnight. Try watching in late July predawn sky, after moonset.

Everything you need to know: Delta Aquarid shower

August 12-13, 2015 before dawn, the Perseids
The Perseid meteor shower is perhaps the most beloved meteor shower of the year for the Northern Hemisphere. Fortunately, the slender waning crescent moon rising at or near dawn will not obtrude on this year’s shower. The Perseid shower builds gradually to a peak, often produces 50 to 100 meteors per hour in a dark sky at the peak, and, for us in the Northern Hemisphere, this shower comes when the weather is warm. The Perseids tend to strengthen in number as late night deepens into midnight, and typically produce the most meteors in the wee hours before dawn. They radiate from a point in the constellation Perseus the Hero, but, as with all meteor shower radiant points, you don’t need to know Perseus to watch the shower; instead, the meteors appear in all parts of the sky. They are typically fast and bright meteors. They frequently leave persistent trains. Every year, you can look for the Perseids to peak around August 10-13. Predicted peak mornings in 2015: August 11, 12 and 13. The Perseids combine with the Delta Aquarid shower (above) to produce a dazzling display of shooting stars on what are, for us in the N. Hemisphere, warm summer nights. In 2015, as always, the Perseid meteors will be building to a peak from early August until the peak nights; afterwards, they drop off fairly rapidly. With little or no moon to ruin the show, this is a great year for watching the Perseid meteor shower.

Everything you need to know: Perseid meteor shower

October 8, 2015, the Draconids
The radiant point for the Draconid meteor shower almost coincides with the head of the constellation Draco the Dragon in the northern sky. That’s why the Draconids are best viewed from the Northern Hemisphere. The Draconid shower is a real oddity, in that the radiant point stands highest in the sky as darkness falls. That means that, unlike many meteor showers, more Draconids are likely to fly in the evening hours than in the morning hours after midnight. This shower is usually a sleeper, producing only a handful of languid meteors per hour in most years. But watch out if the Dragon awakes! In rare instances, fiery Draco has been known to spew forth many hundreds of meteors in a single hour. In 2015, the waning crescent moon rises at late night and will not intrude on this year’s Draconid shower. Try watching at nightfall and early evening on October 8 and 9.

Everything you need to know: Draconid Meteor shower

October 22, 2015 before dawn, the Orionids
On a dark, moonless night, the Orionids exhibit a maximum of about 10 to 20 meteors per hour. The waxing gibbous moon will be out the during the evening hours, but it’ll set before the prime time viewing hours, providing deliciously dark skies for this year’s Orionid shower. More meteors tend to fly after midnight, and the Orionids are typically at their best in the wee hours before dawn. These fast-moving meteors occasionally leave persistent trains. They sometimes produce bright fireballs, so watch for them to flame in the sky. If you trace these meteors backward, they seem to come from the Club of the famous constellation Orion the Hunter. You might know Orion’s bright, ruddy star Betelgeuse. The radiant is north of Betelgeuse. The Orionids have a broad and irregular peak that isn’t easy to predict. This year, 2015, presents a fine year for watching the Orionid meteor shower. The best viewing for the Orionids in 2015 will probably be before dawn on October 22. Try the days before and after that, too, sticking to the midnight-to-dawn hours..

Everything you need to know: Orionid meteor shower

Late night November 4 until dawn November 5, 2015, the South Taurids
Fortunately, the full moon will wash away all but the brightest South Taurid meteors. The meteoroid streams that feed the South (and North) Taurids are very spread out and diffuse. That means the Taurids are extremely long-lasting (September 25 to November 25) but usually don’t offer more than about 7 meteors per hour. That is true even on the South Taurids’ expected peak night. The Taurids are, however, well known for having a high percentage of fireballs, or exceptionally bright meteors. Plus, the other Taurid shower – the North Taurids – always adds a few more meteors to the mix during the South Taurids’ peak night. In 2015, the slim waning crescent moon coming up before dawn will not seriously obtrude on this year’s South Taurid meteor shower. The South Taurids should produce their greatest number of meteors in the wee hours – between midnight and dawn – on November 5. Remember, it’ll be possible to catch a fireball or two!

