news sciences

On and in extinction

We study Earth’s history by studying the record of past events that is preserved in the rocks. Image via Guy Ottewell.

Re-printed with permission from Guy Ottewell’s blog; click here to visit him.

We are now on what is called the Jurassic Coast, on the English Channel coast of southern England. It was given this title after it became a UNESCO World Heritage Site in 2001. Jurassic is the name of just one of a group of three geological layers, but it’s the one more popularly known because of the 1993 film Jurassic Park, so is good for tourism.

The three layers – Triassic, Jurassic, and Cretaceous – underlie much of England, and became tilted so that they slope gently down toward the east. They are collectively called the Mesozoic (which means middle life); the era in which they were laid down is also known as the Age of Dinosaurs. It lasted from about 250 million to about 65 million years ago. The three layers outcrop along this coast in cliffs, from which fossils are loosened by tides and landslips, so Lyme Regis, in the middle of the Jurassic Coast, is a mecca for geologists.

Location of the Jurassic Coast in England, via Wikipedia.

What happened 250 million years ago to begin the Mesozoic? The time period is known as the Permian-Triassic extinction, when 70 percent of all life on land, and 90 percent of all life in the oceans, was wiped out. The causes aren’t known precisely, but massive volcanic eruptions in what is now Siberia were involved. Carbon dioxide was forced into the oceans, and oxygen forced out. Marine life asphyxiated.

Life had previously been diverse. It had radiated in the Cambrian explosion – an event some 541 million years ago, when most major animal phyla appeared in the fossil record – into all the lineages that still exist and many that do not.

Perhaps, if the great extinction hadn’t happened, we would be 250 million years more advanced than we now are.

Life began thriving and diversifying again, through the Triassic, Jurassic, and Cretaceous periods. Then about 65 million years ago came another extinction, called the Cretaceous-Paleogene. It was more scary than Jurassic Park but maybe not quite as drastic as the earlier event: it extinguished three quarters of species. It is thought to have been caused by an asteroid that hit the Yucatán, and is more popularly known, because it killed all dinosaurs except the birds.

We are living spatially above the traces of those global extinctions, and, in time, within another, between the recent geological period called the Holocene and what is coming to be called a new one, the Anthropocene. It began with agriculture, and has been accelerating since the industrial revolution. Carbon dioxide is again being forced into the oceans, so that corals are dying.

Of the world’s mammals, 36 percent, by mass, are now of one species, the human. I’ve read that 60 percent are livestock grown for human use (cattle, sheep, pigs). Wild mammals (everything from whales to elephants to lions to lemurs to mice) are reduced to 4 percent. Of birds, 70 percent by mass are livestock (poultry); wild birds are down to 30 percent. These are among the findings of the first thorough assessment of the world’s biomass, reported on May 21, 2018 in the Proceedings of the National Academy of Sciences of the U.S.A.

No need to repeat the statistics of the declines of fish, amphibians, bees, of which you’ve doubtless read. A recent shock was the decimation in European countries, probably extrapolable to others, of all flying insects, on which the higher food chain depends.

I’m not sure how the ongoing extinction event compares with the Permian-Triassic one in speed and scale. But it shouldn’t be as bad. Its cause is not a blind volcanic force but a cognitive species, which will presumably understand and change its behavior before those percentages reach their worst.

Image from a film called Welcome to the Anthropocene, commissioned by the Planet Under Pressure conference, London, March, 2012.

Bottom line: There have been multiple mass extinctions in Earth’s history. Signs point to our living in the midst of one now?

Source: The biomass distribution on Earth

3rd of this season’s 3 full moons May 29

Above: Moon set over La Paz, capital city of Bolivia, on April 30, 2018 from Max Glaser.

May 29, 2018 ushers in the third of this season’s three full moons. In this case, when we say season, we mean the time period between an equinox and solstice. The March equinox was March 20. We had full moons on March 31, and April 30, and now this May 29 full moon. Most seasons, in fact, do have three full moons, and all full moons have names. Every so often, there’s a season with four full moons, and then a full moon lacks a moon name. In that case, one of those full moons carries the name Blue Moon. More about that below.

