Juno prepares to jump Jupiter’s shadow

View larger. | In this animated gif, you’re riding on the Juno spacecraft – now in orbit around Jupiter – as it approaches Jupiter. An orbit adjustment this week has ensured the solar-powered spacecraft won’t end its mission in Jupiter’s shadow on November 3. Here, you can see Jupiter’s rings and auroras. The distant sun is depicted as the yellow dot rising up just to the left of the planet. Image via NASA/JPL-Caltech/SwRI.

Since its launch in 2011, the Juno mission to Jupiter has been the little spacecraft that could, thanks to the persistence of its controllers. The craft – first to orbit Jupiter since the Galileo mission (1995-2003) – traveled nearly 2 billion miles to Jupiter and entered a highly elliptical, 53-day polar orbit around the planet on July 5, 2016. The craft was expected to enter a 14-day science orbit a few months later, but a suspected problem in Juno’s main engine nixed that idea. So Juno has remained in its 53-day orbit. It flies out a million miles from the giant planet on each circuit, then sweeps in to within 3,000 miles (5,000 km) from Jupiter’s cloudtops, all the while doing science and advancing our knowledge about our solar system’s largest planet. Then, more recently, space engineers realized that – during the solar-powered spacecraft’s next close flyby of the planet on November 3, 2019 – Juno would be flying through Jupiter’s shadow for some 12 hours. That would have been long enough to drain the spacecraft’s batteries and end the mission! But now a successful propulsive maneuver has saved the day. Its controllers confirm it will now stay out of the shadow … and survive to continue doing science.

Space engineers at NASA’s Jet Propulsion Laboratory in Pasadena, California, began executing the maneuver on September 30, 2019, at 7:46 p.m. EDT (23:46 UTC) and completed it early on October 1. In all, the maneuver lasted 10.5 hours, an extraordinarily long time by Juno mission standards. NASA said in a statement:

Using the spacecraft’s reaction-control thrusters, the propulsive maneuver lasted five times longer than any previous use of that system. It changed Juno’s orbital velocity by 126 mph (203 kph) and consumed about 160 pounds (73 kilograms) of fuel. Without this maneuver, Juno would have spent 12 hours in transit across Jupiter’s shadow – more than enough time to drain the spacecraft’s batteries. Without power, and with spacecraft temperatures plummeting, Juno would likely succumb to the cold and be unable to awaken upon exit.

Here’s the shadow of Jupiter’s moon Io, falling on Jupiter’s cloudtops, as captured by the Juno spacecraft on September 11, 2019. Citizen scientist Kevin M. Gill created this enhanced-color image using data from the spacecraft’s JunoCam imager. Read more about this image. Image via Juno Image Gallery.

Scott Bolton of the Southwest Research Institute in San Antonio is Juno’s principal investigator. He said:

With the success of this burn, we are on track to jump the shadow on November 3.

Jumping over the shadow was an amazingly creative solution to what seemed like a fatal geometry. Eclipses are generally not friends of solar-powered spacecraft. Now instead of worrying about freezing to death, I am looking forward to the next science discovery that Jupiter has in store for Juno.

Ed Hirst, Juno project manager at JPL, said:

Pre-launch mission planning did not anticipate a lengthy eclipse that would plunge our solar-powered spacecraft into darkness. That we could plan and execute the necessary maneuver while operating in Jupiter’s orbit is a testament to the ingenuity and skill of our team, along with the extraordinary capability and versatility of our spacecraft.

Thus – despite its initial difficulties and this most recent potential heart-stopper – Juno will survive to continue its mission and its contributions to science.

JunoCam’s raw images are available for the public to peruse and process into image products

Not your typical view of Jupiter, is it? Juno took the 4 images used to produce this color-enhanced view on May 29, 2019, as the spacecraft performed its 20th science pass of Jupiter. At the time the images were taken, the spacecraft was between 11,600 miles (18,600 kilometers) and 5,400 miles (8,600 kilometers) above Jupiter’s cloud tops, above a northern latitude spanning from about 59 to 34 degrees.Citizen scientist Kevin M. Gill created this image using data from the spacecraft’s JunoCam imager. Read more about this image. Image via Juno Image Gallery.

Bottom line: On September 30 to October 1, 2019, NASA’s Juno mission to Jupiter successfully executed a 10.5-hour propulsive maneuver designed to enable the spacecraft to avoid Jupiter’s shadow on November 3. Without the maneuver, the craft would have spent some 12 hours in the shadow, draining its solar-powered batteries and perhaps ending its mission.

Via NASA/JPL-Caltech

from EarthSky https://ift.tt/354BhRM

View larger. | In this animated gif, you’re riding on the Juno spacecraft – now in orbit around Jupiter – as it approaches Jupiter. An orbit adjustment this week has ensured the solar-powered spacecraft won’t end its mission in Jupiter’s shadow on November 3. Here, you can see Jupiter’s rings and auroras. The distant sun is depicted as the yellow dot rising up just to the left of the planet. Image via NASA/JPL-Caltech/SwRI.