Late night November 12 until dawn November 13, 2015, the North Taurids
Like the South Taurids, the North Taurids meteor shower is long-lasting (October 12 – December 2) but modest, and the peak number is forecast at about 7 meteors per hour. The North and South Taurids combine, however, to provide a nice sprinkling of meteors throughout October and November. Typically, you see the maximum numbers at around midnight, when Taurus the Bull is highest in the sky. Taurid meteors tend to be slow-moving, but sometimes very bright. In 2015, the new moon comes only one day before the predicted peak, providing a dark sky for the 2015 North Taurid shower.

Late night November 17 until dawn November 18, 2015, the Leonids
Radiating from the constellation Leo the Lion, the famous Leonid meteor shower has produced some of the greatest meteor storms in history – at least one in living memory, 1966 – with rates as high as thousands of meteors per minute during a span of 15 minutes on the morning of November 17, 1966. Indeed, on that beautiful night in 1966, the meteors did, briefly, fall like rain. Some who witnessed the 1966 Leonid meteor storm said they felt as if they needed to grip the ground, so strong was the impression of Earth plowing along through space, fording the meteoroid stream. The meteors, after all, were all streaming from a single point in the sky – the radiant point – in this case in the constellation Leo the Lion. Leonid meteor storms sometimes recur in cycles of 33 to 34 years, but the Leonids around the turn of the century – while wonderful for many observers – did not match the shower of 1966. And, in most years, the Lion whimpers rather than roars, producing a maximum of perhaps 10-15 meteors per hour on a dark night. Like many meteor showers, the Leonids ordinarily pick up steam after midnight and display the greatest meteor numbers just before dawn. In 2015, the rather wide waxing crescent moon sets in the evening and won’t interfere with this year’s Leonid meteor shower. The peak morning will probably be November 18 – but try November 17, too.

Everything you need to know: Leonid meteor shower

December 13-14, 2015, mid-evening until dawn, Geminids
Radiating from near the bright stars Castor and Pollux in the constellation Gemini the Twins, the Geminid meteor shower is one of the finest meteors showers visible in either the Northern or the Southern Hemisphere. Best yet, there is no moon to obscure the 2015 Geminid shower. The meteors are plentiful, rivaling the August Perseids, with perhaps 50 to 100 meteors per hour visible at the peak. Plus Geminid meteors are often bright. These meteors are often about as good in the evening as in the hours between midnight and dawn. In 2015, the slender waxing crescent moon will set soon after the sun, providing a wonderful cover of darkness for the Geminid meteor shower. Your best bet is to watch on December 12-13 and 13-14, from mid-evening (9 to 10 p.m.) until dawn.

Animation Credit: NASA MSFC

A word about moonlight. In 2015, moonlight will not pose much of a problem for the April Lyrids, August Perseids, October Draconids, October Orionids, November South Taurids, November North Taurids, November Leonids and December Geminids. There’s some moon-free viewing time for the July Delta Aquarids. The nearly full moon gets in the way of the January Quadrantids and May Eta Aquarids. Our almanac page provides links for access to the moonrise and moonset times in your sky.

Most important: a dark sky. Here’s the first thing – the main thing – you need to know to become as proficient as the experts at watching meteors. That is, to watch meteors, you need a dark sky. It’s possible to catch a meteor or two or even more from the suburbs. But, to experience a true meteor shower – where you might see several meteor each minute – avoid city lights.

Know your dates and times. You also need to be looking on the right date, at the right time of night. Meteor showers occur over a range of dates, because they stem from Earth’s own movement through space. As we orbit the sun, we cross “meteor streams.” These streams of icy particles in space come from comets moving in orbit around the sun. Comets are fragile icy bodies that litter their orbits with debris. When this cometary debris enters our atmosphere, it vaporizes due to friction with the air. If moonlight or city lights don’t obscure the view, we on Earth see the falling, vaporizing particles as meteors. The Lyrids take place between about April 16 and 25. The peak morning in 2015 should be April 22, but you might catch Lyrid meteors on the nights around that date as well.