In the Northern Hemisphere, we call the May full moon a Flower Moon, Planting Moon or Milk Moon. In the Southern Hemisphere, this same full moon is the Hunter’s Moon, Beaver Moon or Frost Moon.

For the Northern Hemisphere, this May 2018 full moon counts as the final full moon of spring.

For the Southern Hemisphere, this May 2018 full moon is the final full moon of autumn.

The moon wasn’t quite full, but it looked nearly round and full in the sky – near the planet Jupiter, visible here just above the ridge of the mountain – in this May 28, 2018 photo (3:40 a.m.) by Asthadi Setyawan in Malang, East Java, Indonesia.

What about next year? Checking the moon phase almanac, we find that – a year from now – a full moon happens on May 18, 2019. There’s another full moon on June 17, 2019. Throughout the 21st century (2001 to 2100) the June solstice falls on June 20 or 21. For that reason, we know that the 2019 June full moon will happen before the June 2019 solstice.

As it turns out, the 2019 May full moon will be the third of four full moons in between the March 2019 equinox and June 2019 solstice. The June 2019 full moon will be the fourth of that season’s four full moons. As mentioned above, most seasons have three full moons. But not so between the March equinox and June solstice of 2019:

Equinox: March 20, 2019
Full moon: March 21, 2019
Full moon: April 19, 2019
Full moon: May 18, 2019
Full moon: June 17, 2019
Solstice: June 21, 2019

By tradition, the third of a season’s four full moons is sometimes called a Blue Moon. Four full moons in one season is relatively rare. In a period of 19 calendar years, there are 76 seasons (19 x 4 = 76), yet only 7 of these 76 seasons have four full moons.

This was the April 2018 full moon. Kwong Liew composed this image of 5 shots taken on April 29 over Salesforce Tower in San Francisco.

Bottom line: In 2018, we have 3 full moons between the March equinox and June solstice. Exactly 12 full moons from now – in May 2019 – we’ll be enjoying the 3rd of 4 full moons of this season. People will call it a Blue Moon.

Resources:

Phases of the moon: 2001 to 2100

Solstices and equinoxes: 2001 to 2100

from EarthSky https://ift.tt/2xvTnjd

Above: Moon set over La Paz, capital city of Bolivia, on April 30, 2018 from Max Glaser.

In the Northern Hemisphere, we call the May full moon a Flower Moon, Planting Moon or Milk Moon. In the Southern Hemisphere, this same full moon is the Hunter’s Moon, Beaver Moon or Frost Moon.

For the Northern Hemisphere, this May 2018 full moon counts as the final full moon of spring.

For the Southern Hemisphere, this May 2018 full moon is the final full moon of autumn.

Equinox: March 20, 2019
Full moon: March 21, 2019
Full moon: April 19, 2019
Full moon: May 18, 2019
Full moon: June 17, 2019
Solstice: June 21, 2019

This was the April 2018 full moon. Kwong Liew composed this image of 5 shots taken on April 29 over Salesforce Tower in San Francisco.

Resources:

Phases of the moon: 2001 to 2100

Solstices and equinoxes: 2001 to 2100

from EarthSky https://ift.tt/2xvTnjd

Learning from a cancer’s past could predict its future

Complaining about the weather is a favourite pastime for many. And while we can’t change it, the forecast gives us the opportunity to think ahead, plan and make sensible choices. Whether that’s a change of outfit or using a different mode of transport, knowing what might lie ahead allows us to be prepared for what’s predicted.

This is exactly where we want to be with cancer. Except that if we can predict how a cancer will behave over time, perhaps we can change its future, for the better.

We’re looking into the future, to know what a tumour will look like next week, month or even year.

– Professor Graham

A new study led by Cancer Research UK scientists takes us a step towards that goal. Published in Nature Genetics, they’ve used computers and genetic data to piece together a cancer’s history, allowing them to develop a way to predict the next steps that the tumour will likely take as it progresses.

“We’re revealing the secret history of a tumour, which we were never able to observe before,” says lead researcher Professor Trevor Graham, from the Barts Cancer Institute in London.

