When the sun dies

What does death mean for the sun? It means our sun will run out of fuel in its interior. It’ll cease the internal thermonuclear reactions that enable stars to shine. It’ll swell into a red giant, whose outer layers will engulf Mercury and Venus and likely reach the Earth. Life on Earth will end.

If the sun were more massive – estimates vary, but at least several times more massive – it would explode as a supernova. So … no supernova. But what? What happens next? An international team of astronomers used a stellar data-model that predicts the life cycle of stars to answer this question.

Their research was published in the peer-reviewed journal Nature Astronomy and is available to read at arXiv.org. It suggested that the sun is almost exactly the lowest mass star that – at the end of its life – produces a visible, though faint, planetary nebula.

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About planetary nebulae

The name planetary nebula has nothing to do with planets. It describes a massive sphere of luminous gas and dust, material sloughed off an aging star. In the 1780s, William Herschel called these spherical clouds planetary nebulae because, through his early telescope, planetary nebulae looked round, like the planets in our solar system.

Astronomers already knew that 90% of all stars end their active lives as planetary nebulae. They were reasonably sure our sun would meet this fate. The key word here is visible. For years, scientists thought the sun has too low mass to create a visible planetary nebula.

Albert Zijlstra of the University of Manchester in England is a co-author of the study. He said in a statement:

When a star dies it ejects a mass of gas and dust – known as its envelope – into space. The envelope can be as much as half the star’s mass. This reveals the star’s core, which by this point in the star’s life is running out of fuel, eventually turning off and before finally dying.

It is only then the hot core makes the ejected envelope shine brightly for around 10,000 years – a brief period in astronomy. This is what makes the planetary nebula visible. Some are so bright that they can be seen from extremely large distances measuring tens of millions of light-years, where the star itself would have been much too faint to see.

The fate of our sun

Will that be the fate of our sun? Will it – at the end of its life – become briefly visible to alien astronomers on planets millions of light-years away? These astronomers say no. They say their models predict that our sun – though forming a planetary nebula at the end of its life – will remain faint.

Read more about this study from the University of Manchester

By the way … what happens next? Eventually, the planetary nebula will disperse and fade. With its thermonuclear fuel gone, the sun will no longer be able to shine. The immensely high pressures and temperatures in its interior will slacken. The sun will shrink down to become a dying ember of a star, known as a white dwarf, only a little larger than Earth.

Bottom line: A study suggests our sun is about the lowest mass star that – at the end of its life – produces a visible, though faint, planetary nebula. What that is … and more on the fate of our sun, here.

Source: The mysterious cut-off of the Planetary Nebula Luminosity Function

Via University of Manchester

The post When our sun dies, what will happen to Earth? first appeared on EarthSky.

What are crepuscular rays?

Crepuscular means like twilight or dim. This phenomenon occurs around sunrise or sunset, when the sky is somewhat dark. Crepuscular rays may appear to fan across the sky, but the rays are really parallel to each other. The sunbeams appear to diverge, much as a road that looks narrow in the distance appears wide beneath your feet. Airborne dust, droplets of water and the air molecules themselves are what make the sunrays visible. Next time you see them, remember to turn around. You might be in luck and see fainter and less noticeable anticrepuscular rays.

Crepuscular rays can also go by the name of sunray. Some people also apply the term crepuscular ray for sunbeams that radiate from the direction of the sun while it is still above the horizon but hidden behind clouds. Although technically, a crepuscular ray requires the sun to be below the horizon. The photos of sunbeams coming from a sun still above the horizon also have the nickname Jacob’s Ladder. The term comes from a story in the bible where Jacob has a dream in which he sees a ladder leading up to the golden light of heaven with angels ascending and descending.

All of these photos were contributed by EarthSky friends. Thanks for sharing your awesome photos with us!

Photo gallery of crepuscular rays

Moon rays or Moonbeams

Bottom line: Crepuscular rays form when the sun is below the horizon but light beams streak into the darkening sky. Anticrepuscular rays are on the horizon opposite the sun.

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The post Crepuscular rays: Photos from our readers first appeared on EarthSky.

