Tons of acorns in your yard? It must be a mast year

A mast year can be a squirrel’s dream come true. Image via Editor77/Shutterstock.com.

By Emily Moran, University of California, Merced

If you have oak trees in your neighborhood, perhaps you’ve noticed that some years the ground is carpeted with their acorns, and some years there are hardly any. Biologists call this pattern, in which all the oak trees for miles around make either lots of acorns or almost none, “masting.”

EarthSky 2020 lunar calendars are available! They make great gifts. Order now. Going fast!

A dipterocarp seed. Image via kumakumalatte/Shutterstock.com.

In New England, naturalists have declared this fall a mast year for oaks: All the trees are making tons of acorns all at the same time.

Many other types of trees, from familiar North American species such as pines and hickories to the massive dipterocarps of Southeast Asian rainforests, show similar synchronization in seed production. But why and how do trees do it?

Benefits of synchronized seeds

Every seed contains a packet of energy-rich starch to feed the baby tree that lies dormant inside. This makes them a tasty prize for all sorts of animals, from beetles to squirrels to wild boar.

If trees coordinate their seed production, these seed-eating animals are likely to get full long before they eat all the seeds produced in a mast year, leaving the rest to sprout.

For trees like oaks that depend on having their seeds carried away from the parent tree and buried by animals like squirrels, a mast year has an extra benefit. When there are lots of nuts, squirrels bury more of them instead of eating them immediately, spreading oaks across the landscape.

Getting in sync

It’s still something of a mystery how trees synchronize their seed production to get these benefits, but several elements seem to be important.

First, producing a big crop of seeds takes a lot of energy. Trees make their food through photosynthesis: using energy from the Sun to turn carbon dioxide into sugars and starch. There’s only so many resources to go around, though. Once trees make a big batch of seeds, they may need to switch back to making new leaves and wood for a while, or take a year or two to replenish stored starches, before another mast.

But how do individual trees decide when that mast year should be? Weather conditions appear to be important, especially spring weather. If there’s a cold snap that freezes the flowers of the tree – and yes, oaks do have flowers, they’re just extremely small – then the tree can’t produce many seeds the following fall.

Harm to the tree’s flowers in spring doesn’t bode well for the acorn crop come fall. Image via almgren/Shutterstock.com.

A drought during the summer could also kill developing seeds. Trees will often shut the pores in their leaves to save water, which also reduces their ability to take in carbon dioxide for photosynthesis.

Because all the trees within a local area are experiencing essentially the same weather, these environmental cues can help coordinate their seed production, acting like a reset button they’ve all pushed at the same time.

A third intriguing possibility that researchers are still investigating is that trees are “talking” to each other via chemical signals. Scientists know that when a plant is damaged by insects, it often releases chemicals into the air that signal to its other branches and to neighboring plants that they should turn on their defenses. Similar signals could potentially help trees coordinate seed production.

Investigation of tree-to-tree communication is still in its infancy, however. For instance, ecologists recently found that chemicals released from the roots of the leafy vegetable mizuna can affect the flowering time of neighboring plants. While this sort of communication is unlikely to account for the rough synchronization of seed production over dozens or even hundreds of miles, it could be important for syncing up a local area.

Lots of nuts is good news for the animals that eat them, and the animals who eat them. Image via TessarTheTegu/Shutterstock.com.

Masting’s effects ripple through the food web

Whatever the causes, masting has consequences that flow up and down the food chain.

For instance, rodent populations often boom in response to high seed production. This in turn results in more food for rodent-eating predators like hawks and foxes; lower nesting success for songbirds, if rodents eat their eggs; and potentially higher risk of transmission of diseases like hantavirus to people.

If the low seed year that follows causes the rodent population to collapse, the effects are reversed.

The seeds of masting trees have also historically been important for feeding human populations, either directly or as food for livestock. Acorns were a staple in the diet of Native Americans in California, with families carefully tending particular oaks and storing the nuts for winter. In Spain, the most prized form of ham still comes from pigs that roam through the oak forests, eating up to 20 pounds of acorns each day.

Sometimes the ground seems paved in acorns. Image via kurutanx/Shutterstock.com.

So the next time you take an autumn walk, check out the ground under your local oak tree – you might just see the evidence of this amazing process.

Emily Moran, Assistant Professor of Life and Environmental Sciences, University of California, Merced

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Bottom line: Explanation of masting: the pattern of trees for miles around synchronizing to all produce lots of seeds – or very few.

from EarthSky https://ift.tt/349OUOH

A mast year can be a squirrel’s dream come true. Image via Editor77/Shutterstock.com.

By Emily Moran, University of California, Merced

If you have oak trees in your neighborhood, perhaps you’ve noticed that some years the ground is carpeted with their acorns, and some years there are hardly any. Biologists call this pattern, in which all the oak trees for miles around make either lots of acorns or almost none, “masting.”

EarthSky 2020 lunar calendars are available! They make great gifts. Order now. Going fast!

A dipterocarp seed. Image via kumakumalatte/Shutterstock.com.

In New England, naturalists have declared this fall a mast year for oaks: All the trees are making tons of acorns all at the same time.

Many other types of trees, from familiar North American species such as pines and hickories to the massive dipterocarps of Southeast Asian rainforests, show similar synchronization in seed production. But why and how do trees do it?

Benefits of synchronized seeds

Every seed contains a packet of energy-rich starch to feed the baby tree that lies dormant inside. This makes them a tasty prize for all sorts of animals, from beetles to squirrels to wild boar.

If trees coordinate their seed production, these seed-eating animals are likely to get full long before they eat all the seeds produced in a mast year, leaving the rest to sprout.

For trees like oaks that depend on having their seeds carried away from the parent tree and buried by animals like squirrels, a mast year has an extra benefit. When there are lots of nuts, squirrels bury more of them instead of eating them immediately, spreading oaks across the landscape.

Getting in sync

It’s still something of a mystery how trees synchronize their seed production to get these benefits, but several elements seem to be important.

First, producing a big crop of seeds takes a lot of energy. Trees make their food through photosynthesis: using energy from the Sun to turn carbon dioxide into sugars and starch. There’s only so many resources to go around, though. Once trees make a big batch of seeds, they may need to switch back to making new leaves and wood for a while, or take a year or two to replenish stored starches, before another mast.

