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EarthSky by Eleanor Imster - 20m ago

Fotograf Göran Strand captured this image on July 19, 2019. He wrote:

Of all different weather types, thunder and lightning is one of my favorite. Not just for the spectacular show, but also for the difficulty in photographing lightning during daytime.

I’ve done this for several years now but this is perhaps my best lightning photo so far. I always strive for interesting content in the photo, and this makes things a bit harder. But in this case I got lucky to catch a really beautiful lightning over a small harbor and the entire lighting was visible in the frame.

Thanks Göran!

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Unless you’re a night owl, you’re not likely to see the moon and the planet Uranus before your bedtime in late July 2019. They’ll come up in the east more or less together around the midnight hour, and then will climb upward during the early morning dark hours. Visit the Sunrise Sunset Calendars site to know when dawn’s first light comes to your sky, remembering to check the box for astronomical twilight. The moon and Uranus soar highest up for the night just before dawn’s first light.

So the dark hour before dawn finds Uranus highest in the sky and easiest to spot in late July 2019. Uranus is the seventh planet outward from our sun, and it’s theoretically visible to the eye. But it’s not one of the bright planets, and you’ll surely need a dark sky – probably optical aid – and a good sky chart to see this faint world.

Once you spot it, do try to see it with the eye alone. People with exceptional eyesight can see Uranus as a dim speck of light on a dark, moonless night.

This artist’s concept depicts the relative sizes of the planets. Jupiter’s diameter is about 11 times that of Earth whereas Uranus’ diameter is about 4 times greater.

By the way, the moon will be at its last quarter phase on July 25, 2019, at 01:18 UTC. A last quarter moon rises around midnight, appearing with half its lunar disk lit by sunshine (daytime on the moon), while the other half is engulfed in the moon’s own shadow (nighttime on the moon). The lunar terminator – or shadow line dividing the lunar day from the lunar night – shows you where it’s sunset on the waning moon.

Three quarters of the way into its orbital cycle, the moon is in third or last quarter, rising roughly at midnight and setting at roughly noon the following day.

The moon will be slightly past its last quarter phase when it passes 5 degrees (10 moon diameters) south of Uranus on July 25, 2019, at about 7 Universal Time (3 a.m. EDT, 2 a.m. CDT, 1 a.m. MDT and 12 midnight PDT).

Uranus sits in front of the rather faint constellation Aries the Ram. Despite the lunar glare, you might be able to make out Aries’ brightest star, Hamal. Once you become familiar with Hamal, this modestly-bright 2nd-magnitude star will help you locate Aries when the moon has left this area of the sky.

A good familiarity with Aries is your ticket to star-hopping to Uranus, using a sky chart such as this one. Uranus is difficult to see with the eye alone, but quite easy to view with binoculars. Even so, Uranus looks like a dim star, and you need a telescope magnifying Uranus by 100 times or more to discern this planet as a tiny disk instead of a star.

Sky chart via IAU. Uranus is now in front of the constellation Aries the Ram.

Although the moon and Uranus are fairly close together on the sky’s dome in the morning nighttime hours on July 25, 2019, these two worlds are nowhere near one another in space. Uranus lies way out there, at better than 7,500 times the moon’s distance from us. Visit unitarium.com to know the moon’s present distance and Heavens Above for Uranus’ present distance in astronomical units.

Bottom line: Before sunrise on July 25, 2019, you’ll find the moon at or near its last quarter phase and in the vicinity of the 7th planet, Uranus.

Read more: Hubble Sets Its Sights on the Ice Giants, via SkyandTelescope.com

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EarthSky by Deborah Byrd - 6h ago

Tonight … if you have a dark sky, make your acquaintance with the constellation Draco the Dragon, starting at nightfall. At mid-northern latitudes, Draco is a circumpolar constellation, meaning it is out all night long every night of the year. Northern Hemisphere summer evenings are the best time to look, because this is when the Dragon’s flashing eyes look down upon you from up high in the northern sky.

The chart at the top of this post – showing Draco – covers a lot more sky than our charts usually do. That’s because Draco is big! This serpentine star figure wanders in between the Big and Little Dippers, with its tail found between the bowl of the Big Dipper and the star Polaris.

I always notice the two stars in the Dragon’s head when looking at the bright star Vega in the constellation Lyra. If you’re familiar with the Summer Triangle, draw an imaginary line from the star Altair through the star Vega to find the Dragon’s eyes glaring at you from high overhead on July and August evenings. These two stars are Rastaban and Eltanin – lovely, romantic names for the Dragon’s stars.

Watch Draco tonight as it circles around the North Star, Polaris.