Comets and asteroids usually differ in composition

Comets and asteroids are both members of our solar system. Both were born from the same great primordial cloud of dust and gas that created Earth and the other planets, 4.5 billion years ago. But comets and asteroids have differences. They can usually (but not always) be distinguished by what they’re made of, and by where they’re found in the solar system. Both are small bodies orbiting the sun. But it’s usually easy to tell them apart.

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Asteroids

Asteroids mostly reside in the asteroid belt, a wheel-shaped region of our solar system between the fourth planet, Mars, and the fifth planet, Jupiter. NASA explains:

The majority of known asteroids orbit within the asteroid belt between Mars and Jupiter, generally with not very elongated orbits. The belt is estimated to contain between 1.1 and 1.9 million asteroids larger than 1 kilometer (0.6 mile) in diameter, and millions of smaller ones. Early in the history of the solar system, the gravity of newly formed Jupiter brought an end to the formation of planetary bodies in this region and caused the small bodies to collide with one another, fragmenting them into the asteroids we observe today.

So asteroids are little bodies that might have gone into making another planet, but didn’t. Their compositions are reminiscent of the composition of Earth itself; they’re made of metals and rocky materials.

Also, asteroids have lumpy potato-like shapes.

How are asteroids named?

The International Astronomical Union has the responsibility for assigning asteroid names. The first asteroids discovered were given names from ancient mythology, while newer names can honor anything from people (such as 3505 Byrd) to bands (8749 Beatles).

Comets

In contrast to asteroids, most comets come from beyond the orbit of Pluto, in a region of the solar system called the Oort Cloud. Comets tend to have much more elongated orbits than asteroids, sometimes reaching so far out into the outer reaches of our solar system that passing stars can perturb these small bodies. When that happens, a comet may plunge inward toward our sun. Comets are icier than asteroids because they formed in the deep freeze of the outer solar system. They’re composed of rock and ice, earning them the nickname dirty snowballs.

It’s when comets sweep in close to the sun that they produce their characteristic gas and dust tails.

Comets are named for their discoverers.  

Read more: What are comets?

Of course, there are oddities with both comets and asteroids

Not all comets and asteroids fall into the neat categories mentioned above. Besides comets that come from the Oort Cloud, another group of comets orbit much closer to the sun. They are short-period comets and have orbital periods less than 200 years. Most short-period comets move in orbits that are the same direction as the planets. One notable exception to this is the most famous comet of them all, Halley’s Comet.

Both comets and asteroids are parent objects to meteor showers

Here’s another strange twist on the distinctions that exist between comets and asteroids. That is, comets are the usual parent objects for our annual meteor showers. Comets are flimsy objects, and, when they come close to the sun, they often leave behind a trail of icy debris. Every year, Earth plows through many old comet paths. This cometary debris enters our atmosphere, and that’s why we experience meteor showers.

For example, the Orionids and Eta Aquariids are both showers made from debris left behind by Halley’s Comet. Comet Tempel-Tuttle is the source of the Leonid meteor shower. But not all meteor showers stem from comets. The Geminid meteor shower – seen every December – has a mysterious object called 3200 Phaethon as its source. This object is sometimes called a rock-comet; that’s because in many ways, it’s like an asteroid-comet hybrid.

3200 Phaethon, the weird asteroid with a tail, isn’t the only object blurring the border between asteroids and comets. The Hubble Space Telescope captured an image of asteroid 311P/PANSTARRS and revealed it has six tails! So this strange asteroid is also a main-belt comet, and as a bonus it may have a satellite in orbit around it.

Bottom line: Most asteroids are rocky bodies that lie within the asteroid belt while comets are dirty snowballs from the Oort Cloud, with some objects acting like a hybrid of these two types.

The post Comets and asteroids: What’s the difference? first appeared on EarthSky.

1st photo of Earth from space

Were you alive before we saw Earth from space? If so, you were born on or before October 24, 1946. That was when a group of soldiers and scientists in the New Mexico desert launched a V-2 rocket – carrying a 35-mm motion picture camera – to a height 65 miles (105 km) above Earth’s surface. NASA defines the edge of space as 50 miles (80 km) above the surface. After a few minutes, the camera dropped back to Earth and was destroyed on impact. But the film survived.

