Estimating the odds for intelligent life in the multiverse

This Hubble Space Telescope image captures a triple-star system, which can host potentially habitable planets. Our nearest stellar neighbor, the Alpha Centauri system, includes 3 stars. A team of astronomers recently estimated the chances for intelligent life in our universe and other possible universes. They did so by looking at how different densities of dark matter affect star formation. Image via NASA/ ESA/ G. Duchene (Universite de Grenoble I)/ Royal Astronomical Society. Image processing via Gladys Kober (NASA/Catholic University of America). CC BY 4.0.

• Intelligent life in the universe requires the existence of stars and worlds around stars, as far as we know.
• Stars form from clumps of matter, and this structure is possible thanks to a universe where dark energy makes the universe expand faster to balance gravity’s inward pull.
• Of all possible universes, a new study found that our universe might not even be the best possible universe for forming life.

The Royal Astronomical Society published this original story at 00:01 GMT on November 13, 2024. Edits by EarthSky.

Estimating the chances for intelligent life

The chances of intelligent life emerging in our universe – and in any hypothetical ones beyond it – is something astronomers have now estimated, using a new theoretical model with echoes of the famous Drake Equation. This was the formula that American astronomer Frank Drake came up with in the 1960s to calculate the number of detectable extraterrestrial civilizations in our Milky Way galaxy.

More than 60 years on, astrophysicists led by Durham University have produced a different model, which instead focuses on the conditions created by the acceleration of the universe’s expansion and the amount of stars formed.

It is thought this expansion is being driven by a mysterious force called dark energy that makes up more than 2/3s of the universe.

The peer-reviewed Monthly Notices of the Royal Astronomical Society published the study on November 13, 2024.

What is the calculation?

Stars are a precondition for the emergence of life as we know it. So the model could therefore be used to estimate the probability of generating intelligent life in our universe, and in a multiverse scenario of hypothetical different universes.

The new research does not attempt to calculate the absolute number of observers (i.e. intelligent life) in the universe. But instead it considers the relative probability of a randomly chosen observer inhabiting a universe with particular properties.

It concludes that a typical observer would expect to experience a substantially larger density of dark energy than we see in our own universe. And that suggests the ingredients our universe possesses make it a rare and unusual case in the multiverse.

The approach presented in the paper involves calculating the fraction of ordinary matter converted into stars over the entire history of the universe, for different dark-energy densities.

The model predicts this fraction would be approximately 27% in a universe that is most efficient at forming stars, compared to 23% in our own universe.

This means we don’t live in the hypothetical universe with the highest odds of forming intelligent lifeforms. Or in other words, the value of dark energy density we observe in our universe is not the one that would maximize the chances of life, according to the model.

Dark energy’s impact on our existence

Lead researcher Daniele Sorini, of Durham University’s Institute for Computational Cosmology, said:

Understanding dark energy and the impact on our universe is one of the biggest challenges in cosmology and fundamental physics.

The parameters that govern our universe, including the density of dark energy, could explain our own existence.

Surprisingly, though, we found that even a significantly higher dark energy density would still be compatible with life, suggesting we may not live in the most likely of universes.

The new model could allow scientists to understand the effects of differing densities of dark energy on the formation of structures in the universe and the conditions for life to develop in the cosmos.

The role of dark energy in intelligent life

Dark energy makes the universe expand faster, balancing gravity’s pull and creating a universe where both expansion and structure formation are possible.

However, for life to develop, there would need to be regions where matter can clump together to form stars and planets, and it would need to remain stable for billions of years to allow life to evolve.

Crucially, the research suggests that the astrophysics of star formation and the evolution of the large-scale structure of the universe combine in a subtle way to determine the optimal value of the dark energy density needed for the generation of intelligent life.

Lucas Lombriser, Université de Genève and co-author of the study, added:

It will be exciting to employ the model to explore the emergence of life across different universes and see whether some fundamental questions we ask ourselves about our own universe must be reinterpreted.

How the same region of the universe would look in terms of the amount of stars for different values of the dark energy density. Clockwise, from top left: no dark energy, same dark energy density as in our universe, 30 times the dark energy density in our universe and 10 times the dark energy density in our universe. The images are generated from a suite of cosmological simulations. Image via Oscar Veenema/ Royal Astronomical Society/ CC BY 4.0.

Drake Equation explained

Drake’s equation was more of a guide for scientists on how to go about searching for life, rather than an estimating tool or serious attempt to determine an accurate result.

Its parameters included the rate of yearly star formation in the Milky Way, the fraction of stars with planets orbiting them and the number of worlds that could potentially support life.

By comparison, the new model connects the rate of yearly star formation in the universe with its fundamental ingredients, such as the aforementioned dark energy density.

View larger. | The Drake Equation, a mathematical formula for the probability of finding life or advanced civilizations in the universe, as revised by 2 University of Rochester researchers in 2016. Image via Royal Astronomical Society/ University of Rochester/ CC BY 4.0.

Bottom line: A team of astronomers recently looked at how different densities of dark matter in various possible universes would affect the chances for intelligent life. They found we might not even live in the best possible universe for forming life.

Source: The impact of the cosmological constant on past and future star formation

Via Royal Astronomical Society

The post Estimating the odds for intelligent life in the multiverse first appeared on EarthSky.

from EarthSky https://ift.tt/TQ0BKnz

This Hubble Space Telescope image captures a triple-star system, which can host potentially habitable planets. Our nearest stellar neighbor, the Alpha Centauri system, includes 3 stars. A team of astronomers recently estimated the chances for intelligent life in our universe and other possible universes. They did so by looking at how different densities of dark matter affect star formation. Image via NASA/ ESA/ G. Duchene (Universite de Grenoble I)/ Royal Astronomical Society. Image processing via Gladys Kober (NASA/Catholic University of America). CC BY 4.0.

• Intelligent life in the universe requires the existence of stars and worlds around stars, as far as we know.
• Stars form from clumps of matter, and this structure is possible thanks to a universe where dark energy makes the universe expand faster to balance gravity’s inward pull.
• Of all possible universes, a new study found that our universe might not even be the best possible universe for forming life.

The Royal Astronomical Society published this original story at 00:01 GMT on November 13, 2024. Edits by EarthSky.

Estimating the chances for intelligent life

The chances of intelligent life emerging in our universe – and in any hypothetical ones beyond it – is something astronomers have now estimated, using a new theoretical model with echoes of the famous Drake Equation. This was the formula that American astronomer Frank Drake came up with in the 1960s to calculate the number of detectable extraterrestrial civilizations in our Milky Way galaxy.

More than 60 years on, astrophysicists led by Durham University have produced a different model, which instead focuses on the conditions created by the acceleration of the universe’s expansion and the amount of stars formed.

It is thought this expansion is being driven by a mysterious force called dark energy that makes up more than 2/3s of the universe.

The peer-reviewed Monthly Notices of the Royal Astronomical Society published the study on November 13, 2024.

What is the calculation?

Stars are a precondition for the emergence of life as we know it. So the model could therefore be used to estimate the probability of generating intelligent life in our universe, and in a multiverse scenario of hypothetical different universes.

The new research does not attempt to calculate the absolute number of observers (i.e. intelligent life) in the universe. But instead it considers the relative probability of a randomly chosen observer inhabiting a universe with particular properties.

It concludes that a typical observer would expect to experience a substantially larger density of dark energy than we see in our own universe. And that suggests the ingredients our universe possesses make it a rare and unusual case in the multiverse.

The approach presented in the paper involves calculating the fraction of ordinary matter converted into stars over the entire history of the universe, for different dark-energy densities.

The model predicts this fraction would be approximately 27% in a universe that is most efficient at forming stars, compared to 23% in our own universe.

This means we don’t live in the hypothetical universe with the highest odds of forming intelligent lifeforms. Or in other words, the value of dark energy density we observe in our universe is not the one that would maximize the chances of life, according to the model.