“But the biggest thing about this work is that we’re looking into the future, to know what a tumour will look like next week, month or even year.”

That offers the chance that doctors could one day tailor treatment options in individual patients based on the predictions, keeping them one step ahead of the game. That’s a distant goal, but this work helps carve a path to get there.

Past, present, and future

It’s no surprise that this research has its roots in Charles Darwin’s theory of evolution. Just like how a species changes as it adapts to its environment, so too does a growing tumour.

Scientists have been studying this process in species for many years. Thanks to sophisticated technology that reads an organism’s DNA – alongside the computers and equations that quickly analyse the data – researchers can look back in time at a species’ evolutionary history, and its relationship with others.

And it’s the same tools that make this possible for cancer too.

“We haven’t invented new maths,” says co-leading author Dr Andrea Sottoriva, a Cancer Research UK Fellow from the Institute of Cancer Research, London. “We’ve taken what others have built over the past few decades to study various populations, and applied this maths to cancer.”

By unravelling a tumour’s past, the team hoped to understand more about what its future may hold. But as tumours are often studied at a single point in time, using a biopsy sample taken from a cancer that has already developed, the team needed to come up with a way to turn back the clock.

“The processes that took place before it was removed, how it grew, were previously invisible to us,” says Graham.

So, the team turned their attention to existing data, making use of detailed genetic samples taken from tumours. They first began with DNA code read from just three patients – one with breast cancer, one with leukaemia, and one with lung cancer.

Cancer’s secret diary

When a cancer grows its cells develop new genetic changes, meaning that one part of a tumour could have different genetic patterns to another. Studying this variety in the samples was key to this work.

“The question we wanted to answer was: ‘how did that variety arise in the first place? Did it grow this way, or did it grow that way?’” Graham says.

Using maths that plots how a species evolves over time, the researchers built a computer simulation for the tumours. They then compared these different evolutionary scenarios to the genetic data from the patients, matching the scenarios that gave the same result.

A cancer’s genetic information… is like a secret diary that records the dynamics that have happened over time.

– Professor Graham

From these matches, the researchers found the evolutionary path the cancers had likely taken, giving rise to the diversity that was found in each biopsy sample.

Next, they looked at 4 large groups of patient samples, spanning bowel, stomach and lung cancers, and also samples taken from cancer that had spread. These showed that genetic changes which give a cancer cell an advantage, such as being able to grow faster, emerge early in the tumour’s development. But they also found that this process was still taking place in tumours that had spread, which could be caused by cells adapting to cancer treatment.

“A cancer’s genetic information is a snapshot in time, telling you what the tumour looks like today,” says Graham. “But it’s also like a secret diary that records the dynamics that have happened over time.

“We’re using this to learn something about the rules of cancer evolution.”

Written in the rules

The team realised they could turn these rules into a way to predict how the cancers may evolve in the future. By running millions of simulations of tumour growth on computers, and seeing if their rules could forecast how these virtual cancers progressed, Graham is building confidence in their predictions.

“Once you know the rules, you can play the game,” Sottoriva says.

Once you know the rules, you can play the game.

– Dr Andrea Sottoriva

“What we’ve done is enable predictions about cancer progression to hopefully be made in patients, so that treatment decisions could be made based on what the tumour will look like in the future, rather than today.

“But we haven’t yet proven that’s possible.”

Next, they need to prove this technique’s accuracy. And to do that, the researchers need to be able to track cancer evolution over time in the lab, and see if it matches their forecasts. And there’s another key aspect that’s so far missing from this work: how treatment might impact a cancer’s evolutionary path. Finding that out is also next on their to-do list.

Research is like the weather. We don’t know what the future holds. But in making predictions based on the evidence we have, an exciting and important journey of discovery awaits.

Justine

Williams, M. J. et al. Quantification of subclonal selection in cancer from bulk sequencing data. Nature Genetics. https://ift.tt/2kwCdZn.

from Cancer Research UK – Science blog https://ift.tt/2IUFqjR

This is exactly where we want to be with cancer. Except that if we can predict how a cancer will behave over time, perhaps we can change its future, for the better.