Reliving the momentous day

Air & Space magazine tells the story of this major event in space history:

Snapping a new frame every second and a half, the rocket-borne camera climbed straight up, then fell back to Earth minutes later, slamming into the ground at 500 feet per second. The camera itself was smashed, but the film, protected in a steel cassette, was unharmed.

Fred Rulli was a 19-year-old enlisted man assigned to the recovery team that drove into the desert to retrieve film from those early V-2 shots. When the scientists found the cassette in good shape, he recalls, “They were ecstatic, they were jumping up and down like kids.” Later, back at the launch site, “when they first projected [the photos] onto the screen, the scientists just went nuts.”

Before 1946, the highest pictures ever taken of the Earth’s surface were from the Explorer II balloon, which had ascended 13.7 miles in 1935, high enough to discern the curvature of the Earth. The V-2 cameras reached more than five times that altitude, where they clearly showed the planet set against the blackness of space. When the movie frames were stitched together, Clyde Holliday, the engineer who developed the camera, wrote in National Geographic in 1950, the V-2 photos showed for the first time “how our Earth would look to visitors from another planet coming in on a space ship.”

Another early image from space

See a panorama of Earth from 1948 here

See videos and read the rest of the story from Air & Space.

Bottom line: On October 24, 1946, a movie camera on board a V-2 rocket captured the first photo of Earth from outer space.

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The post 1st photo of Earth from space, 76 years ago first appeared on EarthSky.

51 Pegasi b: 1st planet found orbiting a sunlike star

October 6, 1995: On this date, astronomers Michel Mayor and Didier Queloz announced the discovery of the first planet in orbit around a distant sunlike star. They later published their finding in the journal Nature, in a paper titled simply A Jupiter-Mass Companion to a Solar-type Star.

The star was 51 Pegasi, located about 50 light-years away in the constellation Pegasus the Flying Horse. Astronomers officially designated the new planet as 51 Pegasi b, in accordance with nomenclature already decided upon for extrasolar planets. The b means that this planet was the first discovered orbiting its parent star. If additional planets are ever found for the star 51 Pegasi, they’ll be designated c, d, e, f, and so on. So far, this planet is the only one known in this system.

Other names for the planet 51 Pegasi b

Astronomers call 51 Pegasi b by other names. The astronomer Geoffrey Marcy dubbed it Bellerophon. Marcy helped confirm its existence and was following the convention of naming planets after Greek and Roman mythological figures. In fact, Bellerophon was a figure from Greek mythology who rode the winged horse Pegasus. Later, in the course of its NameExoWorlds contest, the International Astronomical Union named this planet Dimidium. Which is Latin for half, referring to its mass of at least half the mass of Jupiter.

Also, astronomers consider 51 Pegasi b the prototype for the class of planets astronomers call hot Jupiters.

51 Pegasi b was the first of thousands of exoplanets

While 51 Pegasi b was the first, we now know there are thousands of exoplanets. As of September 2022, astronomers have confirmed more than 5,100 exoplanets.

But 51 Pegasi b will always be the first known exoplanet to orbit a star like our sun.

What we know about 51 Pegasi b

What do we know today of 51 Pegasi b, a world whose place in astronomical history is so secure? Its mass is about half that of Jupiter. It’s thought to have a larger diameter than Jupiter (the biggest planet in our solar system), despite its smaller mass. 51 Pegasi b orbits very close to its parent star, requiring only four days to orbit its star. As you know, the Earth orbits the sun in 365 days. It takes Jupiter 12 years to complete one orbit. In other words, 51 Pegasi b orbits very close to its star.

It’s also known that this planet is tidally locked to its star, much as our moon is tidally locked to Earth. So, the planet is always presenting the same face to Pegasi 51. Plus, it’s what’s known today as a hot Jupiter.

By the way, detailed pictures you see of exoplanets, such as the one at the top of this post, are always artists’ concepts. Even the largest earthly telescopes can’t see planets orbiting distant suns in anything like this amount of detail. At best, through earthly telescopes, they look like dots. Still, analyzing exoplanets – their atmospheres, for example, and their potential for life – is a major priority for NASA and for many astronomers in the years ahead. In fact, the Webb telescope has already imaged an exoplanet.