Draco, with Ursa Minor or the Little Dipper, as depicted in Urania’s Mirror, a set of constellation cards published in London c. 1825.

Another noteworthy star in Draco is Thuban, which is high in the sky in the evening at this time of year. Thuban is an interesting star because – around 3000 B.C. – Thuban used to be the Pole Star.

The constellation Draco, by the way, has been associated with a dragon in many cultures. A Babylonian myth links Draco to the dragon god Tiamat, who was subdued by the god of the sun.

Bottom line: Here is Draco the Dragon on a July evening. Meet Rastaban and Eltanin – lovely, romantic names for Dragon stars! They represent the Eyes of the Dragon.

Read more: Eltanin and Rastaban, the Dragon’s Eyes

EarthSky’s meteor shower guide for 2019

Help support posts like these at the EarthSky store. Fun astronomy gifts and tools for all ages!

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Perseid meteor on the morning of August 12, 2017, from Hrvoje Crnjak in Šibenik, Croatia. Notice the variations in brightness and color throughout, and the little “pop” of brightness toward the bottom. A brightness “pop” like that comes from a clump of vaporizing debris. Thank you, Hrvoje! Click for more photos of 2017 Perseids.

The annual Perseid meteor shower is one of the most beloved meteor showers of the year, especially in the Northern Hemisphere, where the shower peaks on warm summer nights. No matter where you live worldwide, the 2019 Perseid meteor shower will probably produce the greatest number of meteors on the mornings of August 11, 12 and 13. Unfortunately, on the peak mornings in 2019, a bright moon will drown many Perseids from view. For those serious about seeing the greatest number of Perseids in 2019, we recommend viewing several mornings in a row, beginning the weekend of Friday, August 9 to Sunday, August 11. There will be considerably more moon-free viewing time then than at the Perseids’ likely peak from late evening August 12 until dawn August 13.

Visit the Sunrise Sunset Calendars site to find out when the moon sets in your sky, remembering to check the moonrise and moonset box.

But don’t wait. The 2019 Perseid meteor shower has already begun its slow and steady rise to its peak. And the new moon comes on July 31/August 1, meaning the morning hours in early August will be moon-free.

Camping in early August? Yes, please! The weekend of August 2 to 4 would be grand. Be on the lookout for Perseid meteors in the hours between midnight and dawn. Also remember, the the Delta Aquariid meteor shower will still be rambling along steadily. You’ll see mostly Perseids, but also some Delta Aquariids in the mix. There’s an explanation of how to tell the difference toward the bottom of this article.

The first full week of August (say, around August 5 to 8) will also offer moon-free skies – and hopefully some pleasant meteor-viewing – in those prime midnight-to-dawn hours.

In the Northern Hemisphere, we rank the August Perseids as an all-time favorite meteor shower of every year. For us, this major shower takes place during the lazy, hazy days of summer, when many families are on vacation. And what could be more luxurious than taking a siesta in the heat of the day and watching this summertime classic in the relative coolness of night?

People tend to focus on the peak mornings of the shower and that’s entirely appropriate. But meteors in annual showers – which come from streams of debris left behind in space by comets – typically last weeks, not days. Perseid meteors have been streaking across our skies since around July 17. We’ll see Perseids for 10 days or so after the peak mornings on August 11, 12 and 13. What’s more, the Perseids tend to build up gradually, yet fall off rapidly. So, any morning in late July through mid-August should offer a sprinkling of Perseid meteors.

Don’t rule out early evenings, either. In a typical year, although the meteor numbers increase after midnight, the Perseid meteors still start to fly at mid-to-late evening from northerly latitudes. South of the equator, the Perseids start to streak the sky around midnight. If fortune smiles upon you, the evening hours might offer you an earthgrazer – a looooong, slow, colorful meteor traveling horizontally across the evening sky. Earthgrazer meteors are rare but memorable. Perseid earthgrazers appear before midnight, when the radiant point of the shower is close to the horizon.

The radiant point for the Perseid meteor shower is in the constellation Perseus. But you don’t have to find a shower’s radiant point to see meteors. Instead, the meteors will be flying in all parts of the sky.

What is the radiant point for the Perseid meteor shower? If you trace all the Perseid meteors backward, they all seem to come from the constellation Perseus, near the famous Double Cluster. Hence, the meteor shower is named in the honor of the constellation Perseus the Hero.

However, this is a chance alignment of the meteor shower radiant with the constellation Perseus. The stars in Perseus are light-years distant while these meteors burn up about 60 miles (100 km) above the Earth’s surface. If any meteor survives its fiery plunge to hit the ground intact, the remaining portion is called a meteorite. Few – if any – meteors in meteor showers become meteorites, however, because of the flimsy nature of comet debris. Most meteorites are the remains of asteroids.