Dark energy’s impact on our existence

Lead researcher Daniele Sorini, of Durham University’s Institute for Computational Cosmology, said:

Understanding dark energy and the impact on our universe is one of the biggest challenges in cosmology and fundamental physics.

The parameters that govern our universe, including the density of dark energy, could explain our own existence.

Surprisingly, though, we found that even a significantly higher dark energy density would still be compatible with life, suggesting we may not live in the most likely of universes.

The new model could allow scientists to understand the effects of differing densities of dark energy on the formation of structures in the universe and the conditions for life to develop in the cosmos.

The role of dark energy in intelligent life

Dark energy makes the universe expand faster, balancing gravity’s pull and creating a universe where both expansion and structure formation are possible.

However, for life to develop, there would need to be regions where matter can clump together to form stars and planets, and it would need to remain stable for billions of years to allow life to evolve.

Crucially, the research suggests that the astrophysics of star formation and the evolution of the large-scale structure of the universe combine in a subtle way to determine the optimal value of the dark energy density needed for the generation of intelligent life.

Lucas Lombriser, Université de Genève and co-author of the study, added:

It will be exciting to employ the model to explore the emergence of life across different universes and see whether some fundamental questions we ask ourselves about our own universe must be reinterpreted.

How the same region of the universe would look in terms of the amount of stars for different values of the dark energy density. Clockwise, from top left: no dark energy, same dark energy density as in our universe, 30 times the dark energy density in our universe and 10 times the dark energy density in our universe. The images are generated from a suite of cosmological simulations. Image via Oscar Veenema/ Royal Astronomical Society/ CC BY 4.0.

Drake Equation explained

Drake’s equation was more of a guide for scientists on how to go about searching for life, rather than an estimating tool or serious attempt to determine an accurate result.

Its parameters included the rate of yearly star formation in the Milky Way, the fraction of stars with planets orbiting them and the number of worlds that could potentially support life.

By comparison, the new model connects the rate of yearly star formation in the universe with its fundamental ingredients, such as the aforementioned dark energy density.

View larger. | The Drake Equation, a mathematical formula for the probability of finding life or advanced civilizations in the universe, as revised by 2 University of Rochester researchers in 2016. Image via Royal Astronomical Society/ University of Rochester/ CC BY 4.0.

Bottom line: A team of astronomers recently looked at how different densities of dark matter in various possible universes would affect the chances for intelligent life. They found we might not even live in the best possible universe for forming life.

Source: The impact of the cosmological constant on past and future star formation

Via Royal Astronomical Society

The post Estimating the odds for intelligent life in the multiverse first appeared on EarthSky.

from EarthSky https://ift.tt/TQ0BKnz

Uranus mysteries solved with Voyager data

NASA’s Voyager 2 captured this image of Uranus while flying by the ice giant in 1986. New research using data from the mission shows a solar wind event took place during the flyby, leading to a mystery about the planet’s magnetosphere that now may be solved. Image via NASA/ JPL-Caltech.

• When Voyager 2 flew past Uranus in 1986, it found that the planet’s magnetosphere wasn’t what scientists expected.
• The magnetosphere showed intense electron radiation belts but no source of energized particles to feed those active belts.
• Now scientists found that the solar wind was the culprit, with a rare event that temporarily changed the magnetosphere while Voyager 2 was making its observations.

NASA published this original story on November 11, 2024. Edits by EarthSky.

Mysteries at Uranus

When NASA’s Voyager 2 spacecraft flew by Uranus in 1986, it provided scientists’ first — and, so far, only — close glimpse of this strange, sideways-rotating outer planet. Alongside the discovery of new moons and rings, baffling new mysteries confronted scientists. The energized particles around the planet defied their understanding of how magnetic fields work to trap particle radiation. And so Uranus earned a reputation as an outlier in our solar system.

Now, new research analyzing the data collected during that flyby 38 years ago has found the source of that particular mystery is a cosmic coincidence: It turns out that in the days just before Voyager 2’s flyby, the planet had been affected by an unusual kind of space weather. This space weather event squashed the planet’s magnetic field, dramatically compressing Uranus’ magnetosphere.

Jamie Jasinski of NASA’s Jet Propulsion Laboratory in Southern California is the lead author of the new work published in Nature Astronomy on November 11, 2024. Jasinski said:

If Voyager 2 had arrived just a few days earlier, it would have observed a completely different magnetosphere at Uranus. The spacecraft saw Uranus in conditions that only occur about 4% of the time.

What’s a magnetosphere?

Magnetospheres serve as protective bubbles around planets (including Earth) with magnetic cores and magnetic fields. They shield worlds from jets of ionized gas — or plasma — that stream out from the sun in the solar wind. Learning more about how magnetospheres work is important for understanding our own planet. And it’s also important to understand worlds in seldom-visited corners of our solar system and beyond.

That’s why scientists were eager to study Uranus’ magnetosphere. And what they saw in the Voyager 2 data in 1986 flummoxed them. Inside the planet’s magnetosphere were electron radiation belts with an intensity second only to Jupiter’s notoriously brutal radiation belts. But there was apparently no source of energized particles to feed those active belts. In fact, the rest of Uranus’ magnetosphere was almost devoid of plasma.

The missing plasma also puzzled scientists because they knew that the five major Uranian moons in the magnetic bubble should have produced water ions, as icy moons around other outer planets do. They concluded that the moons must be inert with no ongoing activity.

View larger. | The first panel of this artist’s concept depicts how Uranus’s magnetosphere — its protective bubble — was behaving before the flyby of NASA’s Voyager 2. The second panel shows an unusual kind of solar weather was happening during the 1986 flyby, giving scientists a skewed view of the magnetosphere. Image via NASA/JPL-Caltech.

Solving the mystery at Uranus

So why didn’t we observe plasma? And what was happening to beef up the radiation belts? The new data analysis points to the solar wind. When plasma from the sun pounded and compressed the magnetosphere, it likely drove plasma out of the system. The solar wind event also would have briefly intensified the dynamics of the magnetosphere, which would have fed the belts by injecting electrons into them.

The findings could be good news for those five major moons of Uranus: Some of them might be geologically active after all. With an explanation for the temporarily missing plasma, researchers say it’s plausible that the moons actually may have been spewing ions into the surrounding bubble all along.

Planetary scientists are focusing on bolstering their knowledge about the mysterious Uranus system, which the National Academies’ 2023 Planetary Science and Astrobiology Decadal Survey prioritized as a target for a future NASA mission.

New studies of Uranus

JPL’s Linda Spilker was among the Voyager 2 mission scientists glued to the images and other data that flowed in during the Uranus flyby in 1986. She remembers the anticipation and excitement of the event, which changed how scientists thought about the Uranian system.

Spilker, who has returned to the iconic mission to lead its science team as project scientist, said:

The flyby was packed with surprises, and we were searching for an explanation of its unusual behavior. The magnetosphere Voyager 2 measured was only a snapshot in time. This new work explains some of the apparent contradictions, and it will change our view of Uranus once again.

Voyager 2, now in interstellar space, is almost 13 billion miles (21 billion km) from Earth.

Bottom line: A new analysis of data shows that when the Voyager 2 spacecraft flew past Uranus in 1986, it saw a skewed view of the planet’s magnetosphere because a large solar wind event had just buffeted Uranus.

Source: The anomalous state of Uranus’s magnetosphere during the Voyager 2 flyby

Via NASA/JPL-Caltech

Read more: Evidence for ocean on Uranus moon Miranda is a surprise

The post Uranus mysteries solved with Voyager data first appeared on EarthSky.

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NASA’s Voyager 2 captured this image of Uranus while flying by the ice giant in 1986. New research using data from the mission shows a solar wind event took place during the flyby, leading to a mystery about the planet’s magnetosphere that now may be solved. Image via NASA/ JPL-Caltech.