But how do individual trees decide when that mast year should be? Weather conditions appear to be important, especially spring weather. If there’s a cold snap that freezes the flowers of the tree – and yes, oaks do have flowers, they’re just extremely small – then the tree can’t produce many seeds the following fall.

Harm to the tree’s flowers in spring doesn’t bode well for the acorn crop come fall. Image via almgren/Shutterstock.com.

A drought during the summer could also kill developing seeds. Trees will often shut the pores in their leaves to save water, which also reduces their ability to take in carbon dioxide for photosynthesis.

Because all the trees within a local area are experiencing essentially the same weather, these environmental cues can help coordinate their seed production, acting like a reset button they’ve all pushed at the same time.

A third intriguing possibility that researchers are still investigating is that trees are “talking” to each other via chemical signals. Scientists know that when a plant is damaged by insects, it often releases chemicals into the air that signal to its other branches and to neighboring plants that they should turn on their defenses. Similar signals could potentially help trees coordinate seed production.

Investigation of tree-to-tree communication is still in its infancy, however. For instance, ecologists recently found that chemicals released from the roots of the leafy vegetable mizuna can affect the flowering time of neighboring plants. While this sort of communication is unlikely to account for the rough synchronization of seed production over dozens or even hundreds of miles, it could be important for syncing up a local area.

Lots of nuts is good news for the animals that eat them, and the animals who eat them. Image via TessarTheTegu/Shutterstock.com.

Masting’s effects ripple through the food web

Whatever the causes, masting has consequences that flow up and down the food chain.

For instance, rodent populations often boom in response to high seed production. This in turn results in more food for rodent-eating predators like hawks and foxes; lower nesting success for songbirds, if rodents eat their eggs; and potentially higher risk of transmission of diseases like hantavirus to people.

If the low seed year that follows causes the rodent population to collapse, the effects are reversed.

The seeds of masting trees have also historically been important for feeding human populations, either directly or as food for livestock. Acorns were a staple in the diet of Native Americans in California, with families carefully tending particular oaks and storing the nuts for winter. In Spain, the most prized form of ham still comes from pigs that roam through the oak forests, eating up to 20 pounds of acorns each day.

Sometimes the ground seems paved in acorns. Image via kurutanx/Shutterstock.com.

So the next time you take an autumn walk, check out the ground under your local oak tree – you might just see the evidence of this amazing process.

Emily Moran, Assistant Professor of Life and Environmental Sciences, University of California, Merced

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Bottom line: Explanation of masting: the pattern of trees for miles around synchronizing to all produce lots of seeds – or very few.

from EarthSky https://ift.tt/349OUOH

Urine tests: detecting cancer in pee

Feeling anxious around needles is common. The NHS estimates that around 1 in 10 people experience trypanophobia, a fear of medical procedures that involve needles or injections.

Unfortunately, in medicine, the use of needles is often necessary to check on a person’s health. But looking in the blood may not be the only way to find clues left behind by disease. Other bodily fluids, like urine, also have the potential to reveal what’s going on in our bodies.

“Urine gives a great insight into what’s going on inside our bodies,” says Mr Richard Bryan from the University of Birmingham, a Cancer Research UK-funded bladder cancer surgeon who’s working on a test to detect the disease in its early stages.

“The beauty of urine is that it is abundant, and nobody really wants it other than people like me. It’s very helpful when patients give permission for us to use their urine for research.”

Bladder cancer is perhaps the most obvious cancer to find in urine, but evidence suggests that remnants of other cancers – like kidney, prostate and cervical cancer – can also get into pee.

How do cancer clues get into urine?

There are two main ways for cancer to end up urine – through the kidneys or from the bladder and ureters (the tubes that connect the kidneys to the bladder).

Molecules released by cancer cells can travel to the kidneys via the blood. But to pass through the kidney’s delicate filtering system and enter the bladder, these molecules need to be small. They’re usually molecular building blocks that make up cancer cells, like proteins.

And a useful clue doesn’t have to come from the cancer directly. There are promising studies that show that the human papillomavirus (HPV), a virus responsible for the majority of cervical cancer cases, can be detected in the urine.

Larger clues – like entire cancer cells or their DNA – are too big to pass through the kidneys and will have to come from the bladder or ureters. Pee contains normal bladder cells that have dropped off from the lining of the urinary tract as part of the normal cell lifecycle. “If you have disease, diseased cells will be there too,” says Bryan, whose research is looking for the DNA of bladder cancer cells in urine.

Looking for bladder cancer in pee

We’ve discussed before that a successful cancer test needs to tick certain boxes.

Bryan says there’s already an effective way to pick up bladder cancer in people who have symptoms, called cystoscopy, where a flexible camera is inserted into the urethra.

“Whether that is acceptable to use as a screening a test, is open to debate,” says Bryan adding that even though the unpleasant procedure is reliable it’s also expensive, labour-intensive and sometimes requires patients to be put to sleep to receive it.

At the moment the biggest ‘reg flag’ that a person might have bladder cancer is blood in their urine. It’s a symptom that usually puts a person in line for cystoscopy.

“But only around a fifth of people with blood in their urine will actually have bladder cancer, so we’re hoping to develop a urine test that will help narrow this down.” Then those given the cystoscopy would be the ones most likely to need it.

To make this test, Bryan and his team are trying to pin down the DNA fragments from bladder cancer cells that appear in the urine, which would flag up those who need further tests.

“The aim then would be to take those with a positive urine test into the operating theatre to have a cystoscopy and treat them for the cancer right there and then, as soon as we see it.”

The team have tested 800 urine samples for these DNA fragments. “We have a very promising experimental test that identifies the most common genetic changes seen in bladder cancer.”

Now they’re starting to look at whether they’ve managed to pick up cancer using these clues. And if they do find the test can detect cancer, it will then need to be validated in large clinical trials.

Bryan also says the test is not intended to screen the entire population as at the moment it wouldn’t be cost-effective to give the test to everyone. But as well as those who are worried about blood in their urine, the test is likely to be useful to those who are at higher risk of bladder cancer. “This could be people who have smoked for a long time or who have worked with certain industrial chemicals for prolonged periods,” he says.

A urine test to detect signs of bladder cancer could mean a swift and less invasive tool to decide if someone needs more tests. But where urine tests really have the power to transform the future for patients is pancreatic cancer.