In ancient Greek star lore, Perseus is the son of the god Zeus and the mortal Danae. It is said that the Perseid shower commemorates the time when Zeus visited Danae, the mother of Perseus, in a shower of gold.

From mid-neorthern latitudes, the constellation Perseus, the stars Capella and Aldebaran, and the Pleiades cluster light up the northeast sky in the wee hours after midnight on August nights. The meteors radiate from Perseus.

Here’s a cool binocular object to look for while you’re watching the meteors. The constellation Cassiopeia points out the famous Double Cluster in northern tip of the constellation Perseus. Plus, the Double Cluster nearly marks the radiant of the Perseid meteor shower. Photo by Flickr user madmiked.

General rules for Perseid-watching. No special equipment, or knowledge of the constellations, needed.

Find a dark, open sky to enjoy the show. An open sky is essential because these meteors fly across the sky in many different directions and in front of numerous constellations.

Give yourself at least an hour of observing time, because the meteors in meteor showers come in spurts and are interspersed with lulls. Remember, your eyes can take as long as 20 minutes to adapt to the darkness of night. So don’t rush the process.

Know that the meteors all come from a single point in the sky. If you trace the paths of the Perseid meteors backwards, you’d find they all come from a point in front of the constellation Perseus. Don’t worry about which stars are Perseus. Just enjoying knowing and observing that they all come from one place on the sky’s dome.

Enjoy the comfort of a reclining lawn chair. Bring along some other things you might enjoy also, like a thermos filled with a hot drink.

Remember … all good things come to those who wait. Meteors are part of nature. There’s no way to predict exactly how many you’ll see on any given night. Find a good spot, watch, wait.

You’ll see some.

Composite of 12 images acquired on August 13, 2017, by Felix Zai in Toronto. He wrote: “Perseid meteor shower gave a good show even though the moonlight drowned out most of the fainter ones. A huge fireball was captured in this photo.” Thanks, Felix! By the way, it’s only in a meteor “storm” that you’d see this many meteors at once. Even in a rich shower, you typically see only 1 or 2 meteors at a time.

What’s the source of the Perseid meteor shower? Every year, from around July 17 to August 24, our planet Earth crosses the orbital path of Comet Swift-Tuttle, the parent of the Perseid meteor shower. Debris from this comet litters the comet’s orbit, but we don’t really get into the thick of the comet rubble until after the first week of August. The bits and pieces from Comet Swift-Tuttle slam into the Earth’s upper atmosphere at some 130,000 miles (210,000 km) per hour, lighting up the nighttime with fast-moving Perseid meteors.

If our planet happens to pass through an unusually dense clump of meteoroids – comet rubble – we’ll see an elevated number of meteors. We can always hope!

Comet Swift-Tuttle has a very eccentric – oblong – orbit that takes this comet outside the orbit of Pluto when farthest from the sun, and inside the Earth’s orbit when closest to the sun. It orbits the sun in a period of about 133 years. Every time this comet passes through the inner solar system, the sun warms and softens up the ices in the comet, causing it to release fresh comet material into its orbital stream.

Comet Swift-Tuttle last reached perihelion – closest point to the sun – in December 1992 and will do so next in July 2126.

Meteors in annual showers happen when Earth encounters debris left behind by a comet. Astronomers have learned to calculate the various streams of debris in space, left behind by comets as various passages near the sun. Image by AstroBob.

Russ Adams caught these 2 meteors, traveling on parallel paths, on the morning of August 11, 2017. Click for more 2017 Perseids.

Looking for a dark area to observe from? Check out EarthSky’s interactive, worldwide Best Places to Stargaze map.

Bottom line: The 2019 Perseid meteor shower is expected to produce the most meteors in the predawn hours of August 11, 12, and 13, though under the light of a bright waxing gibbous moon. But we recommend watching the Perseids on the weekend starting on Friday, August 9, as there will be more moon-free viewing time than on the expected peak date.

Everything you need to know: Delta Aquariid meteor shower

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EarthSky by Eleanor Imster - 23h ago

Joshua trees. Image © Doug/Adobe Stock.

A new study that looked at global warming’s impact on trees in California’s Joshua Tree National Park suggests that without dramatic action to reduce climate change, the iconic trees won’t survive much past this century.

The study, published June 3, 2019, in the peer-reviewed journal Ecosphere, examined data from more than 4,000 trees in order to predict how our warming climate might effect the park’s namesake trees, as well as to find out whether the trees are already in trouble.