• When Voyager 2 flew past Uranus in 1986, it found that the planet’s magnetosphere wasn’t what scientists expected.
• The magnetosphere showed intense electron radiation belts but no source of energized particles to feed those active belts.
• Now scientists found that the solar wind was the culprit, with a rare event that temporarily changed the magnetosphere while Voyager 2 was making its observations.

NASA published this original story on November 11, 2024. Edits by EarthSky.

Mysteries at Uranus

When NASA’s Voyager 2 spacecraft flew by Uranus in 1986, it provided scientists’ first — and, so far, only — close glimpse of this strange, sideways-rotating outer planet. Alongside the discovery of new moons and rings, baffling new mysteries confronted scientists. The energized particles around the planet defied their understanding of how magnetic fields work to trap particle radiation. And so Uranus earned a reputation as an outlier in our solar system.

Now, new research analyzing the data collected during that flyby 38 years ago has found the source of that particular mystery is a cosmic coincidence: It turns out that in the days just before Voyager 2’s flyby, the planet had been affected by an unusual kind of space weather. This space weather event squashed the planet’s magnetic field, dramatically compressing Uranus’ magnetosphere.

Jamie Jasinski of NASA’s Jet Propulsion Laboratory in Southern California is the lead author of the new work published in Nature Astronomy on November 11, 2024. Jasinski said:

If Voyager 2 had arrived just a few days earlier, it would have observed a completely different magnetosphere at Uranus. The spacecraft saw Uranus in conditions that only occur about 4% of the time.

What’s a magnetosphere?

Magnetospheres serve as protective bubbles around planets (including Earth) with magnetic cores and magnetic fields. They shield worlds from jets of ionized gas — or plasma — that stream out from the sun in the solar wind. Learning more about how magnetospheres work is important for understanding our own planet. And it’s also important to understand worlds in seldom-visited corners of our solar system and beyond.

That’s why scientists were eager to study Uranus’ magnetosphere. And what they saw in the Voyager 2 data in 1986 flummoxed them. Inside the planet’s magnetosphere were electron radiation belts with an intensity second only to Jupiter’s notoriously brutal radiation belts. But there was apparently no source of energized particles to feed those active belts. In fact, the rest of Uranus’ magnetosphere was almost devoid of plasma.

The missing plasma also puzzled scientists because they knew that the five major Uranian moons in the magnetic bubble should have produced water ions, as icy moons around other outer planets do. They concluded that the moons must be inert with no ongoing activity.

View larger. | The first panel of this artist’s concept depicts how Uranus’s magnetosphere — its protective bubble — was behaving before the flyby of NASA’s Voyager 2. The second panel shows an unusual kind of solar weather was happening during the 1986 flyby, giving scientists a skewed view of the magnetosphere. Image via NASA/JPL-Caltech.

Solving the mystery at Uranus

So why didn’t we observe plasma? And what was happening to beef up the radiation belts? The new data analysis points to the solar wind. When plasma from the sun pounded and compressed the magnetosphere, it likely drove plasma out of the system. The solar wind event also would have briefly intensified the dynamics of the magnetosphere, which would have fed the belts by injecting electrons into them.

The findings could be good news for those five major moons of Uranus: Some of them might be geologically active after all. With an explanation for the temporarily missing plasma, researchers say it’s plausible that the moons actually may have been spewing ions into the surrounding bubble all along.

Planetary scientists are focusing on bolstering their knowledge about the mysterious Uranus system, which the National Academies’ 2023 Planetary Science and Astrobiology Decadal Survey prioritized as a target for a future NASA mission.

New studies of Uranus

JPL’s Linda Spilker was among the Voyager 2 mission scientists glued to the images and other data that flowed in during the Uranus flyby in 1986. She remembers the anticipation and excitement of the event, which changed how scientists thought about the Uranian system.

Spilker, who has returned to the iconic mission to lead its science team as project scientist, said:

The flyby was packed with surprises, and we were searching for an explanation of its unusual behavior. The magnetosphere Voyager 2 measured was only a snapshot in time. This new work explains some of the apparent contradictions, and it will change our view of Uranus once again.

Voyager 2, now in interstellar space, is almost 13 billion miles (21 billion km) from Earth.

Bottom line: A new analysis of data shows that when the Voyager 2 spacecraft flew past Uranus in 1986, it saw a skewed view of the planet’s magnetosphere because a large solar wind event had just buffeted Uranus.

Source: The anomalous state of Uranus’s magnetosphere during the Voyager 2 flyby

Via NASA/JPL-Caltech

Read more: Evidence for ocean on Uranus moon Miranda is a surprise

The post Uranus mysteries solved with Voyager data first appeared on EarthSky.

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New! Measure black holes with light echoes

In this artist’s concept, a black hole’s intense gravity distorts the light coming from the Milky Way galaxy, located behind it. This phenomenon is called gravitational lensing. It can cause light from a single source to reach an observer several times, like echoes of light. And researchers said last week they’ve come up with a technique to detect the light echoes caused by gravitational lensing, from the vicinity around black holes. This technique could help them measure black holes. Image via ESA/Hubble, Digitized Sky Survey, Nick Risinger (skysurvey.org), N. Bartmann.

The 2025 EarthSky Lunar Calendar is now available! Makes a great gift. Get yours today!

New method for measuring black holes

If you were to watch a light flashing behind a black hole, a single flash might appear to you to repeat several times, like an echo. Why? Because massive objects like black holes warp the fabric of spacetime. That means light rays from a single source can take multiple different curved paths around black holes. And so some should take longer than others to reach our eyes. A team of astrophysicists reported this month (November 7, 2024) that it has devised a technique for detecting and measuring these light echoes from the warped space around black holes. They said their new technique could help pierce the mystery of black holes, whose gravity is so powerful that light passing too close is forever captured.

Black holes don’t emit light. So scientists are always looking for innovative ways to measure black holes, and thereby learn more about them. This team says its new technique could help measure the size and rotation of black holes. Scholars from the Institute for Advanced Study in Princeton, New Jersey, led this new research. The peer-reviewed Astrophysical Journal Letters published the new work on November 7, 2024.

Due to the immense gravity around a black hole, light rays get pulled around it via various curved routes. This diagram shows that, after a single flash of light near a black hole, some light rays travel straight to the observer. Others make one or more loops around the black hole first. The ones that travel a more looped path would look to us as if they were coming to us from a slightly different part of the sky. Image via George N. Wong et al.

Gravitational lensing around black holes

Since the first evidence for Einstein’s theory of general relativity in the year 1919, we’ve understood that massive objects do literally bend spacetime. We’ve known since then that when a light ray passes by an object with a huge gravitational pull, the path of the light will bend as it follows the curvature of space.

In more recent decades, astronomers have identified massive objects in space – including massive galaxies and giant black holes – that act as lenses. Such an object magnifies and distorts a light source located at a greater distance. Astronomers call the intervening objects gravitational lenses.

What’s new here is the method for detecting and measuring light that’s forced to travel multiple routes around an intervening black hole. George N. Wong is the study’s lead author. He said:

That light circles around black holes, causing echoes, has been theorized for years. But such echoes have not yet been measured. Our method offers a blueprint for making these measurements, which could potentially revolutionize our understanding of black hole physics.

How did they do it?

The scientists said they found a way to separate the faint light of individual echoes from the stronger light coming directly from matter circling the black hole. Their method relies on comparing the results of two very distant telescopes. It uses one on Earth and one in space, in a process called very long baseline interferometry. Very long baseline interferometry was the technique used to produce the first ever images of a black hole in 2019. That study used not just two, but multiple ground-based telescopes spread widely across Earth.