Searching for exoplanets is challenging

Consider that, before 51 Pegasi b, the search for exoplanets – worlds beyond our own solar system – was exceedingly difficult. Once astronomers began in earnest to search for them, they searched for decades before finding any. In nearly all cases, the light of their parent stars hides any exoplanets orbiting them. So, astronomers had to develop clever technologies to discover them. As with many extrasolar planets, astronomers used the radial velocity method to locate Pegasi 51 b. Click here to learn more about how astronomers find exoplanets.

Bottom line: On October 6, 1995, astronomers Michel Mayor and Didier Queloz announced the discovery of the first planet orbiting around a distant sunlike star. This planet is 51 Pegasi b.

The post 1st planet orbiting a sunlike star discovered 27 years ago first appeared on EarthSky.

Sputnik surprised the world 65 years ago

October 4, 1957. On this date, the Soviet Union launched Sputnik I, the first artificial satellite to orbit the Earth. Consequently, many space historians say the Space Age began on this date.

Basically, Sputnik was a polished metal sphere made of aluminum alloy. Specifically, it was 23 inches (58 cm) in diameter – about the size of a beach ball – and weighed just 184 pounds (83 kilograms). Also it had four external radio antennae to broadcast radio pulses. And broadcast they did. Indeed, people around the globe heard Sputnik’s unassuming beep beep on the radio for 21 days in 1957.

By the way, do you want to hear it? Check out the video below.

Sputnik had several primary objectives

Furthermore, the pressurized sphere had five primary science objectives: test a process for placing an artificial “moon” into Earth orbit; provide information on the density of Earth’s atmosphere, calculated from Sputnik’s lifetime in orbit; test radio and optical methods of orbital tracking; determine the effects of radio wave propagation though Earth’s atmosphere; and check principles of pressurization used on Earth-orbiting satellites.

While Sputnik’s beeping was a remarkable accomplishment for the Soviet Union, it also led to what many assumed was Russia’s superiority in space. To this end, the world feared the Soviets’ now had the ability to launch satellites. More specifically, concern Russia could launch ballistic missiles carrying nuclear weapons to Europe and the U.S.

Next launch: The first living creature in space

After that, the next step was to place a living creature in space. So on November 3, 1957, the Soviets launched Sputnik II, this time carrying a much heavier payload, including a stray dog named Laika. As a matter of fact, they found Laika on the streets of Moscow just over a week before Sputnik II was set to launch. But, according to the BBC, Laika died within hours of launch from panic and overheating. Read more about Laika from Time.com.

As a result: The beginning of the space race

Naturally, Sputnik I and Sputnik II sent shockwaves around the world. And American political leadership scrambled to catch up. In the long run, that extra push resulted in the United States sending the first astronauts to walk on the moon, on July 20, 1969.

For a musical take on the sudden advent of the Space Age, by Leslie Fish.

Bottom line: On October 4, 1957, 65 years ago, the Soviet Union launched the Sputnik I satellite into Earth orbit, and the Space Age began.

The post Sputnik launched 65 years ago first appeared on EarthSky.

What causes an aurora?

Auroras appear near both the north and south poles as the aurora borealis and the aurora australis. You may have noticed more aurora alerts lately as the sun has become more active. In fact, the bright blasts of activity on the sun are directly linked to these wispy, elusive lights we see in the night sky.

Storms on the sun that cause events such as coronal mass ejections and solar wind from coronal holes send charged particles hurtling across space. Because our sun is 93 million miles away (150 million km), the eruption we witness on the sun can take several days to reach our atmosphere. But if Earth is in the path of the particle stream, our planet’s magnetic field and atmosphere react from the impact.

When the charged particles from the sun strike atoms and molecules in Earth’s atmosphere, they excite those atoms, causing them to light up.

When charged particles interact with Earth’s atmosphere

What does it mean for an atom to be excited? Atoms consist of a central nucleus and a surrounding cloud of electrons encircling the nucleus in an orbit. When charged particles from the sun strike atoms in Earth’s atmosphere, electrons move to higher-energy orbits, further away from the nucleus. Then when an electron moves back to a lower-energy orbit, it releases a particle of light or photon.