The researchers found that Joshua trees have been migrating to higher elevation parts of the park that have cooler weather and more moisture in the ground. In hotter, drier areas, the adult trees aren’t producing as many younger plants, and the ones they do produce aren’t surviving.

Young Joshua trees like this one may be unable to survive under climate change. Image via Lynn Sweet/UCR.

Joshua trees as a species have existed since the Pleistocene era, about 2.5 million years ago, and individual trees can live up to 300 years. One of the ways adult trees survive so long is by storing large reserves of water to weather droughts. But younger trees and seedlings aren’t capable of holding reserves in this way, and the most recent, 376-week-long drought in California left the ground in some places without enough water to support new young plants. As the climate changes, long periods of drought are likely to occur with more frequency, leading to issues with the trees like those already observed, says the study.

An additional finding of the study is that in the cooler, wetter parts of the park the biggest threat, other than climate change, is fire. Fewer than 10 percent of Joshua trees survive wildfires, said the researchers.

The Milky Way arching over a Joshua tree, photographed by Manish Mamtani

According to the researchers, the new study suggests several possible outcomes. In the best-case scenario, major efforts to reduce heat-trapping gasses in the atmosphere would save 19 percent of the tree habitat after the year 2070. In the worst case, with no reduction in carbon emissions, the park would retain a mere 0.02 percent of its Joshua tree habitat.

Joshua Tree National Park. Image via California Travel and Tourism.

Bottom line: A new study predicts a gloomy future for the trees in California’s Joshua Tree National Park.

Source: Congruence between future distribution models and empirical data for an iconic species at Joshua Tree National Park

Via University of California, Riverside

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Meteors in annual showers happen when Earth encounters debris left behind by a comet. Astronomers have learned to calculate the various streams of debris in space, left behind by comets as various passages near the sun. Image by AstroBob.

Late July 2019 – around July 28 – presents the nominal peak of the Delta Aquariid meteor shower. But don’t let that date thwart you, if you have a chance to be in a dark place for meteor-watching, anytime in the coming weeks. The long and rambling Delta Aquariid shower is officially active from about July 12 to August 23 each year. The coming new moon on July 31/August 1 (depending on your time zone) means lovely waning crescents in the optimum predawn hours in late July. It means dark skies throughout most of the night all through the first week of August.

The Delta Aquariid shower favors the Southern Hemisphere, though is still visible from mid-northern latitudes. In years when the moon is out of the way, the broad maximum of this shower can be expected to produce 10 to 20 meteors per hour. But, even in early August, you’ll likely see some Perseids, too. This shower overlaps with the more famous Perseid meteor shower, which in early August is rising to its peak (this year on the mornings of August 11, 12 and 13, unfortunately under the light of a bright moon). Those who observe the Perseids are likely to see some Delta Aquariid meteors flying on the same nights.

For the Delta Aquariids, as for most meteor showers, the best viewing hours are after midnight and before dawn for all time zones around the world.

Everything you need to know: Perseid meteor shower

The radiant point for Delta Aquariid shower is near star Skat, or Delta Aquarii. This star is near in the sky to a much brighter star, Fomalhaut, which can be found roughly on a line drawn southward through the stars on the west side of the Great Square. This chart shows the Northern Hemisphere view. From the Southern Hemisphere, the radiant is closer to overhead. And don’t worry too much about radiant points. The meteors will appear in all parts of the sky.

How can I tell Perseid meteors from Delta Aquariid meteors? This is where the concept of a radiant point comes in handy. If you trace all the Delta Aquariid meteors backward, they appear to radiate from a certain point in front of the constellation Aquarius the Water Bearer, which, as viewed from the Northern Hemisphere, arcs across the southern sky. The radiant point of the shower nearly aligns with the star Skat (Delta Aquarii). The meteor shower is named in the honor of this star.

Meanwhile, the Perseids radiate from the constellation Perseus, in the northeast to high in the north between midnight and dawn. So – assuming you’re in the Northern Hemisphere – if you’re watching the Perseids, and you see meteors coming from the northeast or north … they are Perseids. If you see them coming from the south … they are Delta Aquariids. In a particularly rich year for meteors, if you have a dark sky, you might even see them cross paths! It can be an awesome display.

The Delta Aquariid meteors may tend to be a bit fainter than the Perseids and meteors seen in other major showers. That makes a dark sky free of moonlight even more imperative for watching the annual Delta Aquariid shower. About five to ten percent of the Delta Aquariid meteors leave persistent trains – glowing ionized gas trails that last a second or two after the meteor has passed. The meteors burn up in the upper atmosphere about 60 miles (100 km) above Earth’s surface.