Testing pee for pancreatic cancer

At the moment there’s no easy way to diagnose pancreatic cancer at an early stage. A diagnosis usually involves a series of scans and invasive biopsies that are normally done once a person has developed symptoms. But by the time they show signs of illness, the disease is usually too advanced to be treated successfully.

A group of our scientists in London want to change this.

“We started like everybody else,” says Professor Tatjana Crnogorac-Jurcevic from Queen Mary, University of London, “and began looking in the blood for pancreatic cancer.” Her team soon realised blood was teeming with molecules released from all kinds of other cells.

Urine is a lot less crowded. Crnogorac-Jurcevic says around 40% of material found in urine is from outside the kidneys and urinary tract. “The blood plasma is filtered through the kidneys, so you can detect lots of things in it.”

After 15 years of hard work, Crnogorac-Jurcevic and her team have found 3 key proteins linked to pancreatic cancer that successfully flag up its presence in pee.

She says that people often use the analogy for early detection as ‘looking for a needle in a haystack’. “We’ve already gone through the haystack and found our needles, so now it’s really a matter of evaluating our test on large samples of patients.”

Excitingly, the clinical trial testing this pancreatic cancer-detecting tool is about to start recruiting patients.

“We’re hoping that by the time we have the results of our clinical study we’ll be ready to offer this test to patients,” says Crnogorac-Jurcevic. Pancreatic cancer also isn’t very common, so once a test is ready to go it will mostly likely be used on those who are known to have a higher risk of developing the disease, like people with certain genes.

It might be a few years until needles are a thing of the past when detecting the early stages of certain cancer types, but there’s no doubt of the impact a urine test could have on a patient’s wellbeing and how well they do.

Crnogorac-Jurcevic says it was extremely difficult for researchers looking at urine to get projects going at first because, “no one really thought you could find cancer markers in urine.” But the perseverance is paying off, “I’m constantly looking ahead and I’m very pleased with where we are at the moment.”

Gabi

Follow our early detection series to find out all the other ways – and bodily fluids – our scientists are looking for cancer in to detect it earlier and boost the chance of people surviving the disease.

 

from Cancer Research UK – Science blog https://ift.tt/2O58NRE

Feeling anxious around needles is common. The NHS estimates that around 1 in 10 people experience trypanophobia, a fear of medical procedures that involve needles or injections.

Unfortunately, in medicine, the use of needles is often necessary to check on a person’s health. But looking in the blood may not be the only way to find clues left behind by disease. Other bodily fluids, like urine, also have the potential to reveal what’s going on in our bodies.

“Urine gives a great insight into what’s going on inside our bodies,” says Mr Richard Bryan from the University of Birmingham, a Cancer Research UK-funded bladder cancer surgeon who’s working on a test to detect the disease in its early stages.

“The beauty of urine is that it is abundant, and nobody really wants it other than people like me. It’s very helpful when patients give permission for us to use their urine for research.”

Bladder cancer is perhaps the most obvious cancer to find in urine, but evidence suggests that remnants of other cancers – like kidney, prostate and cervical cancer – can also get into pee.

How do cancer clues get into urine?

There are two main ways for cancer to end up urine – through the kidneys or from the bladder and ureters (the tubes that connect the kidneys to the bladder).

Molecules released by cancer cells can travel to the kidneys via the blood. But to pass through the kidney’s delicate filtering system and enter the bladder, these molecules need to be small. They’re usually molecular building blocks that make up cancer cells, like proteins.

And a useful clue doesn’t have to come from the cancer directly. There are promising studies that show that the human papillomavirus (HPV), a virus responsible for the majority of cervical cancer cases, can be detected in the urine.

Larger clues – like entire cancer cells or their DNA – are too big to pass through the kidneys and will have to come from the bladder or ureters. Pee contains normal bladder cells that have dropped off from the lining of the urinary tract as part of the normal cell lifecycle. “If you have disease, diseased cells will be there too,” says Bryan, whose research is looking for the DNA of bladder cancer cells in urine.

Looking for bladder cancer in pee

We’ve discussed before that a successful cancer test needs to tick certain boxes.

Bryan says there’s already an effective way to pick up bladder cancer in people who have symptoms, called cystoscopy, where a flexible camera is inserted into the urethra.

“Whether that is acceptable to use as a screening a test, is open to debate,” says Bryan adding that even though the unpleasant procedure is reliable it’s also expensive, labour-intensive and sometimes requires patients to be put to sleep to receive it.

At the moment the biggest ‘reg flag’ that a person might have bladder cancer is blood in their urine. It’s a symptom that usually puts a person in line for cystoscopy.

“But only around a fifth of people with blood in their urine will actually have bladder cancer, so we’re hoping to develop a urine test that will help narrow this down.” Then those given the cystoscopy would be the ones most likely to need it.

To make this test, Bryan and his team are trying to pin down the DNA fragments from bladder cancer cells that appear in the urine, which would flag up those who need further tests.

“The aim then would be to take those with a positive urine test into the operating theatre to have a cystoscopy and treat them for the cancer right there and then, as soon as we see it.”

The team have tested 800 urine samples for these DNA fragments. “We have a very promising experimental test that identifies the most common genetic changes seen in bladder cancer.”

Now they’re starting to look at whether they’ve managed to pick up cancer using these clues. And if they do find the test can detect cancer, it will then need to be validated in large clinical trials.

Bryan also says the test is not intended to screen the entire population as at the moment it wouldn’t be cost-effective to give the test to everyone. But as well as those who are worried about blood in their urine, the test is likely to be useful to those who are at higher risk of bladder cancer. “This could be people who have smoked for a long time or who have worked with certain industrial chemicals for prolonged periods,” he says.

A urine test to detect signs of bladder cancer could mean a swift and less invasive tool to decide if someone needs more tests. But where urine tests really have the power to transform the future for patients is pancreatic cancer.

Testing pee for pancreatic cancer

At the moment there’s no easy way to diagnose pancreatic cancer at an early stage. A diagnosis usually involves a series of scans and invasive biopsies that are normally done once a person has developed symptoms. But by the time they show signs of illness, the disease is usually too advanced to be treated successfully.

A group of our scientists in London want to change this.

“We started like everybody else,” says Professor Tatjana Crnogorac-Jurcevic from Queen Mary, University of London, “and began looking in the blood for pancreatic cancer.” Her team soon realised blood was teeming with molecules released from all kinds of other cells.