Since its launch in 2011, the Juno mission to Jupiter has been the little spacecraft that could, thanks to the persistence of its controllers. The craft – first to orbit Jupiter since the Galileo mission (1995-2003) – traveled nearly 2 billion miles to Jupiter and entered a highly elliptical, 53-day polar orbit around the planet on July 5, 2016. The craft was expected to enter a 14-day science orbit a few months later, but a suspected problem in Juno’s main engine nixed that idea. So Juno has remained in its 53-day orbit. It flies out a million miles from the giant planet on each circuit, then sweeps in to within 3,000 miles (5,000 km) from Jupiter’s cloudtops, all the while doing science and advancing our knowledge about our solar system’s largest planet. Then, more recently, space engineers realized that – during the solar-powered spacecraft’s next close flyby of the planet on November 3, 2019 – Juno would be flying through Jupiter’s shadow for some 12 hours. That would have been long enough to drain the spacecraft’s batteries and end the mission! But now a successful propulsive maneuver has saved the day. Its controllers confirm it will now stay out of the shadow … and survive to continue doing science.

Space engineers at NASA’s Jet Propulsion Laboratory in Pasadena, California, began executing the maneuver on September 30, 2019, at 7:46 p.m. EDT (23:46 UTC) and completed it early on October 1. In all, the maneuver lasted 10.5 hours, an extraordinarily long time by Juno mission standards. NASA said in a statement:

Using the spacecraft’s reaction-control thrusters, the propulsive maneuver lasted five times longer than any previous use of that system. It changed Juno’s orbital velocity by 126 mph (203 kph) and consumed about 160 pounds (73 kilograms) of fuel. Without this maneuver, Juno would have spent 12 hours in transit across Jupiter’s shadow – more than enough time to drain the spacecraft’s batteries. Without power, and with spacecraft temperatures plummeting, Juno would likely succumb to the cold and be unable to awaken upon exit.

Here’s the shadow of Jupiter’s moon Io, falling on Jupiter’s cloudtops, as captured by the Juno spacecraft on September 11, 2019. Citizen scientist Kevin M. Gill created this enhanced-color image using data from the spacecraft’s JunoCam imager. Read more about this image. Image via Juno Image Gallery.

Scott Bolton of the Southwest Research Institute in San Antonio is Juno’s principal investigator. He said:

With the success of this burn, we are on track to jump the shadow on November 3.

Jumping over the shadow was an amazingly creative solution to what seemed like a fatal geometry. Eclipses are generally not friends of solar-powered spacecraft. Now instead of worrying about freezing to death, I am looking forward to the next science discovery that Jupiter has in store for Juno.

Ed Hirst, Juno project manager at JPL, said:

Pre-launch mission planning did not anticipate a lengthy eclipse that would plunge our solar-powered spacecraft into darkness. That we could plan and execute the necessary maneuver while operating in Jupiter’s orbit is a testament to the ingenuity and skill of our team, along with the extraordinary capability and versatility of our spacecraft.

Thus – despite its initial difficulties and this most recent potential heart-stopper – Juno will survive to continue its mission and its contributions to science.

JunoCam’s raw images are available for the public to peruse and process into image products

Not your typical view of Jupiter, is it? Juno took the 4 images used to produce this color-enhanced view on May 29, 2019, as the spacecraft performed its 20th science pass of Jupiter. At the time the images were taken, the spacecraft was between 11,600 miles (18,600 kilometers) and 5,400 miles (8,600 kilometers) above Jupiter’s cloud tops, above a northern latitude spanning from about 59 to 34 degrees.Citizen scientist Kevin M. Gill created this image using data from the spacecraft’s JunoCam imager. Read more about this image. Image via Juno Image Gallery.

Bottom line: On September 30 to October 1, 2019, NASA’s Juno mission to Jupiter successfully executed a 10.5-hour propulsive maneuver designed to enable the spacecraft to avoid Jupiter’s shadow on November 3. Without the maneuver, the craft would have spent some 12 hours in the shadow, draining its solar-powered batteries and perhaps ending its mission.

Via NASA/JPL-Caltech

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Minuteman III launch

Image via Alex Ustick.

The Minuteman III intercontinental ballistic test missile launched at 1:13 a.m. PT (8:13 UTC) Wednesday, October 2, 2019, from Vandenberg Air Force Base in Lompoc, California.

Test launches like this one typically happen several times a year at Vandenberg Air Force Base.

Thanks for sharing your image with us, Alex!

from EarthSky https://ift.tt/2Oiv7re

Image via Alex Ustick.

The Minuteman III intercontinental ballistic test missile launched at 1:13 a.m. PT (8:13 UTC) Wednesday, October 2, 2019, from Vandenberg Air Force Base in Lompoc, California.

Test launches like this one typically happen several times a year at Vandenberg Air Force Base.

Thanks for sharing your image with us, Alex!

from EarthSky https://ift.tt/2Oiv7re

Listen to the sounds of Mars

Clouds drift over the dome-covered seismometer, known as SEIS, belonging to NASA’s InSight lander, on Mars. Image via NASA/JPL-Caltech.

NASA’s Mars InSight lander has had its ear to the ground since it arrived on the planet in November 2018. The spacecraft’s “ear” is an exquisitely sensitive seismometer, called SEIS (Seismic Experiment for Interior Structure), that can pick up vibrations as subtle as a breeze.

SEIS was designed to listen for marsquakes, quakes which, much like earthquakes, are the shaking of Mars’ surface or interior as a result of the sudden release of energy inside the planet. But after the seismometer was set down by InSight’s robotic arm on December 19, 2018, Mars didn’t produce a rumbling until April 2019, and this first quake turned out to be an “odd duck,” said NASA. That’s because it turned out to have a surprisingly high-frequency seismic signal, compared to what the science team has heard since. Out of more than 100 events detected to date, about 21 are strongly considered to be quakes. The remainder could be quakes as well, but the science team hasn’t ruled out other causes.