The team tested their technique by simulating tens of thousands of instances of light traveling around the supermassive black hole M87*. It’s located 55 million light-years away at the center of the galaxy M87.

And eureka! They found their method was able to measure how long the echoing photons were delayed before reaching an observer.

This image, which the European Southern Observatory released on March 27, 2024, shows the supermassive black hole at the center of the Milky Way in polarized light. A similar method could be used to detect light that echoes around black holes. Image via EHT Collaboration/ ESO.

Improving how we measure black holes

Importantly, the length of this echo delay is determined by both the mass and rotation of the black hole. And that’s why this research could be great news for astrophysicists. Lia Medeiros, one of the study’s authors, explained:

This method will not only be able to confirm when light orbiting a black hole has been measured, but will also provide a new tool for measuring the black hole’s fundamental properties.

We do have methods to calculate the spin and mass of black holes, but they’re not entirely reliable. The accretion disk – the bright, spinning ring of material around the black hole – can interfere with these measurements. Being able to verify these values via light echo delays would give scientists far greater confidence when measuring the fundamental properties of black holes.

The echo detection method has not yet been tried outside simulations. But, according to the researchers, putting the plan into practice is well within current scientific capabilities.

Bottom line: Astronomers say they’ve developed a new method to detect light that echoes around black holes. It could help them measure black holes’ size and rotation.

Source: Measuring Black Hole Light Echoes with Very Long Baseline Interferometry

Via Institute for Advanced Study

Read more: What is gravitational lensing?

Read more: Milky Way’s black hole in new image

The post New! Measure black holes with light echoes first appeared on EarthSky.

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In this artist’s concept, a black hole’s intense gravity distorts the light coming from the Milky Way galaxy, located behind it. This phenomenon is called gravitational lensing. It can cause light from a single source to reach an observer several times, like echoes of light. And researchers said last week they’ve come up with a technique to detect the light echoes caused by gravitational lensing, from the vicinity around black holes. This technique could help them measure black holes. Image via ESA/Hubble, Digitized Sky Survey, Nick Risinger (skysurvey.org), N. Bartmann.

The 2025 EarthSky Lunar Calendar is now available! Makes a great gift. Get yours today!

New method for measuring black holes

If you were to watch a light flashing behind a black hole, a single flash might appear to you to repeat several times, like an echo. Why? Because massive objects like black holes warp the fabric of spacetime. That means light rays from a single source can take multiple different curved paths around black holes. And so some should take longer than others to reach our eyes. A team of astrophysicists reported this month (November 7, 2024) that it has devised a technique for detecting and measuring these light echoes from the warped space around black holes. They said their new technique could help pierce the mystery of black holes, whose gravity is so powerful that light passing too close is forever captured.

Black holes don’t emit light. So scientists are always looking for innovative ways to measure black holes, and thereby learn more about them. This team says its new technique could help measure the size and rotation of black holes. Scholars from the Institute for Advanced Study in Princeton, New Jersey, led this new research. The peer-reviewed Astrophysical Journal Letters published the new work on November 7, 2024.

Due to the immense gravity around a black hole, light rays get pulled around it via various curved routes. This diagram shows that, after a single flash of light near a black hole, some light rays travel straight to the observer. Others make one or more loops around the black hole first. The ones that travel a more looped path would look to us as if they were coming to us from a slightly different part of the sky. Image via George N. Wong et al.

Gravitational lensing around black holes

Since the first evidence for Einstein’s theory of general relativity in the year 1919, we’ve understood that massive objects do literally bend spacetime. We’ve known since then that when a light ray passes by an object with a huge gravitational pull, the path of the light will bend as it follows the curvature of space.

In more recent decades, astronomers have identified massive objects in space – including massive galaxies and giant black holes – that act as lenses. Such an object magnifies and distorts a light source located at a greater distance. Astronomers call the intervening objects gravitational lenses.

What’s new here is the method for detecting and measuring light that’s forced to travel multiple routes around an intervening black hole. George N. Wong is the study’s lead author. He said:

That light circles around black holes, causing echoes, has been theorized for years. But such echoes have not yet been measured. Our method offers a blueprint for making these measurements, which could potentially revolutionize our understanding of black hole physics.

How did they do it?

The scientists said they found a way to separate the faint light of individual echoes from the stronger light coming directly from matter circling the black hole. Their method relies on comparing the results of two very distant telescopes. It uses one on Earth and one in space, in a process called very long baseline interferometry. Very long baseline interferometry was the technique used to produce the first ever images of a black hole in 2019. That study used not just two, but multiple ground-based telescopes spread widely across Earth.

The team tested their technique by simulating tens of thousands of instances of light traveling around the supermassive black hole M87*. It’s located 55 million light-years away at the center of the galaxy M87.

And eureka! They found their method was able to measure how long the echoing photons were delayed before reaching an observer.

This image, which the European Southern Observatory released on March 27, 2024, shows the supermassive black hole at the center of the Milky Way in polarized light. A similar method could be used to detect light that echoes around black holes. Image via EHT Collaboration/ ESO.

Improving how we measure black holes

Importantly, the length of this echo delay is determined by both the mass and rotation of the black hole. And that’s why this research could be great news for astrophysicists. Lia Medeiros, one of the study’s authors, explained:

This method will not only be able to confirm when light orbiting a black hole has been measured, but will also provide a new tool for measuring the black hole’s fundamental properties.

We do have methods to calculate the spin and mass of black holes, but they’re not entirely reliable. The accretion disk – the bright, spinning ring of material around the black hole – can interfere with these measurements. Being able to verify these values via light echo delays would give scientists far greater confidence when measuring the fundamental properties of black holes.

The echo detection method has not yet been tried outside simulations. But, according to the researchers, putting the plan into practice is well within current scientific capabilities.

Bottom line: Astronomers say they’ve developed a new method to detect light that echoes around black holes. It could help them measure black holes’ size and rotation.

Source: Measuring Black Hole Light Echoes with Very Long Baseline Interferometry

Via Institute for Advanced Study

Read more: What is gravitational lensing?

Read more: Milky Way’s black hole in new image

The post New! Measure black holes with light echoes first appeared on EarthSky.

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Ancient outer solar system had a weak magnetic field

View larger. | Artist’s concept of the gas and dust in a newly-forming planetary system such as our own. Scientists knew that the embedded magnetic field helped form the inner solar system. Now, a new study shows that it also played a part in shaping the outer solar system as well. Image via NASA.

• Scientists believe an ancient magnetic field helped to form asteroids and planets in the inner solar system billions of years ago. But what about the outer solar system?
• New MIT-led research suggests the magnetic field in the outer reaches of the early solar system was weaker, but still strong enough to pull in gas and dust. This field might have helped shape the outer solar system, including the giant planets.
• Scientists base their claims on tiny grains from the asteroid Ryugu. Japan’s Hayabusa2 mission brought the samples back to Earth in late 2020.

The 2025 EarthSky Lunar Calendar makes a great gift. Get yours today!

How did the outer solar system form?

A new study led by the Massachusetts Institute of Technology (MIT) in Cambridge shows that a vast magnetic field extended throughout our solar system, as it was forming. The field was weaker in the outer region, but still strong enough to help form asteroids and even the gas and ice giant planets. The researchers said on November 6, 2024, that they found clues to this giant, ancient magnetic field in tiny grains from asteroid Ryugu. The Japanese Hayabusa 2 mission brought the samples back to Earth in 2020. Ryugu is believed to have formed on the outskirts of the early solar system before migrating in toward the asteroid belt, eventually settling into an orbit between Earth and Mars. So it’s a messenger from that part of space, providing clues to ancient forces shaping our solar system.

The outer magnetic field would have pulled gas and dust inward to form asteroids and perhaps even help form the giant planets Jupiter, Saturn, Uranus and Neptune. Benjamin Weiss at MIT said:

We’re showing that, everywhere we look now, there was some sort of magnetic field that was responsible for bringing mass to where the sun and planets were forming. That now applies to the outer solar system planets.