Urine is a lot less crowded. Crnogorac-Jurcevic says around 40% of material found in urine is from outside the kidneys and urinary tract. “The blood plasma is filtered through the kidneys, so you can detect lots of things in it.”

After 15 years of hard work, Crnogorac-Jurcevic and her team have found 3 key proteins linked to pancreatic cancer that successfully flag up its presence in pee.

She says that people often use the analogy for early detection as ‘looking for a needle in a haystack’. “We’ve already gone through the haystack and found our needles, so now it’s really a matter of evaluating our test on large samples of patients.”

Excitingly, the clinical trial testing this pancreatic cancer-detecting tool is about to start recruiting patients.

“We’re hoping that by the time we have the results of our clinical study we’ll be ready to offer this test to patients,” says Crnogorac-Jurcevic. Pancreatic cancer also isn’t very common, so once a test is ready to go it will mostly likely be used on those who are known to have a higher risk of developing the disease, like people with certain genes.

It might be a few years until needles are a thing of the past when detecting the early stages of certain cancer types, but there’s no doubt of the impact a urine test could have on a patient’s wellbeing and how well they do.

Crnogorac-Jurcevic says it was extremely difficult for researchers looking at urine to get projects going at first because, “no one really thought you could find cancer markers in urine.” But the perseverance is paying off, “I’m constantly looking ahead and I’m very pleased with where we are at the moment.”

Gabi

Follow our early detection series to find out all the other ways – and bodily fluids – our scientists are looking for cancer in to detect it earlier and boost the chance of people surviving the disease.

 

from Cancer Research UK – Science blog https://ift.tt/2O58NRE

Venus and Jupiter getting closer!

Read more: Venus/Jupiter conjunction on November 24

View at EarthSky Community Photos. | Peter Lowenstein in Mutare, Zimbabwe captured this image on November 18, 2019. He wrote: “A break in the weather after the onset of the rains provided a good Southern Hemisphere view of Jupiter (above) and bright Venus (below) getting closer together in the twilight sky. Antares is also faintly visible (lower left).” Thank you, Peter!

View at EarthSky Community Photos. | Carl Keene also caught the planets on November 18, from San Jose, California. There’s a 3rd planet in this photo, too, Saturn, in the upper left. Thank you, Carl!

Bottom line: Photos from the EarthSky Community of the very bright planets Jupiter and Venus, now in the west after sunset. Watch for them!

from EarthSky https://ift.tt/2r7mQNs

Read more: Venus/Jupiter conjunction on November 24

View at EarthSky Community Photos. | Peter Lowenstein in Mutare, Zimbabwe captured this image on November 18, 2019. He wrote: “A break in the weather after the onset of the rains provided a good Southern Hemisphere view of Jupiter (above) and bright Venus (below) getting closer together in the twilight sky. Antares is also faintly visible (lower left).” Thank you, Peter!

View at EarthSky Community Photos. | Carl Keene also caught the planets on November 18, from San Jose, California. There’s a 3rd planet in this photo, too, Saturn, in the upper left. Thank you, Carl!

Bottom line: Photos from the EarthSky Community of the very bright planets Jupiter and Venus, now in the west after sunset. Watch for them!

from EarthSky https://ift.tt/2r7mQNs

New global geologic map of Titan, Saturn’s largest moon

View larger. | Labels point to several of Titan’s named surface features. The legend colors represent the broad types of geologic units found on Titan: plains (broad, relatively flat regions), labyrinth (tectonically disrupted regions often containing fluvial channels), hummocky (hilly, with some mountains), dunes (mostly linear dunes, produced by winds in Titan’s atmosphere), craters (formed by impacts) and lakes (regions now or previously filled with liquid methane or ethane). Titan is the only planetary body in our solar system other than Earth known to have stable liquid on its surface — methane and ethane. Image via NASA/JPL-Caltech/ASU.

Scientists have completed the first map showing the global geology of Saturn’s largest moon, Titan. The new map reveals a dynamic world of dunes, lakes, plains, craters and other terrains.

The map is based on radar and visible-light images from NASA’s Cassini mission, which orbited Saturn from 2004 to 2017.

Titan is the largest of planet Saturn’s 82 moons. Titan is the only planetary body in our solar system – other than Earth – known to have stable liquid on its surface. But on Titan the liquid that rains down from the clouds and fills lakes and seas isn’t water. It’s methane and ethane – hydrocarbons that we think of as gases but that behave as liquids on the frigid world of Titan.

NASA planetary geologist Rosaly Lopes is lead author of new research used to develop the map, published Monday (November 18, 2019) in the journal Nature Astronomy. Lopes said in a statement:

Titan has an active methane-based hydrologic cycle that has shaped a complex geologic landscape, making its surface one of most geologically diverse in the solar system.

Despite the different materials, temperatures and gravity fields between Earth and Titan, many surface features are similar between the two worlds and can be interpreted as being products of the same geologic processes. The map shows that the different geologic terrains have a clear distribution with latitude, globally, and that some terrains cover far more area than others.

EarthSky lunar calendars make great gifts for astronomy-minded friends and family. Order now. Going fast!

The colorful globe of Saturn’s largest moon, Titan, passes in front of the planet and its rings in this true color snapshot from NASA’s Cassini spacecraft. Image via NASA.

The researchers used data from the radar imager on the Cassini spacecraft, which did more than 120 flybys of Titan between 2004 and 2017. Lopes said:

This study is an example of using combined datasets and instruments. Although we did not have global coverage with synthetic aperture radar [SAR], we used data from other instruments and other modes from radar to correlate characteristics of the different terrain units so we could infer what the terrains are even in areas where we don’t have SAR coverage.

Planetary geologist David Williams of Arizona State University is a study co-author. He said:

The Cassini mission revealed that Titan is a geologically active world, where hydrocarbons like methane and ethane take the role that water has on Earth. These hydrocarbons rain down on the surface, flow in streams and rivers, accumulate in lakes and seas, and evaporate into the atmosphere. It’s quite an astounding world!

Bottom line: Map showing the global geology of Saturn’s largest moon Titan.