To really hear what’s happening in the recordings below, it’s best to wear headphones. They are recordings of two of the more representative quakes SEIS has detected. These occurred on May 22 and July 25, 2019. Because they’re far below the human range of hearing, these sonifications from SEIS had to be speeded up and slightly processed to be audible through headphones.

The May 22 quake is about a magnitude 3.7 and the July 25 quake is about a magnitude 3.3. Each quake is a subtle rumble. The July 25 quake becomes particularly bass-heavy toward the end of the event.

May 22, 2019

July 25, 2019

NASA said:

Both suggest that the Martian crust is like a mix of the Earth’s crust and the moon’s. Cracks in Earth’s crust seal over time as water fills them with new minerals. This enables sound waves to continue uninterrupted as they pass through old fractures. Drier crusts like the Moon’s remain fractured after impacts, scattering sound waves for tens of minutes rather than allowing them to travel in a straight line. Mars, with its cratered surface, is slightly more moon-like, with seismic waves ringing for a minute or so, whereas quakes on Earth can come and go in seconds.

SEIS has no trouble identifying quiet quakes, but its sensitive ear means scientists have lots of other noises to filter out. Over time, the team has learned to recognize the different sounds. Some are trickier than others to spot. The recording below, also best heard with headphones, captures the array of sounds the science team is hearing.

On March 6, 2019, a camera on InSight’s robotic arm was scanning the surface in front of the lander. Each movement of the arm produces what to SEIS is a piercing noise.

Wind gusts can also create noise. The team is always on the hunt for quakes, but they’ve found the twilight hours are one of the best times to listen for marsquakes. Thaat’s because during the day, sunlight warms the air and creates more wind interference than at night.

Evening is also when peculiar sounds that the InSight team has nicknamed “dinks and donks” become more prevalent. The team knows they’re coming from delicate parts within the seismometer expanding and contracting against one another and thinks heat loss may be the factor, similar to how a car engine “ticks” after it’s turned off and begins cooling.

Listen for these dinks and donks in the set of sounds, below, recorded just after sundown on July 16, 2019. If you listen carefully, you can also pick out an eerie whistling that the team thinks may be caused by interference in the seismometer’s electronics.

The SEIS instrument was provided by the French space agency, Centre National d’Études Spatiales (CNES), and its partners. Insight team members Constantinos Charalambous of Imperial College London and Nobuaki Fuji of Institut de Physique du Globe de Paris provided the audio samples for this story.

Bottom line: Listen to recordings of sounds detected on Mars by the Insight lander.

Via NASA/JPL

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

Clouds drift over the dome-covered seismometer, known as SEIS, belonging to NASA’s InSight lander, on Mars. Image via NASA/JPL-Caltech.

NASA’s Mars InSight lander has had its ear to the ground since it arrived on the planet in November 2018. The spacecraft’s “ear” is an exquisitely sensitive seismometer, called SEIS (Seismic Experiment for Interior Structure), that can pick up vibrations as subtle as a breeze.

SEIS was designed to listen for marsquakes, quakes which, much like earthquakes, are the shaking of Mars’ surface or interior as a result of the sudden release of energy inside the planet. But after the seismometer was set down by InSight’s robotic arm on December 19, 2018, Mars didn’t produce a rumbling until April 2019, and this first quake turned out to be an “odd duck,” said NASA. That’s because it turned out to have a surprisingly high-frequency seismic signal, compared to what the science team has heard since. Out of more than 100 events detected to date, about 21 are strongly considered to be quakes. The remainder could be quakes as well, but the science team hasn’t ruled out other causes.

To really hear what’s happening in the recordings below, it’s best to wear headphones. They are recordings of two of the more representative quakes SEIS has detected. These occurred on May 22 and July 25, 2019. Because they’re far below the human range of hearing, these sonifications from SEIS had to be speeded up and slightly processed to be audible through headphones.

The May 22 quake is about a magnitude 3.7 and the July 25 quake is about a magnitude 3.3. Each quake is a subtle rumble. The July 25 quake becomes particularly bass-heavy toward the end of the event.

May 22, 2019

July 25, 2019

NASA said:

Both suggest that the Martian crust is like a mix of the Earth’s crust and the moon’s. Cracks in Earth’s crust seal over time as water fills them with new minerals. This enables sound waves to continue uninterrupted as they pass through old fractures. Drier crusts like the Moon’s remain fractured after impacts, scattering sound waves for tens of minutes rather than allowing them to travel in a straight line. Mars, with its cratered surface, is slightly more moon-like, with seismic waves ringing for a minute or so, whereas quakes on Earth can come and go in seconds.

SEIS has no trouble identifying quiet quakes, but its sensitive ear means scientists have lots of other noises to filter out. Over time, the team has learned to recognize the different sounds. Some are trickier than others to spot. The recording below, also best heard with headphones, captures the array of sounds the science team is hearing.

On March 6, 2019, a camera on InSight’s robotic arm was scanning the surface in front of the lander. Each movement of the arm produces what to SEIS is a piercing noise.

Wind gusts can also create noise. The team is always on the hunt for quakes, but they’ve found the twilight hours are one of the best times to listen for marsquakes. Thaat’s because during the day, sunlight warms the air and creates more wind interference than at night.

Evening is also when peculiar sounds that the InSight team has nicknamed “dinks and donks” become more prevalent. The team knows they’re coming from delicate parts within the seismometer expanding and contracting against one another and thinks heat loss may be the factor, similar to how a car engine “ticks” after it’s turned off and begins cooling.