What happens in an aurora is similar to what happens in the neon lights we see on many business signs. Electricity excites the atoms in the neon gas within the glass tubes of a neon sign. That’s why these signs give off their brilliant colors. The aurora works on the same principle, but at a far vaster scale.

The shapes of the northern and southern lights

The aurora often appears as curtains of lights, but they can also be arcs or spirals, following lines of force in Earth’s magnetic field. Most are green in color, but sometimes you’ll see a hint of pink. Strong displays might also have red, violet and white colors. The lights typically appear in the far north – the nations bordering the Arctic Ocean – Canada, Scandinavian countries, Iceland, Russia and the state of Alaska. But strong displays can extend down into more southerly latitudes. And of course, the lights have a counterpart at Earth’s south polar regions, though there is less land at high southerly latitudes for people to witness the displays.

The colors in the aurora were once a source of mystery throughout human history. But science says that different gases in Earth’s atmosphere give off different colors when they are excited. Oxygen gives off the green color of the aurora, for example. Nitrogen causes blue or red colors.

So today the mystery of the aurora is not so mysterious as it used to be. Yet people still travel thousands of miles to see the brilliant natural light shows in Earth’s atmosphere. And even though we know the scientific reason for the aurora, the dazzling natural light show can still fire our imaginations to visualize fire bridges, gods or dancing ghosts.

Ancient explanations and mythology behind the aurora

People have seen these dancing lights for millennia and have had their own explanations for them. Those who live at or visit high latitudes are sometimes lucky enough to experience these colored lights shimmering across the night sky. Some Inuit believed that they were seeing the spirits of their ancestors dancing in the flickering aurora. In Norse mythology, the aurora was a fire bridge to the sky that the gods built. You can read more about the mythology of the aurora here.

Mike Taylor’s photos of the aurora

EarthSky friend Mike Taylor shared these incredible aurora images with us.

Bottom line: When charged particles from the sun strike atoms in Earth’s atmosphere, they cause electrons in the atoms to move to a higher-energy state. When the electrons drop back to a lower energy state, they release a photon: light. This process creates the beautiful aurora, or northern and southern lights.

The post What causes an aurora, the northern or southern lights? first appeared on EarthSky.

CME strikes Solar Orbiter

Venus is on the far side of the sun from Earth now, about to pass out of our view. And the sun is in an upswing of its 11-year cycle. So it’s blasting out CMEs, aka coronal mass ejections, pretty frequently now, in all directions. Solar Orbiter launched from Earth in February of 2020. And it’s now in an elliptical orbit around the sun. It’s using gravity assists from Venus and Earth to get closer to the sun and to lift itself, gradually, out of the ecliptic plane. Around the middle of this decade, it’ll be high enough above the ecliptic plane to fly over the sun’s poles … something that’s never been done before.

Solar Orbiter had a Venus flyby in the early hours of Sunday, September 4, 2022. But on August 30, a mighty blast from the sun – a coronal mass ejection, or CME – left the sun, headed toward Venus. So this blast headed straight for Solar Orbiter, too. And it struck the spacecraft just two days before the craft’s closest approach to Venus.

The good news is that according to a report from the European Space Agency (ESA), a partner in the Solar Orbiter mission, the spacecraft was unharmed:

Fortunately, there were no negative effects on the spacecraft as the ESA-NASA solar observatory can withstand and in fact measure violent outbursts from our star …

EarthSky’s sun team talked about the August 30 CME in this post

And you can read the sun news from EarthSky every day

Yesterday, @ESASolarOrbiter flew by #Venus for a #GravityAssist that brings it 4.5 mil km closer to the Sun.

As the?? cosied up to the planet, the Sun flung an enormous coronal mass ejection straight at the pair??https://t.co/vuk7RLNItG#SpaceSafety? pic.twitter.com/4ts630F9b4

— ESA Operations (@esaoperations) September 5, 2022

Phew!