Source: A global geomorphologic map of Saturn’s moon Titan

Via NASA

from EarthSky https://ift.tt/2D2Ubvy

View larger. | Labels point to several of Titan’s named surface features. The legend colors represent the broad types of geologic units found on Titan: plains (broad, relatively flat regions), labyrinth (tectonically disrupted regions often containing fluvial channels), hummocky (hilly, with some mountains), dunes (mostly linear dunes, produced by winds in Titan’s atmosphere), craters (formed by impacts) and lakes (regions now or previously filled with liquid methane or ethane). Titan is the only planetary body in our solar system other than Earth known to have stable liquid on its surface — methane and ethane. Image via NASA/JPL-Caltech/ASU.

Scientists have completed the first map showing the global geology of Saturn’s largest moon, Titan. The new map reveals a dynamic world of dunes, lakes, plains, craters and other terrains.

The map is based on radar and visible-light images from NASA’s Cassini mission, which orbited Saturn from 2004 to 2017.

Titan is the largest of planet Saturn’s 82 moons. Titan is the only planetary body in our solar system – other than Earth – known to have stable liquid on its surface. But on Titan the liquid that rains down from the clouds and fills lakes and seas isn’t water. It’s methane and ethane – hydrocarbons that we think of as gases but that behave as liquids on the frigid world of Titan.

NASA planetary geologist Rosaly Lopes is lead author of new research used to develop the map, published Monday (November 18, 2019) in the journal Nature Astronomy. Lopes said in a statement:

Titan has an active methane-based hydrologic cycle that has shaped a complex geologic landscape, making its surface one of most geologically diverse in the solar system.

Despite the different materials, temperatures and gravity fields between Earth and Titan, many surface features are similar between the two worlds and can be interpreted as being products of the same geologic processes. The map shows that the different geologic terrains have a clear distribution with latitude, globally, and that some terrains cover far more area than others.

EarthSky lunar calendars make great gifts for astronomy-minded friends and family. Order now. Going fast!

The colorful globe of Saturn’s largest moon, Titan, passes in front of the planet and its rings in this true color snapshot from NASA’s Cassini spacecraft. Image via NASA.

The researchers used data from the radar imager on the Cassini spacecraft, which did more than 120 flybys of Titan between 2004 and 2017. Lopes said:

This study is an example of using combined datasets and instruments. Although we did not have global coverage with synthetic aperture radar [SAR], we used data from other instruments and other modes from radar to correlate characteristics of the different terrain units so we could infer what the terrains are even in areas where we don’t have SAR coverage.

Planetary geologist David Williams of Arizona State University is a study co-author. He said:

The Cassini mission revealed that Titan is a geologically active world, where hydrocarbons like methane and ethane take the role that water has on Earth. These hydrocarbons rain down on the surface, flow in streams and rivers, accumulate in lakes and seas, and evaporate into the atmosphere. It’s quite an astounding world!

Bottom line: Map showing the global geology of Saturn’s largest moon Titan.

Source: A global geomorphologic map of Saturn’s moon Titan

Via NASA

from EarthSky https://ift.tt/2D2Ubvy

Listen to Earth’s magnetic song

An international team of scientists, using data from ESA’s Cluster mission, have created the first recording of the eerie “song” that Earth makes when it’s hit by a solar storm.

The song comes from waves that are generated in the Earth’s magnetic field by the collision of the storm. The storm itself is the eruption of electrically charged particles from the sun’s atmosphere. The sun constantly sends out streams of charged particles, but Earth’s magnetic field prevents these particles from entering our atmosphere. However, explosions on the sun’s surface can send a huge clouds of particles and radiation out into space. If these solar storms are directed towards Earth, when they hit they can disrupt our satellite systems, cause widespread blackouts and affect GPS systems.

To create the recording, the team analyzed two decades of data from ESA’s Cluster mission, four spacecraft that have been orbiting Earth in formation since 2001, investigating our planet’s magnetic environment and its interaction with the solar wind.

As part of their orbits, the Cluster spacecraft repeatedly fly through the what’s called the foreshock, the first region that particles encounter when a solar storm hits our planet. The team found that in the early part of the mission, from 2001 to 2005, the spacecraft flew through six such collisions, recording the waves that were generated.

The new analysis shows that, during the collision, the foreshock releases magnetic waves that are much more complex than first thought.

When the frequencies of these magnetic waves are transformed into audible signals, they give rise to a psychedelic song more reminiscent of sound effects from a science fiction movie than from a natural phenomenon.

EarthSky lunar calendars make great gifts for astronomy-minded friends and family. Order now. Going fast!

In this image, Earth is the dot to the left of the image and the large arc around it is our planet’s magnetic bow shock. The swirling pattern to the right is the foreshock region where the solar wind breaks into waves as it encounters reflected particles from the bow shock. The image was created using the Vlasiator model, a computer simulation developed at the University of Helsinki to study Earth’s magnetic interaction with the solar wind. Image via Vlasiator team, University of Helsinki.

In quiet times, when no solar storm is striking the Earth, the song is lower in pitch and less complex. But when a solar storm hits, the frequency of the wave is roughly doubled, depending on the strength of the magnetic field in the storm.

University of Helsinki astrophysicist Lucile Turc is lead author of the study, published November 18, 2019 in the peer-reviewed journal Geophysical Research Letters. She said in a statement:

It’s like the storm is changing the tuning of the foreshock.

The researchers said that not only does the frequency of the wave change, but it also becomes much more complicated than the single frequency of the quiet times. Once the storm hits the foreshock, the wave breaks into a complex network of different, higher frequencies. According to a statement about the research:

The changes in the foreshock have the power to affect the way the solar storm is propagated down to the Earth’s surface. Although it is still an open question exactly how this process works, it is clear that the energy generated by waves in the foreshock cannot escape back into space, as the waves are pushed towards Earth by the incoming solar storm.

Before they reach our atmosphere, however, the waves encounter another barrier, called the bow shock, which is the magnetic region of space that slows down solar wind particles before they collide with Earth’s magnetic field. The collision of the magnetic waves modifies the behavior of the bow shock, possibly changing the way it processes the energy of the incoming solar storm.

Behind the bow shock, the magnetic fields of Earth start to resonate at the frequency of the waves and this contributes to the transmission of the magnetic disturbance all the way to the ground. It is a fast process, taking around 10 minutes from the wave being generated at the foreshock to its energy reaching the ground.

Bottom line: Listen to an eerie song of Earth getting hit by a magnetic storm.