Rememeber, you never have to locate a shower’s radiant point to enjoy the meteors. However, it does help to have a dark night without moonlight. This year – in 2019 – the prospects for watching the Delta Aquariids in late July and early August are very good, with little moonlight to ruin the show.

Comet 96P Machholz, the possible parent of the Delta Aquariid meteor shower, was discovered on May 12, 1986, by Donald Machholz. Image via Wikimedia Commons[./caption]

Delta Aquariid meteors may come from Comet 96P Machholz. Meteor showers happen when our planet Earth crosses the orbital path of a comet. When a comet nears the sun and warms up, it sheds bits and pieces that spread out into that comet’s orbital stream. This comet debris slams into the Earth’s upper atmosphere at about 90,000 miles (150,000 km) per hour, vaporizing – burning up – as meteors or shooting stars.

The parent body of the Delta Aquariid meteor is not known with certainty. It was once thought to have originated from the breakup of what are now the Marsden and Kracht sungrazing comets. More recently, the Comet 96P Machholz has loomed as the primary candidate for being the Delta Aquariids’ parent body.

Donald Machholz discovered this comet in 1986. It’s a short-period comet whose orbit carries it around the sun once in a little over five years. At aphelion – its greatest distance from the sun – this comet goes out beyond the orbit of Jupiter. At perihelion – its closest point to the sun – Comet 96P Machholz swings well inside Mercury’s orbit. Comet 96P/Machholz last came to perihelion on October 27, 2017 and will next come to perihelion on January 31, 2023.

[caption id="attachment_203199" width="800"] David S. Brown caught this meteor in late July in 2014, in southwest Wyoming.

Kelly Dreller caught this meteor in late July of 2016, in Lake Havasu City, Arizona.

Bottom line: The Delta Aquariid meteor shower lacks a very definite peak. It rambles along pretty steadily in late July and August, coinciding with the Perseids. The nominal peak is in late July, shortly before the new moon on August 1, 2019. From any time zone, the best viewing window lasts for several hours, centered on roughly 2 a.m. (3 a.m. daylight saving time). Find an open sky away from artificial lights, lie down on a reclining lawn chair and look upward.

Everything you need to know: Perseid meteor shower

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Tonight, look for the faint constellation Ophiuchus the Serpent Bearer. From the Northern Hemisphere, look southward at nightfall. From the Southern Hemisphere, look more overhead around mid-evening. From all parts of Earth, Ophiuchus crosses the sky westward as Earth spins under the sky, and as evening deepens into late night. Ophiuchus is sometimes called the 13th or forgotten constellation of the zodiac.

The sun passes in front of Ophiuchus from about November 30 to December 18. And yet no one ever says they’re born when the sun is in Ophiuchus. That’s because Ophiuchus is a constellation – not a sign – of the zodiac.

Ophiuchus in Urania’s Mirror, a boxed set of 32 constellation cards first published in 1824. Image via www.ianridpath.com.

What’s the difference? The 12 signs of the tropical zodiac represent equal 30 degree divisions of the sky, while the 13 constellations of the zodiac are of various sizes.

That’s why, for example, the sun resides in front of each zodiacal sign for a precise interval of about a month. Meanwhile, the sun is in front of the constellations for varying amounts of time, for example, in front of the constellation Virgo for about 1 1/2 months and in front of constellation Scorpius for about a week.

The planet Jupiter and the bright red star Antares in the constellation Scorpius the Scorpion can help you find Ophiuchus in the night sky. Jupiter actually shines in front of Ophiuchus in 2019. Meanwhile, Ophiuchus is to the north of the star Antares.

Even after Jupiter moves into different constellations of the zodiac in the years ahead, you can look for Ophiuchus a short hop to the north of Antares in any year. Ophiuchus’ brightest star – the 2nd-magnitude star called Rasalhague – highlights the head of Ophiuchus. (See Rasalhague in the Ophiuchus chart below.) It’s nowhere as bright as the planet Jupiter or the 1st-magnitude star Antares.

Help support posts like these at the EarthSky store. Fun astronomy gifts and tools for all ages.

Ophiuchus the Serpent Bearer, via Wikimedia Commons.

On sky maps, Ophiuchus the Serpent Bearer is depicted as holding Serpens the Serpent, which is considered a separate constellation. According to ancient Greek star lore, Ophiuchus is Asclepius, the physician who concocted a healing potion from the Serpent’s venom, mixing it with the Gorgon’s blood and an unknown herb. This potion gave humans access to immortality, until the god of the underworld appealed to Zeus to reconsider the ramifications of the death of death.

Even today, the Staff of Asclepius – the symbol of the World Heath Organization – pays tribute to the constellation Ophiuchus the Serpent Bearer.