Where to go to watch a meteor shower. You can comfortably watch meteors from many places, assuming you have a dark sky: a rural back yard or deck, the hood of your car, the side of a road. State parks and national parks are good bets, but be sure they have a wide open viewing area, like a field; you don’t want to be stuck in the midst of a forest on meteor night. An EarthSky friend and veteran meteor-watcher and astrophotographer Sergio Garcia Rill also offers this specific advice:

… you might want to give it a try but don’t know where to go. Well, in planning my night photoshoots I use a variety of apps and web pages to know how dark the sky is in a certain location, the weather forecast, and how the night sky will look. Here’s the link toDark Sky Finder. It’s a website that shows the light pollution in and around cities in North America which has been fundamental for finding dark sites to setup shots. Dark Sky finder also has an app for iPhone and iPad which as of this writting is only 99 cents so you might want to look into that as well. For people not in North America, the Blue Marble Navigator might be able to help to see how bright are the lights near you.

The other tool I can suggest is the Clear Sky Chart. I’ve learned the hard way that, now matter how perfectly dark the sky is at your location, it won’t matter if there’s a layer of clouds between you an the stars. This page is a little hard to read, but it shows a time chart, with each column being an hour, and each row being one of the conditions like cloud coverage and darkness. Alternatively, you could try to see the regular weather forecast at the weather channel or your favorite weather app.

What to bring with you. You don’t need special equipment to watch a meteor shower. If you want to bring along equipment to make yourself more comfortable, consider a blanket or reclining lawn chair, a thermos with a hot drink, binoculars for gazing at the stars. Be sure to dress warmly enough, even in spring or summer, especially in the hours before dawn. Binoculars are fun to have, too. You won’t need them for watching the meteor shower, but, especially if you have a dark sky, you might not be able to resist pointing them at the starry sky.

Are the predictions reliable? Although astronomers have tried to publish exact predictions in recent years, meteor showers remain notoriously unpredictable. Your best bet is to go outside at the times we suggest, and plan to spend at least an hour, if not a whole night, reclining comfortably while looking up at the sky. Also remember that meteor showers typically don’t just happen on one night. They span a range of dates. So the morning before or after a shower’s peak might be good, too.

Remember … meteor showers are like fishing. You go, you enjoy nature … and sometimes you catch something.

Peak dates are derived from data published in the Observer’s Handbook by the Royal Astronomical Society of Canada and Guy Ottewell’s Astronomical Calendar.

Dick Dionne in Green Valley, Arizona caught this bright Taurid fireball on November 15, 2014.  Many reported fireballs in early November this year!

EarthSky Facebook friend Eddie Popovits caught this Perseid fireball in early August 2014.

Eta Aquarid meteor captured on May 6, 2014 by Mike Taylor.  Visit Taylor Photography.

View larger. | Simon Waldram in the Canary Islands caught this Lyrid meteor on the night of April 20-21, 2014.  Thank you, Simon!

Mike O'Neal posted this on the EarthSky Facebook page today (April 22).  He wrote, 'Had mostly cloudy sky, but did see some beautiful ones between the breaks.'

A North Taurid meteor seen fleeing its radiant point near the Pleiades in the constellation Taurus.  Captured by EarthSky Facebook friend Abhijit Juvekar on November 12, 2013.  Thank you, Abhijit!

View larger. | Scott MacNeill created this wonderful composite image at Frosty Drew Observatory in Charlestown, Rhode Island, USA.  We love this image, because you can see the meteors coming from their radiant point in the constellation Perseus.  Thank you, Scott!

Eta Aquarid meteor seen by EarthSky Facebook friend Ann Dinsmore on the morning of May 5, 2013.  View larger.  Thanks Ann!

From EarthSky Facebook friend Guy Livesay. He wrote, ' Didn't see many Lyrids on the 21st or 22nd in Eastern NC. This is from the 21st. There's actually 2 in this shot very close together.'