Source: First Observations of the Disruption of the Earth’s Foreshock Wave Field During Magnetic Clouds

Via AGU

from EarthSky https://ift.tt/2Xxju2r

An international team of scientists, using data from ESA’s Cluster mission, have created the first recording of the eerie “song” that Earth makes when it’s hit by a solar storm.

The song comes from waves that are generated in the Earth’s magnetic field by the collision of the storm. The storm itself is the eruption of electrically charged particles from the sun’s atmosphere. The sun constantly sends out streams of charged particles, but Earth’s magnetic field prevents these particles from entering our atmosphere. However, explosions on the sun’s surface can send a huge clouds of particles and radiation out into space. If these solar storms are directed towards Earth, when they hit they can disrupt our satellite systems, cause widespread blackouts and affect GPS systems.

To create the recording, the team analyzed two decades of data from ESA’s Cluster mission, four spacecraft that have been orbiting Earth in formation since 2001, investigating our planet’s magnetic environment and its interaction with the solar wind.

As part of their orbits, the Cluster spacecraft repeatedly fly through the what’s called the foreshock, the first region that particles encounter when a solar storm hits our planet. The team found that in the early part of the mission, from 2001 to 2005, the spacecraft flew through six such collisions, recording the waves that were generated.

The new analysis shows that, during the collision, the foreshock releases magnetic waves that are much more complex than first thought.

When the frequencies of these magnetic waves are transformed into audible signals, they give rise to a psychedelic song more reminiscent of sound effects from a science fiction movie than from a natural phenomenon.

EarthSky lunar calendars make great gifts for astronomy-minded friends and family. Order now. Going fast!

In this image, Earth is the dot to the left of the image and the large arc around it is our planet’s magnetic bow shock. The swirling pattern to the right is the foreshock region where the solar wind breaks into waves as it encounters reflected particles from the bow shock. The image was created using the Vlasiator model, a computer simulation developed at the University of Helsinki to study Earth’s magnetic interaction with the solar wind. Image via Vlasiator team, University of Helsinki.

In quiet times, when no solar storm is striking the Earth, the song is lower in pitch and less complex. But when a solar storm hits, the frequency of the wave is roughly doubled, depending on the strength of the magnetic field in the storm.

University of Helsinki astrophysicist Lucile Turc is lead author of the study, published November 18, 2019 in the peer-reviewed journal Geophysical Research Letters. She said in a statement:

It’s like the storm is changing the tuning of the foreshock.

The researchers said that not only does the frequency of the wave change, but it also becomes much more complicated than the single frequency of the quiet times. Once the storm hits the foreshock, the wave breaks into a complex network of different, higher frequencies. According to a statement about the research:

The changes in the foreshock have the power to affect the way the solar storm is propagated down to the Earth’s surface. Although it is still an open question exactly how this process works, it is clear that the energy generated by waves in the foreshock cannot escape back into space, as the waves are pushed towards Earth by the incoming solar storm.

Before they reach our atmosphere, however, the waves encounter another barrier, called the bow shock, which is the magnetic region of space that slows down solar wind particles before they collide with Earth’s magnetic field. The collision of the magnetic waves modifies the behavior of the bow shock, possibly changing the way it processes the energy of the incoming solar storm.

Behind the bow shock, the magnetic fields of Earth start to resonate at the frequency of the waves and this contributes to the transmission of the magnetic disturbance all the way to the ground. It is a fast process, taking around 10 minutes from the wave being generated at the foreshock to its energy reaching the ground.

Bottom line: Listen to an eerie song of Earth getting hit by a magnetic storm.

Source: First Observations of the Disruption of the Earth’s Foreshock Wave Field During Magnetic Clouds

Via AGU

from EarthSky https://ift.tt/2Xxju2r

Use Big Dipper to find star Capella

Tonight – or any autumn or winter evening – if you can see the Big Dipper, use its famous pointer stars (which point to Polaris, the North Star) to find the bright golden star Capella in the constellation Auriga the Charioteer. The top two bowl stars point toward Capella, as we depict on the chart at the top of this post.

Capella is sometimes called the Goat Star. In fact, the star name Capella is the Latin word for nanny goat. Near Capella, you’ll find a tiny asterism – a noticeable pattern on the sky’s dome – consisting of three fainter stars. This little triangle of stars is called the Kids (baby goats).

The 2019 lunar calendars are here! Order yours before they’re gone. Makes a great gift.

The phrase spring up and fall down gives you some idea of the Big Dipper’s place in the evening sky. On fall evenings for us in the Northern Hemisphere, the Big Dipper sits way down low in the northern sky.

On northern spring evenings, the Big Dipper shines high above Polaris, the North Star.

From the Southern Hemisphere: Sorry, y’all. These are northern stars and not easily visible to you … unless you come visit our part of the world!

From the far southern U.S. and similar latitudes: You won’t see the Big Dipper on these November evenings, either. From more southerly latitudes in the Northern Hemisphere, the Big Dipper is below your northern horizon on autumn evenings. Even in the northern states, it’ll be possible to miss the Big Dipper if obstructions block your view of the northern sky. However, the Big Dipper swings full circle around Polaris, the North Star, once a day. Thus, from these latitudes, the Big Dipper will appear fairly high in the northeast sky before morning dawn in November.

It’s a long jump from the Big Dipper bowl stars to Capella. Our chart at top goes all the way from northwest to northeast. That’s about one-fourth the way around the horizon.

And remember, the Big Dipper and Capella move throughout the night, and throughout the year, but – no matter when and where you see them – they are part of the “fixed” star background … and so always maintain this relationship to one another.

The bright star Capella and its constellation Auriga the Charioteer as seen in the east-northeast sky. Image via Wikimedia Commons.

Bottom line: You’ve heard of the “pointer” stars of the Big Dipper? They point to the North Star. You can also use them to find the star Capella, aka the Goat Star.

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Enjoying EarthSky so far? Sign up for our free daily newsletter today!

Easily locate stars and constellations during any day and time with EarthSky’s Planisphere.

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

Tonight – or any autumn or winter evening – if you can see the Big Dipper, use its famous pointer stars (which point to Polaris, the North Star) to find the bright golden star Capella in the constellation Auriga the Charioteer. The top two bowl stars point toward Capella, as we depict on the chart at the top of this post.