Listen for these dinks and donks in the set of sounds, below, recorded just after sundown on July 16, 2019. If you listen carefully, you can also pick out an eerie whistling that the team thinks may be caused by interference in the seismometer’s electronics.

The SEIS instrument was provided by the French space agency, Centre National d’Études Spatiales (CNES), and its partners. Insight team members Constantinos Charalambous of Imperial College London and Nobuaki Fuji of Institut de Physique du Globe de Paris provided the audio samples for this story.

Bottom line: Listen to recordings of sounds detected on Mars by the Insight lander.

Via NASA/JPL

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

Moon and Jupiter close October 3 and 4

On October 3, 2019, watch for the waxing crescent moon to pop out into the evening twilight. The king planet Jupiter – brightest of all the “stars” in the sky after true darkness falls – will be the first to pop into view nearby. You won’t want to miss the attractive evening couple at nightfall on October 3. They’ll be closest on that evening. The following evening, October 4, the moon will have moved past Jupiter, moving, as it always does, toward the east in orbit around Earth. Watch, as the moon waxes in phase and moves up toward Saturn, which it will pass around October 5.

Although our featured sky chart at top is especially for North America, the moon nonetheless appears quite close to Jupiter as seen from around the world. For your specific view, try Stellarium Online.

Jupiter ranks as the fourth-brightest celestial object to light up the sky, after the sun, moon and Venus. It’s highly unlikely that you’ll mistake Venus, the third-brightest celestial object, for Jupiter, or vice versa. Venus sits low in the sky at sunset and is obscured in the afterglow of sunset now, especially from Northern Hemisphere locations. Venus sinks beneath the horizon soon after sunset, but the moon and Jupiter stay out past nightfall, well into the evening. You’ll find them out until mid-evening at mid-northern latitudes and until late evening in the Southern Hemisphere.

As darkness falls, you might spot a twinkly ruddy star popping out in the vicinity of the moon and Jupiter. That’s Antares, the brightest star in the constellation Scorpius the Scorpion. Although a 1st-magnitude star, Antares pales next to Jupiter, which outshines Antares by some 16 times.

As always, the moon goes full circle in front of the constellations of the zodiac every month. The dark side of the waxing moon always points in the moon’s direction of travel: eastward.

Day by day, Jupiter and Saturn are sinking a bit lower in the evening sky. Venus, on the other hand, is climbing upward day by day. So Venus will meet up with Jupiter for a close-knit conjunction on November 24, 2019, and then with Saturn for another close-knit conjunction on December 11, 2019 (December 10 in North America).

Visit Heavens-Above to know the moon’s position relative to the bright planets and the constellations of the zodiac.

Click here for a sky almanac providing the setting times for the sun, moon and planets in your sky.

Eleven Earths could line up side by side to equal the diameter of the king planet Jupiter. Image via Wikimedia Commons.

Bottom line: Use the moon to locate Jupiter and Saturn in early October. Then watch for Venus to climb upward and to eventually meet up with these planets in the evening sky in November and December.

from EarthSky https://ift.tt/2pAga9R

On October 3, 2019, watch for the waxing crescent moon to pop out into the evening twilight. The king planet Jupiter – brightest of all the “stars” in the sky after true darkness falls – will be the first to pop into view nearby. You won’t want to miss the attractive evening couple at nightfall on October 3. They’ll be closest on that evening. The following evening, October 4, the moon will have moved past Jupiter, moving, as it always does, toward the east in orbit around Earth. Watch, as the moon waxes in phase and moves up toward Saturn, which it will pass around October 5.

Although our featured sky chart at top is especially for North America, the moon nonetheless appears quite close to Jupiter as seen from around the world. For your specific view, try Stellarium Online.

Jupiter ranks as the fourth-brightest celestial object to light up the sky, after the sun, moon and Venus. It’s highly unlikely that you’ll mistake Venus, the third-brightest celestial object, for Jupiter, or vice versa. Venus sits low in the sky at sunset and is obscured in the afterglow of sunset now, especially from Northern Hemisphere locations. Venus sinks beneath the horizon soon after sunset, but the moon and Jupiter stay out past nightfall, well into the evening. You’ll find them out until mid-evening at mid-northern latitudes and until late evening in the Southern Hemisphere.

As darkness falls, you might spot a twinkly ruddy star popping out in the vicinity of the moon and Jupiter. That’s Antares, the brightest star in the constellation Scorpius the Scorpion. Although a 1st-magnitude star, Antares pales next to Jupiter, which outshines Antares by some 16 times.

As always, the moon goes full circle in front of the constellations of the zodiac every month. The dark side of the waxing moon always points in the moon’s direction of travel: eastward.

Day by day, Jupiter and Saturn are sinking a bit lower in the evening sky. Venus, on the other hand, is climbing upward day by day. So Venus will meet up with Jupiter for a close-knit conjunction on November 24, 2019, and then with Saturn for another close-knit conjunction on December 11, 2019 (December 10 in North America).

Visit Heavens-Above to know the moon’s position relative to the bright planets and the constellations of the zodiac.

Click here for a sky almanac providing the setting times for the sun, moon and planets in your sky.

Eleven Earths could line up side by side to equal the diameter of the king planet Jupiter. Image via Wikimedia Commons.