Bottom line: The Lyrid meteor shower is next on the mornings of April 22 and 23. April 23 will probably have more meteors. Details on how to watch, plus listings of all major meteor showers in 2015.

EarthSky’s top 10 tips for meteor-watchers

 Source:  EarthSky’s meteor shower guide for 2015

EarthSky’s meteor shower guide for 2015

Why we live on Earth and not Venus

Compared to its celestial neighbours Venus and Mars, Earth is a pretty habitable place. So how did we get so lucky? A new study sheds light on the improbable evolutionary path that enabled Earth to sustain life.

The research, published this week in Nature Geoscience, suggests that Earth’s first crust, which was rich in radioactive heat-producing elements such as uranium and potassium, was torn from the planet and lost to space when asteroids bombarded the planet early in its history. This phenomenon, known as impact erosion, helps explain a landmark discovery made over a decade ago about the Earth’s composition.

Researchers with the University of British Columbia and University of California, Santa Barbara say that the early loss of these two elements ultimately determined the evolution of Earth’s plate tectonics, magnetic field and climate.

“The events that define the early formation and bulk composition of Earth govern, in part, the subsequent tectonic, magnetic and climatic histories of our planet, all of which have to work together to create the Earth in which we live,” said Mark Jellinek, a professor in the Department of Earth, Ocean & Atmospheric Sciences at UBC. “It’s these events that potentially differentiate Earth from other planets.”

On Earth, shifting tectonic plates cause regular overturning of Earth’s surface, which steadily cools the underlying mantle, maintains the planet’s strong magnetic field and stimulates volcanic activity. Erupting volcanoes release greenhouse gases from deep inside the planet and regular eruptions help to maintain the habitable climate that distinguishes Earth from all other rocky planets.

Venus is the most similar planet to Earth in terms of size, mass, density, gravity and composition. While Earth has had a stable and habitable climate over geological time, Venus is in a climate catastrophe with a thick carbon dioxide atmosphere and surface temperatures reaching about 470 C. In this study, Jellinek and Matt Jackson, an associate professor at the University of California, explain why the two planets could have evolved so differently.

“Earth could have easily ended up like present day Venus,” said Jellinek. “A key difference that can tip the balance, however, may be differing extents of impact erosion.”

With less impact erosion, Venus would cool episodically with catastrophic swings in the intensity of volcanic activity driving dramatic and billion-year-long swings in climate.

“We played out this impact erosion story forward in time and we were able to show that the effect of the conditions governing the initial composition of a planet can have profound consequences for its evolution. It’s a very special set of circumstances that make Earth.”

Story Source:

The above post is reprinted from materials provided by University of British ColumbiaNote: Materials may be edited for content and length.


Journal Reference:

  1. A. M. Jellinek, M. G. Jackson. Connections between the bulk composition, geodynamics and habitability of EarthNature Geoscience, 2015; DOI: 10.1038/ngeo2488
Why we live on Earth and not Venus

New CO2 recycler captures carbon dioxide from the atmosphere and turns it back into fuel

British Columbia start-up, Carbon Engineering is now developing technology to suck the carbon dioxide out of the atmosphere and save it for fuel and other applications.

It works similar to trees, but can be implemented on land unable to host tree growth, like deserts and ice.  The carbon dioxide can be processed with hydrogen, captured from water, and combined to form hydrocarbons in the way of jet fuel and gasoline, which can then be reused. The carbon dioxide is released back into the atmosphere when it’s burned and captured again in a self sustaining process, powered by renewable energy.

The company is currently constructing the “wet end” of their demo plant.  This is the part that circulates liquid to scrub CO2 from the air and concentrates the product in solid calcium carbonate pellets.

Source: New CO2 recycler captures carbon dioxide from the atmosphere and turns it back into fuel 

New CO2 recycler captures carbon dioxide from the atmosphere and turns it back into fuel

#DSCOVR today’s new image of #Earth. What made the Blue Marble so special? #EarthRightNow

It was the first full photo of the Earth, taken on December 7, 1972, by the American crew of the Apollo 17 spacecraft. The original Blue Marble is thought by many to be the most-reproduced image of all time.