We’re looking into the future, to know what a tumour will look like next week, month or even year.

– Professor Graham

“We’re revealing the secret history of a tumour, which we were never able to observe before,” says lead researcher Professor Trevor Graham, from the Barts Cancer Institute in London.

“But the biggest thing about this work is that we’re looking into the future, to know what a tumour will look like next week, month or even year.”

Past, present, and future

It’s no surprise that this research has its roots in Charles Darwin’s theory of evolution. Just like how a species changes as it adapts to its environment, so too does a growing tumour.

And it’s the same tools that make this possible for cancer too.

“The processes that took place before it was removed, how it grew, were previously invisible to us,” says Graham.

Cancer’s secret diary

“The question we wanted to answer was: ‘how did that variety arise in the first place? Did it grow this way, or did it grow that way?’” Graham says.

A cancer’s genetic information… is like a secret diary that records the dynamics that have happened over time.

– Professor Graham

From these matches, the researchers found the evolutionary path the cancers had likely taken, giving rise to the diversity that was found in each biopsy sample.

“We’re using this to learn something about the rules of cancer evolution.”

Written in the rules

“Once you know the rules, you can play the game,” Sottoriva says.

Once you know the rules, you can play the game.

– Dr Andrea Sottoriva

“But we haven’t yet proven that’s possible.”

Research is like the weather. We don’t know what the future holds. But in making predictions based on the evidence we have, an exciting and important journey of discovery awaits.

Justine

Williams, M. J. et al. Quantification of subclonal selection in cancer from bulk sequencing data. Nature Genetics. https://ift.tt/2kwCdZn.

from Cancer Research UK – Science blog https://ift.tt/2IUFqjR

Lightning sprites over Oklahoma

Paul Smith said this image is a still from a video.

Lightning sprites are offshoots of large-scale electrical discharges taking place high in Earth’s atmosphere, above thunderstorms. They’re often red in color, and so they’re sometimes called red sprites. They can be tens of miles high, but last only a few tens of milliseconds. Oklahoma – which lies within an area of the Great Plains known as Tornado Alley – is a good place to see lightning sprites. Paul Smith in Edmond, Oklahoma of a longtime observer of them, and he captured this image on May 24, 2018. He told EarthSky:

My best sprite lightning capture to date. A beautiful jellyfish, close range from Highway 33 East of Kingfisher, Oklahoma on the morning of May 24 at 12:55 a.m. local time, looking northwest towards Alva, Oklahoma.

You can even see the color change in the tendrils going into the lower atmosphere.

Thank you, Paul!

Want to see lightning sprites in real time? The video below, from Thomas Ashcraft in New Mexico – another veteran lighting sprite observer – captured it on June 23, 2014.

Sequence 01 from Thomas Ashcraft on Vimeo.

Bottom line: May 2018 example of sprite lightning over Oklahoma.

from EarthSky https://ift.tt/2JaWvp7

Paul Smith said this image is a still from a video.

My best sprite lightning capture to date. A beautiful jellyfish, close range from Highway 33 East of Kingfisher, Oklahoma on the morning of May 24 at 12:55 a.m. local time, looking northwest towards Alva, Oklahoma.

You can even see the color change in the tendrils going into the lower atmosphere.

Thank you, Paul!

Want to see lightning sprites in real time? The video below, from Thomas Ashcraft in New Mexico – another veteran lighting sprite observer – captured it on June 23, 2014.

Sequence 01 from Thomas Ashcraft on Vimeo.

Bottom line: May 2018 example of sprite lightning over Oklahoma.

from EarthSky https://ift.tt/2JaWvp7

When was Earth’s 1st snow?

Image via quotesgram.

Earth’s first snow might have fallen after large masses of land rose swiftly from the sea and set off dramatic changes on our planet 2.4 billion years ago. That’s according to a study published May 24, 2018, in the peer-reviewed journal Nature.

Geologist Ilya Bindeman is a professor in the Department of Earth Sciences at University of Oregon and the study lead author. He said in a statement:

What we speculate is that once large continents emerged, light would have been reflected back into space and that would have initiated runaway glaciation. Earth would have seen its first snowfall.