Bottom line: Will you see faint Ophiuchus, the overlooked zodiacal constellation, tonight?

Read more: Born between November 29 and December 18? Here’s your constellation

Dates of sun’s entry into each constellation of the zodiac

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EarthSky by Sharmila Kuthunur - 2d ago

The climbing robot LEMUR rests after scaling a cliff in Death Valley, California in early 2019. The robot uses special gripping technology that has helped lead to a series of new, off-roading robots that can explore other worlds. Image via NASA/JPL-Caltech.

From uncovering the first clues of liquid water on Mars to crossing our solar system, NASA’s missions have been adventurous, to say the least. Ranger 3 was NASA’s first attempt to land a rover on the moon in 1962. Since then, numerous robots have followed Ranger 3 from Earth into space. Yet the surfaces of planets and moons in our solar system remain largely unexplored, partly because current space robots haven’t been capable of scaling cliffs, gripping icy surfaces and otherwise conquering hard-to-reach places.

This month (July 10, 2019), NASA’s Jet Propulsion Laboratory described its work on a new family of robots that can roll, climb, and use artificial intelligence (AI) to navigate around obstacles in rough terrains. These robots are currently being tested on Earth and will later be sent to places that are otherwise inaccessible by humans, helping scientists do meaningful science along the way.

A tiny climbing robot rolls up a wall, gripping with fishhooks – technology adapted from LEMUR’s gripping feet. Image via NASA/JPL-Caltech.

This new class of space robots will have functionalities inspired by the Limbed Excursion Mechanical Utility Robot (LEMUR), which was originally conceived as a repair robot for the International Space Station. In the video below, NASA describes LEMUR’s last field test, in Death Valley, California, in early 2019. The robot used hundreds of fishhooks to climb walls and AI to avoid obstacles that it could not climb. It also used its suite of scientific instruments to scan the rock for ancient fossils, and, as the video explains, it found some!

NASA Climbing Robot Scales Cliffs and Looks for Life - YouTube

A direct application of this LEMUR field test would be searching for biosignatures – substances that provide evidence of life – on the planet Mars, perhaps in lake beds thought to hold signs of Martian life from the distant past.

While the LEMUR itself will not be sent into space, the engineers did adopt much of its AI and structural features into the next generation of robots that will act as our eyes and ears beyond Earth. Each one of them has unique features built into it to tackle harsh conditions and uncertain environments. Keep reading, to meet this new generation of space explorers.

Ice Worm was put to its first field test in the cave walls at Mount St. Helens in August 2018. The robot was belayed with a rope to ensure that it wasn’t damaged if it fell. Image via NASA/JPL-Caltech.

Ice Worm

Engineers at NASA’s Jet Propulsion Laboratory in Pasadena, California, are developing a robot called Ice Worm in an attempt to navigate slippery surfaces. True to its name, the robot – adapted from a single limb of LEMUR – compacts its body before extending it to move forward. It proceeds an inch at a time by drilling one end of a limb into an icy surface, uses a grip to steady itself, then brings in the second limb to join the first using the same technique.

To move forward, it unscrews one foot, lengthens its body and screws it back into the ice a few meters ahead. Using the pressure sensors that instruct it how hard to drill into the ice, it repeats this over and over again to “inchworm” forward. Ice Worm also uses this method to anchor itself while analyzing the surface beneath to collect material in its legs that can be used to test salinity concentrations for microbial life.

Aaron Parness, an engineer at JPL, has trained Ice Worm in the remote regions of Antarctica, which is the harshest place they could find on Earth. The slippery ice coupled with the harsh environment will prepare the robot for similar conditions on the moons of Jupiter and Saturn. Another set of tests are lined up in glaciers on Mt. Rainier in Seattle. Parness commented:

Field testing shows you things that are hard to learn in the laboratory.

This 1.4-meter (4.6 foot) long robot is also being equipped with pattern recognition and machine learning – aspects of AI that allow it to learn from past mistakes and make optimal decisions. The robot will need to investigate patterns left behind by life in cave formations. In order to do so, it needs to be tiny and mobile enough to scuttle through the cave’s tiny gaps. For this, Parness and his team are working on miniaturized remote sensing and data analysis instruments that Ice Worm can wear like a backpack. Once ready, robots of this kind will be sent to the icy moons of Saturn and Jupiter to bring back samples for further analyses.

Read more about Ice Worm

RoboSimian during a field test in California. Image via NASA/JPL-Caltech.