The researchers published their peer-reviewed results in the journal AGU Advances on November 6, 2024.

Asteroid grains shed light on the outer solar system's origins @MIT @theAGU https://t.co/1hC5hpror9

— Phys.org (@physorg_com) November 6, 2024

Analyzing grain samples from asteroid Ryugu

This outer magnetic field would have been very weak. As a comparison, the vast field would have been about 15 microtesla, while our own little Earth’s magnetic field today is around 50 microtesla.

The researchers studied asteroid grains from asteroid Ryugu for evidence of this ancient, weak magnetic field in the outer solar system. The research team, led by MIT, acquired several individual grains for study. Each one was tiny, only about 1 millimeter (0.04 inches) in size. Using a magnetometer, they measured each particle’s magnetization in terms of strength and direction. Then, they demagnetized each grain by using an alternating magnetic field. The process was kind of like rewinding a tape recorder. Lead author Elias Mansbach, formerly at MIT and now the University of Cambridge in the U.K., explained:

Like a tape recorder, we are slowly rewinding the sample’s magnetic record. We then look for consistent trends that tell us if it formed in a magnetic field.

Weak magnetic field in outer solar system

The analysis showed no clear signs of a preserved magnetic field. So did that mean there was no magnetic field present in the early outer solar system? Not necessarily. The magnetic field could have been very weak. The results placed an upper limit of 15 microtesla in intensity.

So, was there a magnetic field or not?

Asteroid Ryugu, as seen by the Hayabusa2 spacecraft on July 12, 2018. Image via JAXA Hayabusa2/ Wikimedia Commons (CC BY 4.0).

Further clues from meteorites

In addition, the researchers examined data from meteorites that had been studied previously. In particular, they looked at meteorites thought to have formed in the outer solar system, and known as ungrouped carbonaceous chondrites. Previously, scientists thought that they were not old enough to have formed before the solar nebula completely dissipated. But Mansbach and his team wanted to take another look. They found they were indeed older than previously estimated. So they did form in the outer reaches of the solar nebula, which became the outer solar system. And they were magnetic. Mansbach said:

We reanalyzed the ages of these samples and found they are closer to the start of the solar system than previously thought. We think these samples formed in this distal, outer region. And one of these samples does actually have a positive field detection of about 5 microtesla, which is consistent with an upper limit of 15 microtesla.

In other words, those meteorite samples fit within the upper magnetic field limit of the Ryugu samples. This implies that there was a weak magnetic field in the early formation of the outer solar system. And although weaker than the magnetic field closer in to the sun, it could still pull in enough gas and dust to form asteroids and even the giant planets. Weiss added:

When you’re further from the sun, a weak magnetic field goes a long way. It was predicted that it doesn’t need to be that strong out there, and that’s what we’re seeing.

Asteroid Bennu

Now, the research team want to examine samples from the asteroid Bennu, which resembles Ryugu. NASA’s OSIRIS-REx spacecraft brought those ones back to Earth in September 2023. Mansbach said:

Bennu looks a lot like Ryugu, and we’re eagerly awaiting first results from those samples.

Bottom line: A new study of grain samples from asteroid Ryugu shows that an ancient magnetic field helped form asteroids and planets the early outer solar system.

Source: Evidence for Magnetically-Driven Accretion in the Distal Solar System

Via MIT

Read more: Asteroid Ryugu harbors life’s building blocks

Read more: Japan’s Hayabusa2 lands on asteroid Ryugu

The post Ancient outer solar system had a weak magnetic field first appeared on EarthSky.

from EarthSky https://ift.tt/THPy7dg

View larger. | Artist’s concept of the gas and dust in a newly-forming planetary system such as our own. Scientists knew that the embedded magnetic field helped form the inner solar system. Now, a new study shows that it also played a part in shaping the outer solar system as well. Image via NASA.

• Scientists believe an ancient magnetic field helped to form asteroids and planets in the inner solar system billions of years ago. But what about the outer solar system?
• New MIT-led research suggests the magnetic field in the outer reaches of the early solar system was weaker, but still strong enough to pull in gas and dust. This field might have helped shape the outer solar system, including the giant planets.
• Scientists base their claims on tiny grains from the asteroid Ryugu. Japan’s Hayabusa2 mission brought the samples back to Earth in late 2020.

The 2025 EarthSky Lunar Calendar makes a great gift. Get yours today!

How did the outer solar system form?

A new study led by the Massachusetts Institute of Technology (MIT) in Cambridge shows that a vast magnetic field extended throughout our solar system, as it was forming. The field was weaker in the outer region, but still strong enough to help form asteroids and even the gas and ice giant planets. The researchers said on November 6, 2024, that they found clues to this giant, ancient magnetic field in tiny grains from asteroid Ryugu. The Japanese Hayabusa 2 mission brought the samples back to Earth in 2020. Ryugu is believed to have formed on the outskirts of the early solar system before migrating in toward the asteroid belt, eventually settling into an orbit between Earth and Mars. So it’s a messenger from that part of space, providing clues to ancient forces shaping our solar system.

The outer magnetic field would have pulled gas and dust inward to form asteroids and perhaps even help form the giant planets Jupiter, Saturn, Uranus and Neptune. Benjamin Weiss at MIT said:

We’re showing that, everywhere we look now, there was some sort of magnetic field that was responsible for bringing mass to where the sun and planets were forming. That now applies to the outer solar system planets.

The researchers published their peer-reviewed results in the journal AGU Advances on November 6, 2024.

Asteroid grains shed light on the outer solar system's origins @MIT @theAGU https://t.co/1hC5hpror9

— Phys.org (@physorg_com) November 6, 2024

Analyzing grain samples from asteroid Ryugu

This outer magnetic field would have been very weak. As a comparison, the vast field would have been about 15 microtesla, while our own little Earth’s magnetic field today is around 50 microtesla.

The researchers studied asteroid grains from asteroid Ryugu for evidence of this ancient, weak magnetic field in the outer solar system. The research team, led by MIT, acquired several individual grains for study. Each one was tiny, only about 1 millimeter (0.04 inches) in size. Using a magnetometer, they measured each particle’s magnetization in terms of strength and direction. Then, they demagnetized each grain by using an alternating magnetic field. The process was kind of like rewinding a tape recorder. Lead author Elias Mansbach, formerly at MIT and now the University of Cambridge in the U.K., explained:

Like a tape recorder, we are slowly rewinding the sample’s magnetic record. We then look for consistent trends that tell us if it formed in a magnetic field.

Weak magnetic field in outer solar system

The analysis showed no clear signs of a preserved magnetic field. So did that mean there was no magnetic field present in the early outer solar system? Not necessarily. The magnetic field could have been very weak. The results placed an upper limit of 15 microtesla in intensity.

So, was there a magnetic field or not?

Asteroid Ryugu, as seen by the Hayabusa2 spacecraft on July 12, 2018. Image via JAXA Hayabusa2/ Wikimedia Commons (CC BY 4.0).

Further clues from meteorites

In addition, the researchers examined data from meteorites that had been studied previously. In particular, they looked at meteorites thought to have formed in the outer solar system, and known as ungrouped carbonaceous chondrites. Previously, scientists thought that they were not old enough to have formed before the solar nebula completely dissipated. But Mansbach and his team wanted to take another look. They found they were indeed older than previously estimated. So they did form in the outer reaches of the solar nebula, which became the outer solar system. And they were magnetic. Mansbach said:

We reanalyzed the ages of these samples and found they are closer to the start of the solar system than previously thought. We think these samples formed in this distal, outer region. And one of these samples does actually have a positive field detection of about 5 microtesla, which is consistent with an upper limit of 15 microtesla.