Previously submerged surfaces become exposed to weathering, leading to the accumulation of mudrocks and shales. In this scene, winter drainage at Fern Ridge Reservoir west of Eugene, Oregon, exposes mudrocks, providing an example of how newly risen land is exposed to weathering forces. Image via Ilya Bindeman.

The research team studied shale, Earth’s most abundant sedimentary rock. Shale rocks are formed by the weathering of crust. Bindeman said:

They tell you a lot about the exposure to air and light and precipitation. The process of forming shale captures organic products and eventually helps to generate oil. Shales provide us with a continuous record of weathering.

Using shale samples from every continent, the scientists looked at ratios of three common oxygen isotopes, or chemical signatures. They found evidence from as far back as 3.5 billion years ago showing traces of rainwater that caused weathering of land.

Bindeman and his team detected a major shift in the chemical makeup of 278 shale samples at the 2.4-billion-year mark. Their research suggests that those changes began when Earth was much hotter than today, when the newly-surfaced land rose rapidly and was exposed to weathering. Bindeman said the total landmass of the planet 2.4 billion years ago may have reached about two-thirds of what is seen today.

The emergence of so much land changed the flow of atmospheric gases and other chemical and physical processes, say the researchers, primarily between 2.4 billion and 2.2 billion years ago, he said.

The chemical changes recorded in the rocks coincide with the theorized timing of land collisions that formed one of Earth’s first supercontinents, Kenorland, and the planet’s first high mountain ranges and plateaus. Bindeman said:

Land rising from water changes the albedo of the planet. Initially, Earth would have been dark blue with some white clouds when viewed from space. Early continents added to reflection.

Earth’s albedo is the proportion of sunlight that’s reflected by the planet’s surface.

Before and after: How Earth’s land elevations may have looked before and after the Great Oxygenation Event. Image via Ilya Bindeman.

The rapid changes, the researchers noted, may have triggered what scientists call the Great Oxygenation Event, in which atmospheric changes brought significant amounts of free oxygen into the air.

Bottom line: A new study suggests Earth got its first snowfall 2.4 billion years ago.

Does Planet Nine exist? Astronomers point to new evidence

Diagram depicting the orbit of 2015 BP519 (Caju), which has the highest inclination of any extreme trans-Neptunian object discovered to date. Its unusual perpendicular orbit may be evidence for Planet Nine. Image via Phys.Org.

Is there a ninth major planet lurking in the outer reaches of our solar system? This question has become one of the most hotly debated in planetary science. The idea of a large, unknown Planet Nine residing so far from the sun that it hasn’t yet been discovered is certainly tantalizing. So far, there’ve been hints as to its existence, but no confirmation yet. We might be getting closer to finding it, however. Last week, an international team of researchers presented additional evidence, detailed in a new study, suggesting that Planet Nine is influencing the behavior of an oddball object – 2015 BP519 (aka Caju) – in the outer solar system.

Astronomers at Caltech had previously calculated the likely existence of a large ninth planet (sorry, Pluto) in the outer fringes of the solar system, based on the orbits of smaller icy objects. Their orbits were being perturbed by the gravitational influence of … something.

According to the astronomers’ calculations, the as-yet-undiscovered planet should be about four times the size of Earth and 10 times its mass. That would make it similar to super-Earth exoplanets found orbiting other stars. And that would be interesting, since many super-Earths have now been discovered, although there were none to be seen in our own solar system. But maybe there is one after all, so far from the sun that it has remained hidden.

Such a discovery would be very exciting, since super-Earths are larger than Earth but smaller than Uranus or Neptune, different from anything else in our solar system. If a large Planet Nine is there, it is very far away, much farther than Pluto. If it exists, it likely takes about 10,000 to 20,000 years to complete one orbit around the sun.

Planet Nine may be a super-Earth, a type of exoplanet found orbiting many stars. They are rocky and larger than Earth, but smaller than Uranus or Neptune. Image via NASA/JPL.