RoboSimian

While this four-legged robot is also inspired by LEMUR in its size and build, RoboSimian has supple wheels made of music wire in contrast to LEMUR’s gripping ones, thus having greater flexibility on rough terrains. This concept first materialized as a part of the DARPA Robotics Challenge, which promoted robotic technology for disaster-response operations. The robot is built and trained to operate in dangerous environments, so it’s not surprising that RoboSimian – a four-legged robot that can walk, crawl, slide on its belly, and even do cartwheels – will most likely be sent to Saturn’s moon Enceladus. Saltwater oceans are theorized to be present under the icy surface of that distant moon. Its geysers may also contain signs of microbial life.

Nicknamed King Louie after a character in the film “Jungle Book,” RoboSimian is equipped with spectroscopic instruments that could explore Enceladus’ polar regions.

Read more about RoboSimian

NASA engineers were inspired by gecko feet, such as the one shown here, in designing a gripping system for space. Just as a gecko’s foot has tiny adhesive hairs, so the JPL devices incorporate small structures that work in similar ways. Image via NASA/Wikimedia Commons.

Building robots the gecko way

You can use tape only so many times before the adhesion wears off. Geckos, on the other hand, offer inspiration for glues that stick even after multiple uses. These tiny lizards have hair on their feet that allow them to cling to a wall with ease. Parness and his team designed a robot with similar features – gecko-inspired adhesives – synthetic hair that sticks to any surface.

These grippers can sustain up to 150 Newtons of force and have been tested in simulated microgravity environments. The gecko material itself was tested 300,000 times to make sure the stickiness does not wear off. This robot will one day repair satellites, service them, and even snatch space garbage.

Read more about gecko-inspired robot grippers

Underwater Gripper at work. Image via Nautilus.

Underwater grippers

Yet another robot inspired by LEMUR, the Underwater Gripper, adopted LEMUR’s 16 fingers and 250 fishhooks to hold on tightly to surfaces and drill into formations. This is particularly useful in environments where there is little to no gravity, especially underwater where the force of the drill could push the robot away.

As of now the robot is working with Nautilus – an underwater research vessel – to collect samples from water that are a mile below the surface. Eventually, it might be sent to explore the surfaces of asteroids and other similar bodies.

Read more about underwater robot grippers

NASA’s Mars Helicopter in NASA’s Jet Propulsion Laboratory in Pasadena, California. Image via NASA/JPL.

A helicopter that will do more than just fly

A tiny, solar-powered helicopter will accompany the Mars 2020 rover. Arash Kalantari, a JPL engineer, modified LEMUR’s design to build a robot that lands not just horizontally, but also vertically by clinging to rocks like a dragonfly.

MiMi Aung, project manager for the Mars Helicopter at NASA’s Jet Propulsion Laboratory in Pasadena, California, said:

Nobody’s built a Mars Helicopter before, so we are continuously entering new territory.

The Mars Helicopter is expected to reach Mars by February 2021 and will conduct geological assessments on the landing sites, assess natural resources and hazards for future space missions.

Read more about the Mars Helicopter

Bottom line: A new class of space robots have functionalities inspired by the Limbed Excursion Mechanical Utility Robot (LEMUR). While each design is unique in its abilities, there is one common goal that unites them all: the hunt for life beyond Earth.

Via NASA

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Map showing the location of Earth’s tropics and subtropics. Scientists have noted increased coral growth in the subtropics, the area between tropical and temperate latitudes, as climate warms. Map via Wikimedia Commons.

Scientists have detected increases in coral populations in subtropical waters, which could help to offset some of the coral declines in warming waters around the equator. The new research was published in the peer-reviewed journal Marine Ecology Progress Series on July 4, 2019.

Warming waters around the equator are inducing coral bleaching events and die-offs. Unlike fish and crustaceans, which are mobile and able to relocate to cooler waters when living conditions deteriorate, adult corals are sessile organisms for which migration is not possible. Hence, they are particularly susceptible to heat stress induced by El Niño events and climate change.

Coral larvae, however, are mobile. After new larvae are produced through fertilization, they swim around in the ocean for days to weeks searching for a nice hard spot to land. Once settled, the larvae metamorphosize into sessile polyps and form new coral colonies and reefs. Scientists routinely assess the recruitment of new coral larvae by placing artificial tiles around the ocean bottom and counting the number of polyps that develop over time.

Coral growth in the temperate waters around Nagasaki, Japan. Image via Soyoka Muko, Nagasaki University.

In this new research, scientists first compiled a long-term coral recruitment database from past studies conducted from 1974 to 2012. Then, they examined the trends in recruitment over time. The findings showed that new coral recruitment has declined by 85 percent in tropical waters (less than 20 degrees latitude), but surprisingly, a 78 percent increase in recruitment was observed in cooler, subtropical waters (greater than 20 degrees latitude). Places with increases in recruitment include Shikoku, Japan, and the Flower Garden Banks in the northern Gulf of Mexico. The increases in recruitment were observed on both sides of the equator, thus indicating that this is a global trend and not just a site specific one.