In other words, those meteorite samples fit within the upper magnetic field limit of the Ryugu samples. This implies that there was a weak magnetic field in the early formation of the outer solar system. And although weaker than the magnetic field closer in to the sun, it could still pull in enough gas and dust to form asteroids and even the giant planets. Weiss added:

When you’re further from the sun, a weak magnetic field goes a long way. It was predicted that it doesn’t need to be that strong out there, and that’s what we’re seeing.

Asteroid Bennu

Now, the research team want to examine samples from the asteroid Bennu, which resembles Ryugu. NASA’s OSIRIS-REx spacecraft brought those ones back to Earth in September 2023. Mansbach said:

Bennu looks a lot like Ryugu, and we’re eagerly awaiting first results from those samples.

Bottom line: A new study of grain samples from asteroid Ryugu shows that an ancient magnetic field helped form asteroids and planets the early outer solar system.

Source: Evidence for Magnetically-Driven Accretion in the Distal Solar System

Via MIT

Read more: Asteroid Ryugu harbors life’s building blocks

Read more: Japan’s Hayabusa2 lands on asteroid Ryugu

The post Ancient outer solar system had a weak magnetic field first appeared on EarthSky.

from EarthSky https://ift.tt/THPy7dg

Sunflowers are pretty and helpful: Lifeform of the week

Image via Susanne Jutzeler/ Pexels.

Sunflowers aren’t just pretty, but they have many helpful uses. People plant sunflowers in places where there have been nuclear accidents to help the soil recover. Plus, all parts of the sunflower are beneficial. They can serve as both food and fuel. Sunflowers have a circadian rhythm that help them follow the sun. And if you think all sunflowers are yellow … Surprise! There are many different types and colors.

The 2025 EarthSky Lunar Calendar is now available! A unique and beautiful poster-sized calendar. Keep up with all phases of the moon every night of the year. Get yours today!

Meet the sunflower

There are about 70 species of sunflowers. Most of these species are robust plants, composed of leaves and stems with a rough texture. The leaves are located in alternate positions along the stem and have serrated edges.

The stems are straight and firm without branches, which allows them to reach a size that can exceed 10 feet (3 meters) in height. The tallest sunflower was from Germany and stood at an incredible height of 30 feet (9.2 meters).

And what about the head? If the sunflower is big, the head is too. Their dimensions can vary from 2 inches to more than 15 inches in diameter (5 cm to 40 cm). The center consists of hundreds of tiny tubular flowers, from which the pips (seeds) emerge. Large petals lie in groups of two rows around the head.

Sunflowers have straight and firm stems. The heads have petals in 2 rows and the seeds are in the center. Image via Jirasin Yossri/ Unsplash.

Are all sunflowers yellow?

In general, sunflowers have yellow petals and brown centers, but those aren’t the only colors they can have. There are sunflowers with orange, red, purple, pink and even white petals. Additionally, the center can be lighter or darker. Velvet Queen, Chianti and White Nite sunflowers are striking.

Not all sunflowers are yellow. This is a Chianti sunflower. Look at that red velvet color! Image via Rob Duval/ Wikipedia (CC BY-SA 3.0).

And, as if that were not enough, there are also varieties of sunflower that do not have the shape we’re familiar with. Look at this sunflower called Teddy Bear, a fluffy cultivar. It gets its name from its pompom shape, which has a fluffy and soft texture.

The Teddy Bear cultivar is totally different from what we are used to seeing. Image via Mike Peel/ Wikipedia (CC BY-SA 4.0).

Do sunflowers always follow the sun?

This is a heliotropic plant, meaning it can move its head and follow the sunlight from dawn to dusk. However, only the youngest flowers perform this movement. Once they reach maturity, they stare fixedly to the east. This position allows for quick warm-up in the morning and, as a result, increases visits from pollinators.

The young plants reorient themselves toward the east during the night in anticipation of the morning. The most curious thing is that they follow a circadian rhythm, synchronized by the sun, which continues if it’s cloudy or if the plants are moved to constant light. Also, young plants can regulate their circadian rhythm in response to artificial light, although resynchronization takes time.

Young sunflowers follow the path of the sun. But mature sunflowers stay fixed looking at the east. Image via Aaron Burden/ Unsplash.

What do sunflowers have to do with nuclear disasters?

Sunflowers have a life cycle of about three or four months, from the moment they germinate until farmers harvest them. They bloom in late spring or early summer. That’s why you see these flowers in abundance during the warmest months.

When sunflowers receive the necessary hours of sun per day – between six and eight hours – they grow strong and fast. And although sunflowers do not like sudden changes or frost, they are fairly resistant and can tolerate temperate and even slightly cold temperatures well. They also withstand drought and soils of varying acidity.

Plus, it’s amazing what their roots are capable of … They can eliminate heavy metals found in the soil, such as lead, arsenic and uranium. This is why people planted them near Chernobyl in 1986 and Fukushima in 2011 after the nuclear disasters.

Likewise, being a deep-rooted plant, they help break soil compaction and improve its structure. In addition, the sunflower is highly efficient at extracting nutrients, which reduces soil depletion and favors the cultivation of other plants in the following season.

When sunflowers receive around 6 or 8 hours of light, they grow strong and fast. Also, their roots are strong and help break soil compaction, favoring the cultivation of other plants in the following season. Image via Stefano Zocca/ Unsplash.

Uses of sunflowers

If helping us get back to normal after a nuclear accident doesn’t seem enough to you, know that our dear friends have many more uses.

Sunflowers’ main use is as food. Their seeds, or pips, are edible. They are covered by a dark layer with cream-colored lines that protect the seed. When temperatures are high, they dry out for harvesting.

You can simply peel and eat them, although usually they’re dried further or baked within their shells. They can also be toasted and salted, making for a delicious snack. Chefs also use the peeled seeds in breads, salads and many more dishes.

Another use for the sunflower seed is in making sunflower oil, which is rich in vitamin E. And sunflower oil has many uses, from cooking to soaps and cosmetics to biodiesel.

Likewise, the petals are useful in making wines or infusions. The stems contain a fiber used in making paper. And the rest of the plant is often used as animal feed.

We can benefit from all parts of this plant. We can eat the seeds as a snack, use them in salads, produce oil, biodiesel, cosmetics … and creatures such as pollinators and birds love them too! Image via Caio/ Pexels.

Where does this wonderful plant come from?

The sunflower is native to Central America. It is an old plant, already cultivated in the year 1000 BCE. In many cultures originating from the Americas, such as the indigenous people of Mexico (Aztecs and Otomi) and Peru (Incas, Chanka, Huanca and Chachapoyas), the sunflower was a representation of the solar deity. This plant represented prosperity and wealth. And they were right, because we’ve already seen the good these plants can do.

It was the Spaniards who brought sunflower seeds to Europe in the 16th century, and from there, they began to spread throughout the world. Since then, people have found many uses for them. Not to mention the number of artists who have used sunflowers as a source of inspiration. Have you seen the work of Vincent van Gogh or Claude Monet?

Maybe now that you know all these things about sunflowers you would like to plant them in your garden. You will also see them in a different way when you see entire fields of this showy, joyful and full-of-life plant.

Sunflowers not only serve as food or fuel, but they also eliminate heavy metals found in the soil, such as lead, arsenic and uranium. They were planted after nuclear disasters to help the land recover. These plants are full of life. Image via Jeb Buchman/ Unsplash.

Bottom line: Sunflowers are amazing. You can benefit from all their parts. They offer us food, oil and biodiesel and they even help the land recover after nuclear disasters.

Water lilies, beautiful and colorful: Lifeform of the week

Carnivorous plants are our lifeform of the week

The post Sunflowers are pretty and helpful: Lifeform of the week first appeared on EarthSky.

from EarthSky https://ift.tt/ay9xeIW

Image via Susanne Jutzeler/ Pexels.