CMEs can be dangerous to spacecraft. They are powerful eruptions near the surface of the sun, driven by kinks in the solar magnetic field. If Earth happens to be in the path of a CME, the charged particles can slam into our atmosphere and create beautiful auroral displays. They can’t harm our human bodies here on Earth’s surface, because we’re protected by our planet’s blanket of atmosphere. But CMEs can disrupt satellites in Earth-orbit and even cause them to fail.

But Solar Orbiter is A-okay, ESA said. Because the spacecraft design not only withstands, but also measures, violent outbursts from the sun. In fact, understanding CMEs and tracking their progress through the solar system is part of Solar Orbiter’s mission. ESA said:

Data beamed home since Solar Orbiter encountered the solar storm shows how its local environment changed as the large CME swept by.

While some instruments had to be turned off during its close approach to Venus, to protect them from stray sunlight reflected off of the planet’s surface, Solar Orbiter’s ‘in situ’ instruments remained on, recording among other things an increase in solar energetic particles.

All in all, ESA sounded happy about the CME strike, especially after learning that Solar Orbiter weathered it so well.

Solar Orbiter’s Venus flybys

Sunday’s flyby of Venus took the spacecraft to within roughly 6,000 km (3,700 miles) of the planet. This particular gravity-assist will bring the spacecraft about 4.5 million km (2.8 million miles) closer to the sun than before, at its next perihelion (closest point to the sun).

Solar Orbiter’s orbit is in a resonance orbit with Venus. That means the spacecraft returns near Venus every few orbits, to use the planet’s gravity to alter the spacecraft’s path, or tilt its orbit out of the ecliptic plane.

Sunday’s close approach to Venus – the spacecraft’s third flyby – took place on Sunday at 01:26 UTC, when Solar Orbiter passed 12,500 km (7,800 miles) from the planet’s center, roughly 6,000 km (3,700 miles) from its gassy surface. Jose-Luis Pellon-Bailon, Solar Orbiter Operations Manager, said the flyby went according to plan:

By trading ‘orbital energy’ with Venus, Solar Orbiter has used the planet’s gravity to change its orbit without the need for masses of expensive fuel.

Bottom line: On September 4, 2022, two days before a close flyby of Venus, a CME or blast from the sun struck the sun-observing satellite Solar Orbiter.

Via ESA

The post CME strikes Solar Orbiter before Venus flyby first appeared on EarthSky.

Combined views from Webb and Hubble

The European Space Agency (ESA) released these images of M74 – aka the Phantom Galaxy – yesterday (August 29, 2022). On the left, you see a Hubble Space Telescope image. On the right, you see a James Webb Space Telescope image. The center image is a composite, created by combining Hubble’s optical data with Webb’s mid-infrared data.

ESA described what you see in the new image:

The red colors mark dust threaded through the arms of the galaxy, lighter oranges being areas of hotter dust. The young stars throughout the arms and the galaxy’s core are in blue. Heavier, older stars toward the galaxy’s center are cyan and green, projecting a spooky glow from the core of the Phantom Galaxy. Bubbles of star formation are also visible in pink across the arms. It’s rare to see such a variety of galactic features in a single image.

M74, the Phantom Galaxy

The Phantom Galaxy – Messier 74 or M74 – is around 32 million light-years away from Earth in the direction toward our constellation Pisces the Fishes.

It’s called the Phantom because the galaxy’s surface brightness is low. It’s the most difficult to find of all the Messier objects that amateur astronomers observe in small telerscopes. The low surface brightness is due to the fact that the galaxy lies almost face-on to Earth. Yet this orientation in space lets us see the galaxy’s two clearly defined spiral arms, which make it an example of a grand design spiral galaxy.

Astronomers estimate M74 hosts about 100 billion stars.

Bottom line: A new image of M74 – the Phantom Galaxy – combines data from the Hubble Space Telescope and the James Webb Space Telescope.

Via ESA

The post Webb and Hubble see the universe differently first appeared on EarthSky.

Drought has been crippling many regions of the world in Northern Hemisphere summer, 2022. While the shrinking Lake Mead and Lake Powell in the American West have gotten the lion’s share of press coverage here in the U.S., the issue is a global one. The BBC reported on August 24 that Europe’s drought is the worst in 500 years, and several famous European rivers have run dry. China’s largest freshwater lake and longest river are also running dry. The Guardian said on August 19 that drought in the Horn of Africa has the potential to push more than 22 million people into starvation.