Bottom line: Use the moon to locate Jupiter and Saturn in early October. Then watch for Venus to climb upward and to eventually meet up with these planets in the evening sky in November and December.

from EarthSky https://ift.tt/2pAga9R

Why leaves change color in fall

Vermont, September 29, 2019. Image via Abhijit Patil.

Throughout the spring and summer, the deep green color of chlorophyll, which helps plants absorb life-giving sunlight, hides any other colors present in the leaves of trees. The vivid yellows and oranges of fall leaves are there, but hidden. In the fall, trees break down the green pigments and nutrients stored in their leaves. The nutrients are shuttled into the tree’s roots for reuse in the spring. It’s then that the trees take on their autumn hues.

As leaves lose their chlorophyll, other pigments become visible to the human eye, according to Bryan A. Hanson, professor of chemistry and biochemistry at DePauw University who studies plant pigments. Some tree leaves turn mostly brown, indicating that all pigments are gone.

Scott Kuhn wrote: “Leaves popping with color this weekend in North Georgia.”

Autumn in the Colorado Rocky Mountains. Photo via Jessi Leigh.

Autumn leaves at Hurricane Mountain in the Adirondacks, New York. Photo via John Holmes.

Autumn leaf in about mid-September from our friend Colin Chatfield in Saskatoon, Saskatchewan.

Steven Arthur Sweet captured this image at Centennial Park in Toronto, Canada.

Burgundy and red colors are a different story. Dana A. Dudle is a DePauw professor of biology who researches red pigment in plant flowers, stems and leaves. Dudle said:

The red color is actively made in leaves by bright light and cold. The crisp, cold nights in the fall combine with bright, sunny days to spur production of red in leaves – especially in sugar maple and red maple trees. Burgundy leaves often result from a combination of red pigment and chlorophyll. Autumn seasons with a lot of sunny days and cold nights will have the brightest colors.

Image via treehouse1977.

In some cases, about half of a tree’s leaves are red/orange and the other half green. Dudle says that results from micro-environmental factors – such as only half the tree being exposed to sunlight or cold.

Hardwoods in the Midwest and on the East Coast are famous for good color selections. Some of the more reliably colorful trees, Hanson notes, are liquidambar trees (also called sweetgum) that turn a variety of colors on the same tree, and sometimes the same leaf. Ash tree leaves often turn a deep burgundy color. Ginkgo trees, although not native to North America, will feature an intense yellow, almost golden, color.

A lone red tree against bare branches. Photo via Daniel de Leeuw Photog.

“Autumn picture from Sweden…” from our friend Jörgen Norrland
.

The colors are doing something for the plant, or they wouldn’t be there, said Hansen. But what is the colors’ purpose?

Scientists think that with some trees, pigments serve as a kind of sunscreen to filter out sunlight. Hanson said:

It’s an underappreciated fact that plants cannot take an infinite amount of sun. Some leaves, if they get too much sun, will get something equivalent of a sunburn. They get stressed out and die.

Image via Tosca Yemoh Zanon in London.

Another theory is that the color of a plant’s leaves is often related to the ability to warn away pests or attract insect pollinators. Hanson said:

In some cases, a plant and insect might have co-evolved. One of the more intriguing scientific theories is that the beautiful leaf colors we see today are indicative of a relationship between a plant and insects that developed millions of years ago. However, as the Earth’s climate changed over the years, the insects might have gone extinct, but the plant was able to survive for whatever reason.

Because plants evolve very slowly, we still see the colors. So leaf color is a fossil memory, something that existed for a reason millions of years ago but that serves no purpose now.

Early October in Hibbing, Minnesota. Photo via EarthSky Facebook friend Rosalbina Segura.

Bottom line: Biologists discuss why leaves change color in the fall.

Read more from DePauw University

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

Vermont, September 29, 2019. Image via Abhijit Patil.

Throughout the spring and summer, the deep green color of chlorophyll, which helps plants absorb life-giving sunlight, hides any other colors present in the leaves of trees. The vivid yellows and oranges of fall leaves are there, but hidden. In the fall, trees break down the green pigments and nutrients stored in their leaves. The nutrients are shuttled into the tree’s roots for reuse in the spring. It’s then that the trees take on their autumn hues.

As leaves lose their chlorophyll, other pigments become visible to the human eye, according to Bryan A. Hanson, professor of chemistry and biochemistry at DePauw University who studies plant pigments. Some tree leaves turn mostly brown, indicating that all pigments are gone.

Scott Kuhn wrote: “Leaves popping with color this weekend in North Georgia.”

Autumn in the Colorado Rocky Mountains. Photo via Jessi Leigh.

Autumn leaves at Hurricane Mountain in the Adirondacks, New York. Photo via John Holmes.

Autumn leaf in about mid-September from our friend Colin Chatfield in Saskatoon, Saskatchewan.

Steven Arthur Sweet captured this image at Centennial Park in Toronto, Canada.

Burgundy and red colors are a different story. Dana A. Dudle is a DePauw professor of biology who researches red pigment in plant flowers, stems and leaves. Dudle said:

The red color is actively made in leaves by bright light and cold. The crisp, cold nights in the fall combine with bright, sunny days to spur production of red in leaves – especially in sugar maple and red maple trees. Burgundy leaves often result from a combination of red pigment and chlorophyll. Autumn seasons with a lot of sunny days and cold nights will have the brightest colors.

Image via treehouse1977.

In some cases, about half of a tree’s leaves are red/orange and the other half green. Dudle says that results from micro-environmental factors – such as only half the tree being exposed to sunlight or cold.