Sunflowers aren’t just pretty, but they have many helpful uses. People plant sunflowers in places where there have been nuclear accidents to help the soil recover. Plus, all parts of the sunflower are beneficial. They can serve as both food and fuel. Sunflowers have a circadian rhythm that help them follow the sun. And if you think all sunflowers are yellow … Surprise! There are many different types and colors.

The 2025 EarthSky Lunar Calendar is now available! A unique and beautiful poster-sized calendar. Keep up with all phases of the moon every night of the year. Get yours today!

Meet the sunflower

There are about 70 species of sunflowers. Most of these species are robust plants, composed of leaves and stems with a rough texture. The leaves are located in alternate positions along the stem and have serrated edges.

The stems are straight and firm without branches, which allows them to reach a size that can exceed 10 feet (3 meters) in height. The tallest sunflower was from Germany and stood at an incredible height of 30 feet (9.2 meters).

And what about the head? If the sunflower is big, the head is too. Their dimensions can vary from 2 inches to more than 15 inches in diameter (5 cm to 40 cm). The center consists of hundreds of tiny tubular flowers, from which the pips (seeds) emerge. Large petals lie in groups of two rows around the head.

Sunflowers have straight and firm stems. The heads have petals in 2 rows and the seeds are in the center. Image via Jirasin Yossri/ Unsplash.

Are all sunflowers yellow?

In general, sunflowers have yellow petals and brown centers, but those aren’t the only colors they can have. There are sunflowers with orange, red, purple, pink and even white petals. Additionally, the center can be lighter or darker. Velvet Queen, Chianti and White Nite sunflowers are striking.

Not all sunflowers are yellow. This is a Chianti sunflower. Look at that red velvet color! Image via Rob Duval/ Wikipedia (CC BY-SA 3.0).

And, as if that were not enough, there are also varieties of sunflower that do not have the shape we’re familiar with. Look at this sunflower called Teddy Bear, a fluffy cultivar. It gets its name from its pompom shape, which has a fluffy and soft texture.

The Teddy Bear cultivar is totally different from what we are used to seeing. Image via Mike Peel/ Wikipedia (CC BY-SA 4.0).

Do sunflowers always follow the sun?

This is a heliotropic plant, meaning it can move its head and follow the sunlight from dawn to dusk. However, only the youngest flowers perform this movement. Once they reach maturity, they stare fixedly to the east. This position allows for quick warm-up in the morning and, as a result, increases visits from pollinators.

The young plants reorient themselves toward the east during the night in anticipation of the morning. The most curious thing is that they follow a circadian rhythm, synchronized by the sun, which continues if it’s cloudy or if the plants are moved to constant light. Also, young plants can regulate their circadian rhythm in response to artificial light, although resynchronization takes time.

Young sunflowers follow the path of the sun. But mature sunflowers stay fixed looking at the east. Image via Aaron Burden/ Unsplash.

What do sunflowers have to do with nuclear disasters?

Sunflowers have a life cycle of about three or four months, from the moment they germinate until farmers harvest them. They bloom in late spring or early summer. That’s why you see these flowers in abundance during the warmest months.

When sunflowers receive the necessary hours of sun per day – between six and eight hours – they grow strong and fast. And although sunflowers do not like sudden changes or frost, they are fairly resistant and can tolerate temperate and even slightly cold temperatures well. They also withstand drought and soils of varying acidity.

Plus, it’s amazing what their roots are capable of … They can eliminate heavy metals found in the soil, such as lead, arsenic and uranium. This is why people planted them near Chernobyl in 1986 and Fukushima in 2011 after the nuclear disasters.

Likewise, being a deep-rooted plant, they help break soil compaction and improve its structure. In addition, the sunflower is highly efficient at extracting nutrients, which reduces soil depletion and favors the cultivation of other plants in the following season.

When sunflowers receive around 6 or 8 hours of light, they grow strong and fast. Also, their roots are strong and help break soil compaction, favoring the cultivation of other plants in the following season. Image via Stefano Zocca/ Unsplash.

Uses of sunflowers

If helping us get back to normal after a nuclear accident doesn’t seem enough to you, know that our dear friends have many more uses.

Sunflowers’ main use is as food. Their seeds, or pips, are edible. They are covered by a dark layer with cream-colored lines that protect the seed. When temperatures are high, they dry out for harvesting.

You can simply peel and eat them, although usually they’re dried further or baked within their shells. They can also be toasted and salted, making for a delicious snack. Chefs also use the peeled seeds in breads, salads and many more dishes.

Another use for the sunflower seed is in making sunflower oil, which is rich in vitamin E. And sunflower oil has many uses, from cooking to soaps and cosmetics to biodiesel.

Likewise, the petals are useful in making wines or infusions. The stems contain a fiber used in making paper. And the rest of the plant is often used as animal feed.

We can benefit from all parts of this plant. We can eat the seeds as a snack, use them in salads, produce oil, biodiesel, cosmetics … and creatures such as pollinators and birds love them too! Image via Caio/ Pexels.

Where does this wonderful plant come from?

The sunflower is native to Central America. It is an old plant, already cultivated in the year 1000 BCE. In many cultures originating from the Americas, such as the indigenous people of Mexico (Aztecs and Otomi) and Peru (Incas, Chanka, Huanca and Chachapoyas), the sunflower was a representation of the solar deity. This plant represented prosperity and wealth. And they were right, because we’ve already seen the good these plants can do.

It was the Spaniards who brought sunflower seeds to Europe in the 16th century, and from there, they began to spread throughout the world. Since then, people have found many uses for them. Not to mention the number of artists who have used sunflowers as a source of inspiration. Have you seen the work of Vincent van Gogh or Claude Monet?

Maybe now that you know all these things about sunflowers you would like to plant them in your garden. You will also see them in a different way when you see entire fields of this showy, joyful and full-of-life plant.

Sunflowers not only serve as food or fuel, but they also eliminate heavy metals found in the soil, such as lead, arsenic and uranium. They were planted after nuclear disasters to help the land recover. These plants are full of life. Image via Jeb Buchman/ Unsplash.

Bottom line: Sunflowers are amazing. You can benefit from all their parts. They offer us food, oil and biodiesel and they even help the land recover after nuclear disasters.

Water lilies, beautiful and colorful: Lifeform of the week

Carnivorous plants are our lifeform of the week

The post Sunflowers are pretty and helpful: Lifeform of the week first appeared on EarthSky.

from EarthSky https://ift.tt/ay9xeIW

LIVE MONDAY: A Fermi Paradox solution with Alan Stern

Join us LIVE Monday, November 11, to hear planetary scientist Alan Stern – leader of the mighty New Horizons mission to Pluto and the outer solar system – discuss the Fermi Paradox. The livestream begins at 12:15 CST (18:15 UTC) on Monday, November 11, 2024. Find a ‘notify me’ button here.

Solving the Fermi Paradox with Alan Stern

There are several hundred billion stars in our Milky Way galaxy alone. And we think at least one planet orbits most of these stars, some of which are likely habitable by some form of life. So where is everyone? Where is the direct evidence of intelligent life? This is the Fermi Paradox. And – starting at 12:15 p.m. CST, or 18:15 UTC on Monday, November 11 – EarthSky’s popular YouTube presenter Will Triggs will be discussing the Fermi Paradox with renowned planetary scientist Alan Stern. Remember the New Horizons mission to Pluto in 2015? Alan is the person who conceived it and made it happen. Since then, his research into ocean worlds might help explain why we’ve not yet found any extraterrestrial neighbors.

We’ll also be talking with Alan about space exploration in our solar system. After exploring Pluto, New Horizons went on – and is still going on – exploring other objects in the Kuiper Belt in the outer solar system. New Horizons is now the 5th-farthest human-made object from Earth. Alan is now also serving as co-investigator for the Europa Clipper mission, which could provide some valuable data in relation to the Fermi Paradox when it arrives at Jupiter’s moon Europa in 2031. Once there, Europa Clipper will assess whether Jupiter’s moon could harbor alien life beneath its icy crust.