Drought in Europe

The Global Drought Observatory released a report on August 22, 2022, that said two-thirds of Europe are under a drought warning. The lack of rainfall, plus persistent European heat waves, are expanding and worsening dry regions. The heat and drought has stressed summer crops, especially grain maize, soybeans and sunflowers. Forecasts continue to call for warmer and drier conditions in Europe into November.

The most visually dramatic effect of the drought in Europe is the dwindling levels in famous European rivers, as illustrated below:

Here’s a detailed look at the impact of #drought on France’s Loire River, with @planet images collected exactly a year apart on August 11 2021 & 2022. pic.twitter.com/ziyYh9Oosn

— Rob Simmon (@rsimmon) August 19, 2022

Drying rivers and lakes reveal secrets in Spain

The shrinking lakes and rivers are revealing sights long hidden in some parts of Europe. In Spain, the drought exposed a prehistoric stone circle, dubbed the Spanish Stonehenge, in a reservoir whose water level has dropped to 28% of capacity. Archaeologists believe that the circle of dozens of megalithic stones, officially called the Dolmen of Guadalperal, dates back to 5000 BCE. It currently sits fully exposed in one corner of the Valdecanas reservoir, in the central province of Cáceres.

Nazi ships revealed in Serbia

In Serbia, the receding waters of the Danube River near the town of Prahovo have uncovered dozens of World War II-era German warships, according to an August 19, 2022, Reuters report. Many of the ships still contain ammunition and explosive devices.

The vessels were among hundreds scuttled along the Danube by Nazi Germany's Black Sea fleet in 1944 as they retreated from advancing Soviet forces, and still hamper river traffic during low water levels 2/5 pic.twitter.com/PBsmgA53VZ

— Reuters (@Reuters) August 19, 2022

Czech’s hunger stone

In a small northern Czech town, close to the German border, lowering river water has revealed a rock inscribed with an eerie message. On August 19, 2022, The Guardian said:

As Europe’s rivers run dry in a devastating drought that scientists say could prove the worst in 500 years, their receding waters are revealing long-hidden artefacts, from Roman camps to ghost villages and second world war shipwrecks.

The so-called ‘hunger stone’ at Decín is one of dozens in central European rivers engraved to mark their levels during historic droughts, and warn future generations of the famine and hardship likely to follow each time they became visible.

How bad is the drought in Europe? Here's a famous “Hunger Stone” on the Elbe river in Germany. The oldest readable carving, from 1616, says: “Wenn du mich siehst, dann weine” – “If you see me, weep.” pic.twitter.com/kT5x9ESOOW

— ?? Ray Nayler ?? (he/him) (@raynayler) August 22, 2022

Shrinking reservoirs in the U.S. Southwest

On August 16, 2022, the Bureau of Reclamation said that 23 years of drought and low amounts of runoff have resulted in historically low water levels at the two largest reservoirs in the U.S., Lake Mead and Lake Powell on the U.S. Colorado river.

About 40 million people, across seven states and Mexico, rely on the Colorado River system for drinking water and to support livelihoods including farming and recreation.

As of August 24, 2022, Lake Powell stands at its lowest level since it was filled in the mid-1960s, at just 26 percent of capacity, its lowest point since 1967. NASA Earth Observatory reported:

Downstream from Lake Powell, water storage at Lake Mead on August 22 stood at 28 percent of capacity, and the entire Colorado river system held just 34 percent. At the same time, roughly 86 percent of the land area across nine western states was affected by some level of drought, according to the August 16 report from the U.S. Drought Monitor.

Drying Lake Mead reveals bodies and boats

Water levels in Lake Mead – the largest reservoir in the U.S. – are at their lowest since the completion of the Hoover Dam in the 1930s, which stopped the flow of the Colorado River and created this lake in the desert. The retreating lake is revealing things hidden underwater for decades. People are finding trash, boats (including a World War II-era craft) and human bodies. In fact, Newsweek reported that officials said there are probably 100s of bodies waiting to be found in Lake Mead.