Hardwoods in the Midwest and on the East Coast are famous for good color selections. Some of the more reliably colorful trees, Hanson notes, are liquidambar trees (also called sweetgum) that turn a variety of colors on the same tree, and sometimes the same leaf. Ash tree leaves often turn a deep burgundy color. Ginkgo trees, although not native to North America, will feature an intense yellow, almost golden, color.

A lone red tree against bare branches. Photo via Daniel de Leeuw Photog.

“Autumn picture from Sweden…” from our friend Jörgen Norrland
.

The colors are doing something for the plant, or they wouldn’t be there, said Hansen. But what is the colors’ purpose?

Scientists think that with some trees, pigments serve as a kind of sunscreen to filter out sunlight. Hanson said:

It’s an underappreciated fact that plants cannot take an infinite amount of sun. Some leaves, if they get too much sun, will get something equivalent of a sunburn. They get stressed out and die.

Image via Tosca Yemoh Zanon in London.

Another theory is that the color of a plant’s leaves is often related to the ability to warn away pests or attract insect pollinators. Hanson said:

In some cases, a plant and insect might have co-evolved. One of the more intriguing scientific theories is that the beautiful leaf colors we see today are indicative of a relationship between a plant and insects that developed millions of years ago. However, as the Earth’s climate changed over the years, the insects might have gone extinct, but the plant was able to survive for whatever reason.

Because plants evolve very slowly, we still see the colors. So leaf color is a fossil memory, something that existed for a reason millions of years ago but that serves no purpose now.

Early October in Hibbing, Minnesota. Photo via EarthSky Facebook friend Rosalbina Segura.

Bottom line: Biologists discuss why leaves change color in the fall.

Read more from DePauw University

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

The key is collaboration: ‘You need to work across borders, and that’s what I do on a daily basis’

Dr Susanne Gatz, originally from Germany, works as a children’s cancer doctor and researcher at the Cancer Research UK Clinical Trials Unit at the University of Birmingham. Typical of cancer researchers in the UK, Gatz requires easy movement across Europe to do her job.

With the Government redesigning the immigration system, a change that will impact all scientists moving between the UK and EU, we spoke to Gatz about her experience of travelling across Europe for work.

“It’s quite diverse work” says Gatz, “I’m a clinical academic, which means on the one hand I am treating children with cancer and on the other hand I am researching how we can improve treatments for these children.”

These different roles mean there’s no typical day for Gatz. Work can involve anything from seeing patients and their families to discussing projects in the lab, but a lot of her time is spent travelling across Europe and beyond to meet colleagues in different countries who are working towards the same goal: helping more children survive their cancer.

‘It’s exciting to get up in the morning’

Researching children’s cancers is challenging, but Gatz finds it hugely rewarding. “It’s exciting because of all the opportunities we have in cancer drug development to improve outcomes for children with cancer.”

One opportunity she mentions is a clinical trial for children and young adults with a rare form of soft tissue cancer, called rhabdomyosarcoma (RMS).

“For the first time, we can include patients who have just been diagnosed and patients who have relapsed or are progressing in a single trial. This is a really big deal and I’m involved in trying to access new medicines that can be tested in the trial, which is promising for such a rare cancer.”

The Far-RMS trial would not be possible without international collaboration. With such low numbers of patients in individual countries, the trial must be run across several. Working together like this should help speed up new and better treatments for children with rhabdomyosarcoma.

‘You cannot work as one country’

Gatz travels regularly for work, saying it’s vital to help scientists ‘broaden their horizons’.

“A key thing to our research is to be at meetings with colleagues outside your institutions, to broaden your horizons. This is really important in rare diseases such as paediatric cancers where you need to team up to make discoveries but to also treat effectively and run clinical trials.”

Email and teleconferences help Gatz stay in touch with international colleagues, but face-to-face meetings play a vital role too.

“That’s where we discuss the biggest issues we face. This is really important because you can talk with so many different people and it’s often where we drive projects forward and create new ideas.”

Without quick, visa-free movement of researchers across borders, it would be difficult for these meetings to take place. And when collaborating across borders is the quickest and best way to find treatments for children’s cancers, countries can’t afford to put up barriers.

“We already have long days, but at least at the moment I can wake up at 4am and head straight to the airport and then get to a meeting for 9am,” says Gatz. “If I couldn’t, it would be enormously burdensome, and I would lose time. This would make it more expensive and harder to make agreements with fellow researchers.”

Working across borders is a must in Gatz’s research, and she clearly has a strong bond with her international colleagues.

“Whether it is my clinical role or research role, I feel that together with my international colleagues and collaborators, we can step by step make a difference.”

‘The UK’s openness made me feel welcome’

Gatz’s interest in children’s cancers began in Germany, where she did her medical training and studied for a PhD.

“I decided to come to the UK in 2008 to do more research. I really liked the research environment in the UK as it allowed me to bring together my interests in medicine development with my passion for paediatric oncology.”

Straightforward travel to and from Gatz’s home of Germany made her decision to move here simple.

“Easy movement definitely played a role in my decision to move to the UK. All of the research I was interested in at the time was from either the UK or US, so when it came to decide where to move, the UK was the obvious choice.”

But with the UK’s future relationship with the EU bringing so much uncertainty, Gatz is beginning to reconsider her options. “I have considered going back to Germany and actively pursued the option. I probably would have continued to pursue this if I hadn’t secured a permanent position here in Birmingham.”