What made the Blue Marble so special? Sure, it might have been the first full photo of the Earth that we took, but we’ve taken a bunch more since then.

Like this one.

And this one.

And this one.

So why is the “Blue Marble” a bigger deal than these? Turns out, it’s quite tricky to take a good photo of the entire Earth.

The first challenge is that our planet is big. The only way to view all of it at once is to get much farther away from the Earth than we do for many of our activities in outer space. The International Space Station, for instance, orbits at a height of just 400 kilometers, or about 249 miles away from Earth.

The second problem is a familiar one that plagues many photographers who are Earthbound: lighting. In order to view the Earth as a fully illuminated globe, a person (or camera) must be situated in front of it, with the sun directly at his or her back. Not surprisingly, it can be difficult to arrange this specific lighting scheme for a camera-set up that’s orbiting in space at speeds approaching thousands of miles per hour.

As a result of these challenges, NASA, NOAA, and other science agencies most often rely on composite images to depict our planet. These images stitch together multiple high-resolution snapshots taken by satellites already in orbit to produce one seamless portrait of the Earth. And that’s what the three photos above are: composite images produced by NASA over the past fifteen years (released respectively in 2002, 2007, and 2012).

Composite imaging is an extremely useful tool for helping people understand the Earth — they allow researchers to capture certain features at higher resolution; reduce the obscuring effect of cloud coverage in certain areas; and overlay various data layers to help identify patterns and trends. Composites can result in some truly remarkable images, like this “Black Marble,” which, by stitching together multiple views of the planet, shows a full global view of the Earth’s city lights.

But there’s something remarkable about a single snapshot of the Earth — an intact view of our planet in its entirety, hanging in space.

Apollo 17 astronaut Eugene Cernan explained:

“…you’re looking at the most beautiful star in the heavens — the most beautiful because it’s the one we understand and we know, it’s home, it’s people, family, love, life — and besides that it is beautiful. You can see from pole to pole and across oceans and continents and you can watch it turn and there’s no strings holding it up, and it’s moving in a blackness that is almost beyond conception.”

That’s why today, I am excited to see that NASA has released its new Blue Marble, the first of many more to come later this year.

This Blue Marble is the first fully illuminated snapshot of the Earth captured by the DSCOVR satellite, a joint NASA, NOAA, and U.S. Air Force mission. After launching in February 2015, DSCOVR spent months rocketing away from Earth before reaching its final orbit position in June 2015 at Lagrange point 1 (L1), about one million miles away from Earth. (A Lagrange point, in case you were wondering, is “a position where the gravitational pull of two large masses precisely equals the centripetal force required for a small object to move with them.” For our purposes, that means that a Lagrange point is a spot at which a satellite can maintain a fixed position relative to the Earth.)

DSCOVR just after launch.

The DSCOVR mission serves several important purposes, including providing scientific data on heat and radiation fluxes across the Earth’s atmosphere, and maintaining the nation’s ability to provide timely alerts and forecasts for space weather events, which can disrupt telecommunications capabilities, power grids, GPS applications, and other systems vital to our daily lives and national and local economies.

And with its Earth Polychromatic Imaging Camera (which has an epic acronym. Seriously. It’s EPIC), DSCOVR will capture and transmit full images of the Earth every few hours! The information gathered by EPIC will help us examine a range of Earth properties, such as ozone and aerosol levels, cloud coverage, and vegetation density, supporting a number of climate science applications.

One of the best parts of this mission is that NASA will make all of the data, data products, and images collected by DSCOVR freely available to the public, including the new “Blue Marble” images. Starting soon, you’ll be able to view and download new “Blue Marble” images taken by DSCOVR every day.

In addition to providing useful data to scientists and researchers, these images will remind all of us that we live on a planet, in a solar system, in a universe. And that we are not just Americans, but citizens of Earth.

Source: A New Blue Marble

#DSCOVR today’s new image of #Earth. What made the Blue Marble so special? #EarthRightNow