Capella is sometimes called the Goat Star. In fact, the star name Capella is the Latin word for nanny goat. Near Capella, you’ll find a tiny asterism – a noticeable pattern on the sky’s dome – consisting of three fainter stars. This little triangle of stars is called the Kids (baby goats).

The 2019 lunar calendars are here! Order yours before they’re gone. Makes a great gift.

The phrase spring up and fall down gives you some idea of the Big Dipper’s place in the evening sky. On fall evenings for us in the Northern Hemisphere, the Big Dipper sits way down low in the northern sky.

On northern spring evenings, the Big Dipper shines high above Polaris, the North Star.

From the Southern Hemisphere: Sorry, y’all. These are northern stars and not easily visible to you … unless you come visit our part of the world!

From the far southern U.S. and similar latitudes: You won’t see the Big Dipper on these November evenings, either. From more southerly latitudes in the Northern Hemisphere, the Big Dipper is below your northern horizon on autumn evenings. Even in the northern states, it’ll be possible to miss the Big Dipper if obstructions block your view of the northern sky. However, the Big Dipper swings full circle around Polaris, the North Star, once a day. Thus, from these latitudes, the Big Dipper will appear fairly high in the northeast sky before morning dawn in November.

It’s a long jump from the Big Dipper bowl stars to Capella. Our chart at top goes all the way from northwest to northeast. That’s about one-fourth the way around the horizon.

And remember, the Big Dipper and Capella move throughout the night, and throughout the year, but – no matter when and where you see them – they are part of the “fixed” star background … and so always maintain this relationship to one another.

The bright star Capella and its constellation Auriga the Charioteer as seen in the east-northeast sky. Image via Wikimedia Commons.

Bottom line: You’ve heard of the “pointer” stars of the Big Dipper? They point to the North Star. You can also use them to find the star Capella, aka the Goat Star.

Donate: Your support means the world to us

Enjoying EarthSky so far? Sign up for our free daily newsletter today!

Easily locate stars and constellations during any day and time with EarthSky’s Planisphere.

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

ESA studies human hibernation for space travel

Fictional image of hibernating astronauts, via ESA.

The European Space Agency (ESA) said on November 18, 2019, that its scientists have recently been investigating the process of placing astronauts into hibernation to cross the vastness of space. These scientists met at ESA’s Concurrent Design Facility to assess the advantages of human hibernation for a trip to a neighboring planet, such as Mars. They took as their reference an existing study that described sending six humans to Mars and back on a five-year timescale. They studied how crew hibernation would impact space mission design, and put some numbers to known advantages to human hibernation for space travel, for example, that a smaller space capsule could be used if the crew were hibernating, rather than awake, for the months-long journey to Mars.

Jennifer Ngo-Anh, a team leader in ESA’s Science in Space Environment (SciSpacE) program, commented:

For a while now hibernation has been proposed as a game-changing tool for human space travel.

If we were able to reduce an astronaut’s basic metabolic rate by 75% – similar to what we can observe in nature with large hibernating animals such as certain bears – we could end up with substantial mass and cost savings, making long-duration exploration missions more feasible.

EarthSky 2020 lunar calendars are available! They make great gifts. Order now. Going fast!

Here is ESA’s Concurrent Design Facility, which hosts representatives of all space mission disciplines in order to design future space missions. Image via ESA.

Why do we need to put astronauts into hibernation at all? The reason is that space is vast. Even our own neighborhood of space – our solar system – is subject to a space-is-vast issue that factors heavily into our missions to explore the other planets near us in space. Consider that the New Horizons mission to Pluto, for example – launched in 2006 – needed nine years to get to its flyby.

To get an idea of the distance scale of our solar system, visit “If the moon were only 1 pixel” showing the relative distances of the planets to scale on a single extra-wide page. Then try – if you can – to extend what you’ve learned to the billions of other likely solar systems in our galaxy alone.

As Joe Hansen – host of the PBS series “It’s Okay to be Smart” – says in the video below:

The human brain just can’t fathom how big things like the solar system are.

Robin Biesbroek of ESA – who has worked in the past on the removal of space debris from low-Earth orbit – was part of the recent ESA study on human hibernation. He commented:

We worked on adjusting the architecture of the spacecraft, its logistics, protection against radiation, power consumption and overall mission design.

We looked at how an astronaut team could be best put into hibernation, what to do in case of emergencies, how to handle human safety and even what impact hibernation would have on the psychology of the team.

Finally we created an initial sketch of the habitat architecture and created a roadmap to achieve a validated approach to hibernate humans to Mars within 20 years.

The scientists found that the mass of a spacecraft for human hibernation could be reduced by a third.

The ESA scientists quantified what might seem fairly obvious … that a spacecraft for hibernating astronauts could be on the small side. This comparison shows the size of a module for a crewed Mars mission with its hibernation-based equivalent. Image via ESA.

If the crew were hibernating, you wouldn’t need extensive crew quarters, or as much storage room for consumables (like food and water). Hibernation module design via ESA.

ESA said hibernation would take place in small individual pods that would double as cabins while the crew are awake. Hibernation pod design via ESA.

What would it be like for the astronauts? ESA explained:

The assumption was that a drug would be administered to induce ‘torpor’ – the term for the hibernating state. Like hibernating animals, the astronauts would be expected to acquire extra body fat in advance of torpor. Their soft-shell pods would be darkened and their temperature greatly reduced to cool their occupants during their projected 180-day Earth-Mars cruise.

ESA said the hibernating cruise phase would end with a 21-day recuperation period. It said that – based on the experience of animal hibernation – the crew would likely not experience bone or muscle wastage. ESA also explained:

Radiation exposure from high-energy particles is a key hazard of deep space travel, but because the hibernating crew will be spending so much time in their hibernation pods, then shielding – such as water containers – could be concentrated around them.

And ESA also spoke of the “largely autonomous operations, with optimum use of artificial intelligence” and “fault detection, isolation and recovery” needed on a spaceship where most humans are hibernating.

Sound a bit creepy or lonely? Maybe. But Ngo-Anh commented:

… the basic idea of putting astronauts into long-duration hibernation is actually not so crazy: a broadly comparable method has been tested and applied as therapy in critical care trauma patients and those due to undergo major surgeries for more than two decades. Most major medical centres have protocols for inducing hypothermia in patients to reduce their metabolism to basically gain time, keeping patients in a better shape than they otherwise would be.