And it’s vital for Gatz that our future immigration system lets researchers like her feel that they can do their jobs by travelling easily across Europe.

“I hope we are successful in identifying a way to keep easy movement between UK and EU. It would make life for researchers much easier and give our research the security it needs.”

Angeliki Yiangou is a policy advisor at Cancer Research UK 

Find out more:

• Blog post: ‘There are scientists from all over the world at my institute, working to accelerate progress in cancer research’  
• Why international scientists are so important to our work
• Our Q&A on immigration and cancer

from Cancer Research UK – Science blog https://ift.tt/2pe9q14

Dr Susanne Gatz, originally from Germany, works as a children’s cancer doctor and researcher at the Cancer Research UK Clinical Trials Unit at the University of Birmingham. Typical of cancer researchers in the UK, Gatz requires easy movement across Europe to do her job.

With the Government redesigning the immigration system, a change that will impact all scientists moving between the UK and EU, we spoke to Gatz about her experience of travelling across Europe for work.

“It’s quite diverse work” says Gatz, “I’m a clinical academic, which means on the one hand I am treating children with cancer and on the other hand I am researching how we can improve treatments for these children.”

These different roles mean there’s no typical day for Gatz. Work can involve anything from seeing patients and their families to discussing projects in the lab, but a lot of her time is spent travelling across Europe and beyond to meet colleagues in different countries who are working towards the same goal: helping more children survive their cancer.

‘It’s exciting to get up in the morning’

Researching children’s cancers is challenging, but Gatz finds it hugely rewarding. “It’s exciting because of all the opportunities we have in cancer drug development to improve outcomes for children with cancer.”

One opportunity she mentions is a clinical trial for children and young adults with a rare form of soft tissue cancer, called rhabdomyosarcoma (RMS).

“For the first time, we can include patients who have just been diagnosed and patients who have relapsed or are progressing in a single trial. This is a really big deal and I’m involved in trying to access new medicines that can be tested in the trial, which is promising for such a rare cancer.”

The Far-RMS trial would not be possible without international collaboration. With such low numbers of patients in individual countries, the trial must be run across several. Working together like this should help speed up new and better treatments for children with rhabdomyosarcoma.

‘You cannot work as one country’

Gatz travels regularly for work, saying it’s vital to help scientists ‘broaden their horizons’.

“A key thing to our research is to be at meetings with colleagues outside your institutions, to broaden your horizons. This is really important in rare diseases such as paediatric cancers where you need to team up to make discoveries but to also treat effectively and run clinical trials.”

Email and teleconferences help Gatz stay in touch with international colleagues, but face-to-face meetings play a vital role too.

“That’s where we discuss the biggest issues we face. This is really important because you can talk with so many different people and it’s often where we drive projects forward and create new ideas.”

Without quick, visa-free movement of researchers across borders, it would be difficult for these meetings to take place. And when collaborating across borders is the quickest and best way to find treatments for children’s cancers, countries can’t afford to put up barriers.

“We already have long days, but at least at the moment I can wake up at 4am and head straight to the airport and then get to a meeting for 9am,” says Gatz. “If I couldn’t, it would be enormously burdensome, and I would lose time. This would make it more expensive and harder to make agreements with fellow researchers.”

Working across borders is a must in Gatz’s research, and she clearly has a strong bond with her international colleagues.

“Whether it is my clinical role or research role, I feel that together with my international colleagues and collaborators, we can step by step make a difference.”

‘The UK’s openness made me feel welcome’

Gatz’s interest in children’s cancers began in Germany, where she did her medical training and studied for a PhD.

“I decided to come to the UK in 2008 to do more research. I really liked the research environment in the UK as it allowed me to bring together my interests in medicine development with my passion for paediatric oncology.”

Straightforward travel to and from Gatz’s home of Germany made her decision to move here simple.

“Easy movement definitely played a role in my decision to move to the UK. All of the research I was interested in at the time was from either the UK or US, so when it came to decide where to move, the UK was the obvious choice.”

But with the UK’s future relationship with the EU bringing so much uncertainty, Gatz is beginning to reconsider her options. “I have considered going back to Germany and actively pursued the option. I probably would have continued to pursue this if I hadn’t secured a permanent position here in Birmingham.”

And it’s vital for Gatz that our future immigration system lets researchers like her feel that they can do their jobs by travelling easily across Europe.

“I hope we are successful in identifying a way to keep easy movement between UK and EU. It would make life for researchers much easier and give our research the security it needs.”

Angeliki Yiangou is a policy advisor at Cancer Research UK 

Find out more:

• Blog post: ‘There are scientists from all over the world at my institute, working to accelerate progress in cancer research’  
• Why international scientists are so important to our work
• Our Q&A on immigration and cancer

from Cancer Research UK – Science blog https://ift.tt/2pe9q14

Astronomers spy cosmic bubbles and bow shocks

Yellow circles and ovals outline star-forming bubbles in this infrared image from NASA’s Spitzer Space Telescope. This region – in the direction of our constellation Aquila the Eagle – is full of these bubbles, which are being blown by young stars. The bubbles are estimated to be 10 to 30 light-years across. Image via the Spitzer mission.