BREAKING: 5th body at Lake Mead.
That's 5 since May.
Full story here from @CBSMornings https://t.co/9zBvBOB6dR https://t.co/fgdddHlSuf

— Dave Malkoff (@malkoff) August 16, 2022

Dinosaur tracks in Texas

Dry conditions have lowered water levels at Texas’s Dinosaur Valley State Park, revealing 113 million-year-old dinosaur tracks in the Paluxy River riverbed.

The tracks, preserved in limestone, are usually covered by water and sediment. However, months of hot, dry conditions have turned rivers and creeks to puddles in places, exposing the prints. Park Superintendent Jeff Davis told The Hill:

You can actually see their individual toes, their individual claw marks. You can even see where they slipped as they were running.

Woah! ?? A spokesperson for Dinosaur Valley State Park said the tracks belong to the Acrocanthosaurus, which would stand, as an adult, about 15 feet tall and weigh close to seven tons.
READ MORE: https://t.co/wXOf74RWBq pic.twitter.com/ScrXvyFgYW

— ABC13 Houston (@abc13houston) August 23, 2022

Drought in China

China has been breaking heat records all summer. And the extreme temperatures and low rainfall have created a prolonged drought in China. The Yangtze River – longest river in China and third longest in the world – is withering away. The river basin is home to 450 million people and 1/3 of China’s crops, and the people there are dealing with depleted wells and brush fires.

China’s largest freshwater lake, Poyang, is also drying up. It’s now less than 25% of its normal surface area. A view from an airplane shows the water in the lake to have dwindled down into a shape that some of the locals are calling The Tree of Death.

#LoMásVisto ••• El calor intenso redujo los niveles de agua del lago #Poyang, en #China, provocando que simulara ramas de árboles. Estas imágenes se hicieron virales por su perfección en las formas. pic.twitter.com/nhuZ1RMvb3

— Portavoz (@PortavozEdoMex) August 24, 2022

Standing in the middle of China’s largest fresh water lake. #Poyang #tadhothere pic.twitter.com/VSAnxpkSGu

— ??? (@PaddyFok) August 25, 2022

Europe and the US not the only Drought stricken regions. The Yangtze River in China has shrunken to half its normal width. They’ve had to close canals supplied by this water. pic.twitter.com/fOE66uGMik

— Peter Dynes (@PGDynes) August 19, 2022

Shocking pictures from China: World’s third-largest river dries up in drought ?pic.twitter.com/1rXKa01quq

— Daniel Moser (@_dmoser) August 23, 2022

Drought in the Horn of Africa

Four years of failed rains in Kenya, Somalia and Ethiopia have left the Horn of Africa facing catastrophe, The Guardian said. The drought puts 22 million people at risk of starvation by September, according to an August 19, 2022, report from the United Nation’s World Food Programme (WFP). The region is seeing the worst drought conditions in 40 years, with no end in sight.

For all the talk about drought in the US, Europe and China – let’s not forget the drought in East Africa threatens starvation for up to 20 million people. That is the most urgent emergency needing addressed due to disappearing fresh water sources. pic.twitter.com/T1ZnfGKlI0

— Peter Dynes (@PGDynes) August 22, 2022

Drought in the Horn of Africa is the driest conditions & hottest temperatures since satellite record-keeping began.

Impacting 13 million people currently, women & children walk about 14 km looking for water & animals are dying in hundreds of thousands. This is a climate crisis! pic.twitter.com/DYd44M1X2S

— MulindwaMoses (@mulindwa_guy) August 21, 2022

Horn of Africa: @wfp scales up assistance as unprecedented drought raises levels of hunger and the threat of famine.

Up to 22 million people are now struggling to find enough food to eat across Ethiopia, Kenya and Somalia. https://t.co/sQnCua24EV

— United Nations (@UN) August 22, 2022

Bottom line: Drought is crippling many regions of the world in 2022, from the US and Europe to China and the Horn of Africa. As waters recede, ancient artifacts are appearing.

The post Drought around the world, August 2022, in dramatic images first appeared on EarthSky.