We aim to build on this in future, by researching the brain pathways that are activated or blocked during initiation of hibernation, starting with animals and proceeding to people.

NASA has contracted studies on human hibernation in space, too. This image is a “settlement-class Mars Transfer Habitat” designed by NASA contractor SpaceWorks in 2017. Read more: Sleeping their way to Mars.

By the way, if you’re interested in reading a wonderful recent science fiction series depicting deep-space travel via human hibernation – two of the best sci-fi books I’ve ever read (and I’ve read a bunch) – try “Children of Time” and “Children of Ruin” by Adrian Tchaikovksy. Both have all the things I love in science fiction: travel over millenia among the stars, how the hibernating travelers perceive time passing, strange planets, weird aliens, a human love story. Human hibernation plays a big role in these awesome books!

The cover of “Children of Time” by Adrian Tchaikovksy.

Bottom line: The European Space Agency has been studying how real-life human hibernation would impact space mission design.

Via ESA

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

Fictional image of hibernating astronauts, via ESA.

The European Space Agency (ESA) said on November 18, 2019, that its scientists have recently been investigating the process of placing astronauts into hibernation to cross the vastness of space. These scientists met at ESA’s Concurrent Design Facility to assess the advantages of human hibernation for a trip to a neighboring planet, such as Mars. They took as their reference an existing study that described sending six humans to Mars and back on a five-year timescale. They studied how crew hibernation would impact space mission design, and put some numbers to known advantages to human hibernation for space travel, for example, that a smaller space capsule could be used if the crew were hibernating, rather than awake, for the months-long journey to Mars.

Jennifer Ngo-Anh, a team leader in ESA’s Science in Space Environment (SciSpacE) program, commented:

For a while now hibernation has been proposed as a game-changing tool for human space travel.

If we were able to reduce an astronaut’s basic metabolic rate by 75% – similar to what we can observe in nature with large hibernating animals such as certain bears – we could end up with substantial mass and cost savings, making long-duration exploration missions more feasible.

EarthSky 2020 lunar calendars are available! They make great gifts. Order now. Going fast!

Here is ESA’s Concurrent Design Facility, which hosts representatives of all space mission disciplines in order to design future space missions. Image via ESA.

Why do we need to put astronauts into hibernation at all? The reason is that space is vast. Even our own neighborhood of space – our solar system – is subject to a space-is-vast issue that factors heavily into our missions to explore the other planets near us in space. Consider that the New Horizons mission to Pluto, for example – launched in 2006 – needed nine years to get to its flyby.

To get an idea of the distance scale of our solar system, visit “If the moon were only 1 pixel” showing the relative distances of the planets to scale on a single extra-wide page. Then try – if you can – to extend what you’ve learned to the billions of other likely solar systems in our galaxy alone.

As Joe Hansen – host of the PBS series “It’s Okay to be Smart” – says in the video below:

The human brain just can’t fathom how big things like the solar system are.

Robin Biesbroek of ESA – who has worked in the past on the removal of space debris from low-Earth orbit – was part of the recent ESA study on human hibernation. He commented:

We worked on adjusting the architecture of the spacecraft, its logistics, protection against radiation, power consumption and overall mission design.

We looked at how an astronaut team could be best put into hibernation, what to do in case of emergencies, how to handle human safety and even what impact hibernation would have on the psychology of the team.

Finally we created an initial sketch of the habitat architecture and created a roadmap to achieve a validated approach to hibernate humans to Mars within 20 years.

The scientists found that the mass of a spacecraft for human hibernation could be reduced by a third.

The ESA scientists quantified what might seem fairly obvious … that a spacecraft for hibernating astronauts could be on the small side. This comparison shows the size of a module for a crewed Mars mission with its hibernation-based equivalent. Image via ESA.

If the crew were hibernating, you wouldn’t need extensive crew quarters, or as much storage room for consumables (like food and water). Hibernation module design via ESA.

ESA said hibernation would take place in small individual pods that would double as cabins while the crew are awake. Hibernation pod design via ESA.

What would it be like for the astronauts? ESA explained:

The assumption was that a drug would be administered to induce ‘torpor’ – the term for the hibernating state. Like hibernating animals, the astronauts would be expected to acquire extra body fat in advance of torpor. Their soft-shell pods would be darkened and their temperature greatly reduced to cool their occupants during their projected 180-day Earth-Mars cruise.

ESA said the hibernating cruise phase would end with a 21-day recuperation period. It said that – based on the experience of animal hibernation – the crew would likely not experience bone or muscle wastage. ESA also explained:

Radiation exposure from high-energy particles is a key hazard of deep space travel, but because the hibernating crew will be spending so much time in their hibernation pods, then shielding – such as water containers – could be concentrated around them.

And ESA also spoke of the “largely autonomous operations, with optimum use of artificial intelligence” and “fault detection, isolation and recovery” needed on a spaceship where most humans are hibernating.

Sound a bit creepy or lonely? Maybe. But Ngo-Anh commented:

… the basic idea of putting astronauts into long-duration hibernation is actually not so crazy: a broadly comparable method has been tested and applied as therapy in critical care trauma patients and those due to undergo major surgeries for more than two decades. Most major medical centres have protocols for inducing hypothermia in patients to reduce their metabolism to basically gain time, keeping patients in a better shape than they otherwise would be.

We aim to build on this in future, by researching the brain pathways that are activated or blocked during initiation of hibernation, starting with animals and proceeding to people.

NASA has contracted studies on human hibernation in space, too. This image is a “settlement-class Mars Transfer Habitat” designed by NASA contractor SpaceWorks in 2017. Read more: Sleeping their way to Mars.

By the way, if you’re interested in reading a wonderful recent science fiction series depicting deep-space travel via human hibernation – two of the best sci-fi books I’ve ever read (and I’ve read a bunch) – try “Children of Time” and “Children of Ruin” by Adrian Tchaikovksy. Both have all the things I love in science fiction: travel over millenia among the stars, how the hibernating travelers perceive time passing, strange planets, weird aliens, a human love story. Human hibernation plays a big role in these awesome books!

The cover of “Children of Time” by Adrian Tchaikovksy.

Bottom line: The European Space Agency has been studying how real-life human hibernation would impact space mission design.

Via ESA

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