Astronomers first discovered 2015 BP519 (Caju) three years ago. It is a trans-Neptunian object (TNO), which, generally speaking, are minor planets orbiting the sun beyond the orbit of Neptune. Caju is one of only a dozen or so known objects that are categorized as extreme trans-Neptunian objects (ETNOs). Such objects have a semi-major axis greater than 150 astronomical units (AU) and a perihelion – closest point to the sun – greater than 30 AU. Caju’s estimated diameter is 248-434 miles (400-700 km), making it a potential dwarf planet. So it is a very interesting object.

What’s more, since its discovery, further analysis has shown that Caju has an unusual orbit, which lies almost perpendicular to all the known planets. In fact, Caju has the highest inclination of any TNO discovered so far.

Amazingly, just such an object had been predicted by computer models performed by the team searching for Planet Nine. Caltech astronomer Mike Brown, who wasn’t part of the new study, but who is active in Planet Nine research, told PopSci.com on May 22, 2018:

I’m pretty excited about the new object. It is the predicted link between the very distant elongated orbits that we’ve known about and the much closer tilted orbits that we’ve seen.

Thus Caju adds to a growing body of evidence for the elusive Planet Nine, which – if really there – still remains out of sight for astronomers. Astronomer Konstantin Batygin – who, along with Brown, first gave Planet Nine a name, size and distance – told Space.com on May 21 that, as of October 2017, there were at least five lines of evidence pointing to Planet Nine’s existence. Earlier, in 2017, astronomers had found evidence that 22 other TNOs seemed to have their orbits perturbed by another large unseen planet. Batygin said:

If you were to remove this explanation and imagine Planet Nine does not exist, then you generate more problems than you solve. All of a sudden, you have five different puzzles, and you must come up with five different theories to explain them.

Illustration showing the hypothesized orbit of Planet Nine along with the known orbits of several TNOs. Image via R. Hurt/JPL-Caltech.

Bottom line: While Planet Nine still hasn’t been confirmed, the evidence is growing that just maybe, an as-yet-unseen large planet does indeed prowl the desolate outer fringes of our solar system.

Source: Discovery and Dynamical Analysis of an Extreme Trans-Neptunian Object with a High Orbital Inclination

Via Phys.org

from EarthSky https://ift.tt/2sdmXoh

Planet Nine may be a super-Earth, a type of exoplanet found orbiting many stars. They are rocky and larger than Earth, but smaller than Uranus or Neptune. Image via NASA/JPL.

I’m pretty excited about the new object. It is the predicted link between the very distant elongated orbits that we’ve known about and the much closer tilted orbits that we’ve seen.

If you were to remove this explanation and imagine Planet Nine does not exist, then you generate more problems than you solve. All of a sudden, you have five different puzzles, and you must come up with five different theories to explain them.

Illustration showing the hypothesized orbit of Planet Nine along with the known orbits of several TNOs. Image via R. Hurt/JPL-Caltech.

Bottom line: While Planet Nine still hasn’t been confirmed, the evidence is growing that just maybe, an as-yet-unseen large planet does indeed prowl the desolate outer fringes of our solar system.

Source: Discovery and Dynamical Analysis of an Extreme Trans-Neptunian Object with a High Orbital Inclination

Via Phys.org

from EarthSky https://ift.tt/2sdmXoh

Waiting for tomorrow

Image via Tommy Richardsen.

Tommy told us:

I shot this in June last year. After having spent hours on a beach nearby trying to get a shot with rather boring clouds, it finally started to break up once I got here. The Skjervøy area has a lot of interesting mountains, rivers, lakes and even glaciers. Finding an interesting place is not hard, getting interesting weather may be hard at times.

Bottom line: Photo of Skjervøy in northern Norway.

from EarthSky https://ift.tt/2ISwjjW

Image via Tommy Richardsen.

Tommy told us:

I shot this in June last year. After having spent hours on a beach nearby trying to get a shot with rather boring clouds, it finally started to break up once I got here. The Skjervøy area has a lot of interesting mountains, rivers, lakes and even glaciers. Finding an interesting place is not hard, getting interesting weather may be hard at times.

Bottom line: Photo of Skjervøy in northern Norway.

from EarthSky https://ift.tt/2ISwjjW