Multiple bubbles and bow shocks from young stars seen in this new infrared image from the Spitzer Space Telescope were recently identified as part of The Milky Way Project, a citizen science initiative on Zooniverse.org. The project enabled citizen scientists to look through images from Spitzer’s public data archive and identify as many of these sorts of cosmic bubbles as they could. More than 78,000 unique user accounts contributed, which enabled astronomers to publish a catalog of the bubble candidates that multiple citizen scientists had identified. The full Milky Way Project catalogs, which list a total of 2,600 bubbles and 599 bow shocks, are described in a paper published recently in Monthly Notices of the Royal Astronomical Society. This new infrared image from the Spitzer Space Telescope was made possible by this work; it enabled astronomers to know where to look. The image shows a cloud of gas and dust full of bubbles, which are inflated by wind and radiation from young, massive stars. Each bubble is filled with hundreds to thousands of stars, which form from dense clouds of gas and dust.

NASA said in a statement on September 30, 2019:

The bubbles are estimated to be 10 to 30 light-years across, based on what astronomers know about them and other cosmic bubbles. However, determining the exact sizes of individual bubbles can be difficult, because their distance from Earth is challenging to measure and objects appear smaller the farther away they are.

Flows of particles emitted by the stars, called stellar winds, as well as the pressure of the light the stars produce, can push the surrounding material outward, sometimes creating a distinct perimeter.

In an accompanying annotated image, yellow circles and ovals outline more than 30 bubbles.

This active region of star formation is located within the Milky Way galaxy, in the constellation Aquila (also known as the Eagle). Black veins running throughout the cloud are regions of especially dense cold dust and gas where even more new stars are likely to form.

Spitzer sees infrared light, which isn’t visible to the human eye. Many interstellar nebulas (clouds of gas and dust in space) like this one are best observed in infrared light because infrared wavelengths can pass through intervening layers of dust in the Milky Way galaxy. Visible light, however, tends to be blocked more by dust.

The colors in this image represent different wavelengths of infrared light. Blue represents a wavelength of light primarily emitted by stars; dust and organic molecules called hydrocarbons appear green, and warm dust that’s been heated by stars appears red.

Also visible are four bow shocks – red arcs of warm dust formed as winds from fast-moving stars push aside dust grains scattered sparsely through most of the nebula. The locations of the bow shocks are indicated by squares in the annotated image and shown close up in the accompanying detail images.

View larger. | Close-ups of the 4 bow shocks, via NASA’s Spitzer Space Telescope.

Bottom line: Citizen scientists identified a total of 2,600 bubbles and 599 bow shocks from young, hot stars. A new NASA Spitzer Space Telescope image shows one of these regions.

Source: The Milky Way Project second data release: bubbles and bow shocks

Via NASA

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

Yellow circles and ovals outline star-forming bubbles in this infrared image from NASA’s Spitzer Space Telescope. This region – in the direction of our constellation Aquila the Eagle – is full of these bubbles, which are being blown by young stars. The bubbles are estimated to be 10 to 30 light-years across. Image via the Spitzer mission.

Multiple bubbles and bow shocks from young stars seen in this new infrared image from the Spitzer Space Telescope were recently identified as part of The Milky Way Project, a citizen science initiative on Zooniverse.org. The project enabled citizen scientists to look through images from Spitzer’s public data archive and identify as many of these sorts of cosmic bubbles as they could. More than 78,000 unique user accounts contributed, which enabled astronomers to publish a catalog of the bubble candidates that multiple citizen scientists had identified. The full Milky Way Project catalogs, which list a total of 2,600 bubbles and 599 bow shocks, are described in a paper published recently in Monthly Notices of the Royal Astronomical Society. This new infrared image from the Spitzer Space Telescope was made possible by this work; it enabled astronomers to know where to look. The image shows a cloud of gas and dust full of bubbles, which are inflated by wind and radiation from young, massive stars. Each bubble is filled with hundreds to thousands of stars, which form from dense clouds of gas and dust.

NASA said in a statement on September 30, 2019:

The bubbles are estimated to be 10 to 30 light-years across, based on what astronomers know about them and other cosmic bubbles. However, determining the exact sizes of individual bubbles can be difficult, because their distance from Earth is challenging to measure and objects appear smaller the farther away they are.

Flows of particles emitted by the stars, called stellar winds, as well as the pressure of the light the stars produce, can push the surrounding material outward, sometimes creating a distinct perimeter.

In an accompanying annotated image, yellow circles and ovals outline more than 30 bubbles.

This active region of star formation is located within the Milky Way galaxy, in the constellation Aquila (also known as the Eagle). Black veins running throughout the cloud are regions of especially dense cold dust and gas where even more new stars are likely to form.

Spitzer sees infrared light, which isn’t visible to the human eye. Many interstellar nebulas (clouds of gas and dust in space) like this one are best observed in infrared light because infrared wavelengths can pass through intervening layers of dust in the Milky Way galaxy. Visible light, however, tends to be blocked more by dust.

The colors in this image represent different wavelengths of infrared light. Blue represents a wavelength of light primarily emitted by stars; dust and organic molecules called hydrocarbons appear green, and warm dust that’s been heated by stars appears red.

Also visible are four bow shocks – red arcs of warm dust formed as winds from fast-moving stars push aside dust grains scattered sparsely through most of the nebula. The locations of the bow shocks are indicated by squares in the annotated image and shown close up in the accompanying detail images.

View larger. | Close-ups of the 4 bow shocks, via NASA’s Spitzer Space Telescope.

Bottom line: Citizen scientists identified a total of 2,600 bubbles and 599 bow shocks from young, hot stars. A new NASA Spitzer Space Telescope image shows one of these regions.

Source: The Milky Way Project second data release: bubbles and bow shocks

Via NASA

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