Nichole Price, lead author of the study and senior research scientist at the Bigelow Laboratory for Ocean Sciences, commented on the findings in a press release. She said:

Climate change seems to be redistributing coral reefs, the same way it is shifting many other marine species. The clarity in this trend is stunning, but we don’t yet know whether the new reefs can support the incredible diversity of tropical systems.

The scientists think that the best places for new coral recruitment in a future, warmer world may be in narrow zones just above tropical waters. At more northerly or southerly latitudes, coral growth would likely be limited by the low winter light intensity among other factors. Hence, despite the good news, coral conservation in tropical waters remains a critical issue.

Coral recruitment tiles installed at the Palmyra Atoll National Wildlife Refuge for the study of new coral growth in the region. Image via Nichole Price, Bigelow Laboratory for Ocean Sciences.

Price also emphasized that more follow-up research is necessary:

So many questions remain about which species are and are not making it to these new locations, and we don’t yet know the fate of these young corals over longer time frames. The changes we are seeing in coral reef ecosystems are mind-boggling, and we need to work hard to document how these systems work and learn what we can do to save them before it’s too late.

The new research was published by an international team of 19 scientists, with funding support from the U.S. National Science Foundation and the Okinawa Institute of Science and Technology.

View larger. | Coral recruitment study sites (n = 185). Shaded shapes of various colors (see key) indicate Marine Ecosystems of the World (MEOW) marine provinces. Within the colored shaded shapes, red dots identify the 12 locations – where long-immersion tiles were deployed over at least 4 years – used for analyses of changes in recruitment over time; black dots identify all other study sites. Map via Price et al.

Bottom line: New long-term data show that coral populations have declined by 85 percent in tropical waters over the past few decades, but risen by 78 percent in a narrow zone of cooler subtropical waters.

Source: Global biogeography of coral recruitment: tropical decline and subtropical increase

Via EurekAlert

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The Summer Triangle is not a constellation but a large asterism consisting of three bright stars in three separate constellations. These stars are Vega, Deneb and Altair. If you can find the Summer Triangle, you can use it to locate three of the sky’s smallest constellations: Vulpecula the Fox, Delphinus the Dolphin and Sagitta the Arrow. All three would be impossible to see from the city, but they’re lots of fun to see in a dark sky.

How can you find them? Look at the detailed chart below, and try picking out Vega, Deneb and Altair. Notice the large triangle they make if you draw lines between them. This triangle pattern – which is easily found in the sky on Northern Hemisphere summer evenings – is the Summer Triangle.

Now – still using the chart at the bottom of this post – or maybe after purchasing this awesome constellation chart from the store at Skyandtelescope.org – look within and around the Summer Triangle for Delphinus, Sagitta and Vulpecula.

Delphinus is a truly delightful little constellation that really resembles a dolphin leaping among the waves. Delphinus is one of the earliest constellations, first catalogued by the Greek astronomer Ptolemy in the 2nd century. Sometimes, Delphinus is said to be the Dolphin that carried a Greek poet – Arion – safely away from his enemies. Other times, this sky Dolphin is said to represent the dolphin sent by the sea god Poseidon to find Amphitrite, the Nereid he wanted to marry.

Sagitta – the 3rd smallest constellation in our sky – is near Vulpecula on the sky’s dome. Its name means “the arrow” in Latin. If you look for Sagitta, you’ll see why. This little star pattern does have a shape reminiscent of an arrow. Sagitta is also one of the earlist constellations, named by Ptolemy in the 2nd century. Sagitta is sometimes said to be an arrow shot from the bow of Hercules, a mythological hero and god.

Vulpecula means “the little fox” in Latin, and it’s the hardest to find of these three small constellations because it lacks a distinctive shape. Vulpecula is a relatively new constellation, introduced by the Polish astronomer Johannes Hevelius in the late 17th century. If you’re up for a binocular challenge, also try finding the Coathanger asterism in Vulpecula.

View larger. | Once you’re familiar with the Summer Triangle, star-hop from there to the nearby small constellations. Chart via IAU and Sky & Telescope (Roger Sinnott & Rick Fienberg)/Wikimedia Commons.

Want more about the Summer Triangle? Check out these articles.

Part 1: Vega and its constellation Lyra

Part 2: Deneb and its constellation Cygnus

Part 3: Altair and its constellation Aquila

Bottom line: You need a dark country sky to see these 3 small constellations: Vulpecula the Fox, Delphinus the Dolphin and Sagitta the Arrow.

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