To top it all off, Alan recently became a civilian astronaut. He participated in a research spaceflight with Virgin Galactic in 2023, and is scheduled to fly again as a NASA researcher in 2026. There’s so much to discuss … come along and ask Alan a question!

The 2025 EarthSky Lunar Calendar is now available! A unique and beautiful poster-sized calendar. Keep up with all phases of the moon every night of the year. Get yours today!

Alan Stern served as NASA’s chief of all space and Earth science programs in 2007-8. He was named in the Time Magazine 100 list in both 2007 and 2016. And his latest research concerns the Fermi Paradox. Image via A. Stern.

Bottom line: Join us LIVE MONDAY (November 11, 2024) at 12:15 CST (18:15 UTC), when renowned planetary scientist Alan Stern will be discussing the Fermi Paradox with EarthSky’s Will Triggs.

The post LIVE MONDAY: A Fermi Paradox solution with Alan Stern first appeared on EarthSky.

from EarthSky https://ift.tt/lp8LzbO

Join us LIVE Monday, November 11, to hear planetary scientist Alan Stern – leader of the mighty New Horizons mission to Pluto and the outer solar system – discuss the Fermi Paradox. The livestream begins at 12:15 CST (18:15 UTC) on Monday, November 11, 2024. Find a ‘notify me’ button here.

Solving the Fermi Paradox with Alan Stern

There are several hundred billion stars in our Milky Way galaxy alone. And we think at least one planet orbits most of these stars, some of which are likely habitable by some form of life. So where is everyone? Where is the direct evidence of intelligent life? This is the Fermi Paradox. And – starting at 12:15 p.m. CST, or 18:15 UTC on Monday, November 11 – EarthSky’s popular YouTube presenter Will Triggs will be discussing the Fermi Paradox with renowned planetary scientist Alan Stern. Remember the New Horizons mission to Pluto in 2015? Alan is the person who conceived it and made it happen. Since then, his research into ocean worlds might help explain why we’ve not yet found any extraterrestrial neighbors.

We’ll also be talking with Alan about space exploration in our solar system. After exploring Pluto, New Horizons went on – and is still going on – exploring other objects in the Kuiper Belt in the outer solar system. New Horizons is now the 5th-farthest human-made object from Earth. Alan is now also serving as co-investigator for the Europa Clipper mission, which could provide some valuable data in relation to the Fermi Paradox when it arrives at Jupiter’s moon Europa in 2031. Once there, Europa Clipper will assess whether Jupiter’s moon could harbor alien life beneath its icy crust.

To top it all off, Alan recently became a civilian astronaut. He participated in a research spaceflight with Virgin Galactic in 2023, and is scheduled to fly again as a NASA researcher in 2026. There’s so much to discuss … come along and ask Alan a question!

The 2025 EarthSky Lunar Calendar is now available! A unique and beautiful poster-sized calendar. Keep up with all phases of the moon every night of the year. Get yours today!

Alan Stern served as NASA’s chief of all space and Earth science programs in 2007-8. He was named in the Time Magazine 100 list in both 2007 and 2016. And his latest research concerns the Fermi Paradox. Image via A. Stern.

Bottom line: Join us LIVE MONDAY (November 11, 2024) at 12:15 CST (18:15 UTC), when renowned planetary scientist Alan Stern will be discussing the Fermi Paradox with EarthSky’s Will Triggs.

The post LIVE MONDAY: A Fermi Paradox solution with Alan Stern first appeared on EarthSky.

from EarthSky https://ift.tt/lp8LzbO

Mirach is your guide star to finding 3 galaxies

Here is the Great Square of Pegasus, connected to the constellation Andromeda via the star Alpheratz. See Mirach? You can find the Andromeda galaxy (M31) – the large spiral galaxy next door to our Milky Way – by star-hopping with Mirach.

The 2025 EarthSky Lunar Calendar is now available! A unique and beautiful poster-sized calendar. Keep up with all phases of the moon every night of the year. Get yours today!

Mirach, also known as Beta Andromedae, is a moderately bright star in the constellation Andromeda. It’s a larger and more massive star than our sun. Mirach has about three to four times the sun’s mass and 100 times the sun’s diameter. It shines with about 1,900 times our sun’s total brightness. Mirach is what’s known as a red giant star, a star in the final stages of its evolution whose outer layers have expanded. But Mirach is rather far away at 200 light-years, and thus it shines in our sky at only 2nd magnitude, a respectable brightness but not as bright as that of many other stars.

Yet Mirach is an important star to stargazers. Amateur astronomers often use this star to guide them in locating three galaxies: the Andromeda galaxy (M31), the Triangulum galaxy (M33) and a galaxy known as Mirach’s Ghost (NGC 404).

The Andromeda galaxy is possible to spot with the unaided eye or binoculars on a dark moonless night sky. The other two galaxies are much fainter. You’ll likely need a telescope to see them.

Finding the Andromeda galaxy with Mirach

Draw an imaginary line from Mirach to the star Mu (µ) Andromedae. Then, continue extending that line for about the same distance between those two stars to reach the Andromeda Galaxy.

Under dark, moonless skies, the Andromeda galaxy appears as a smudge in the sky to the unaided eye. Even if the moon is out or under skies with moderate light pollution (like the suburbs), you can see it through binoculars. At about 2.5 million light-years away, the Andromeda galaxy is the nearest large spiral galaxy to our Milky Way. And it’s the most distant thing you can see with your eye alone.

A star map of the constellation Andromeda showing the locations of the Andromeda Galaxy (M31) and the Triangulum Galaxy (M33). Image via IAU.

Finding the Triangulum galaxy (M33)

The Triangulum Galaxy, in the constellation Triangulum, is much fainter than the Andromeda Galaxy. Some people with excellent eyesight have been able to see it, unaided by telescopes or binoculars, in extraordinarily good viewing conditions. Even so, it can still be a challenge to find M33 with binoculars and small telescopes.

To find Triangulum, you’ll use the same two stars as above but star-hop in the opposite direction. Follow an imaginary line from the star Mu (µ) Andromedae to Mirach, then continue to draw that line past Mirach, for twice the distance between Mu Andromedae and Mirach, to reach the Triangulum Galaxy.

Here are 2 of the 3 galaxies you can find via the star Mirach in the constellation Andromeda. M31 is easy to find on a dark night, from a rural location. M33 is tougher to spot. Chart via IAU.

Finding Mirach’s Ghost (NGC 404)

So when you look at Mirach, you’re looking almost exactly in the direction of the galaxy labeled NGC 404 but known affectionately among astronomers as Mirach’s Ghost. That’s because the remote, fuzzy galaxy lies right next to the moderately bright star, just 1/10 degree from Mirach. A full moon is 1/2 degree wide, so you can see that’s very close.

Mirach’s Ghost is faint, just magnitude 11 in brightness. Many amateur astronomers try to spot it with their small telescopes, but due to its proximity to the brighter 2nd-magnitude Mirach, seeing the galaxy is not easy.

NGC 404 is located about 10 million light-years away, just beyond our Local Group of galaxies. The Local Group is a cluster of galaxies that includes the Milky Way, Andromeda and Triangulum galaxies. NGC 404 does not appear gravitationally bound to our Local Group.

NGC 404, also known as Mirach’s Ghost, is the bluish-white object next to orange-colored Mirach. This image was taken by Tom Wildoner using a camera attached to a 4.7 inch (120 mm) refractor telescope. Image via Tom Wildoner. Used with permission.

Bottom line: Stargazers use Mirach, a moderately bright star in the constellation Andromeda, to locate three galaxies. It can help you find the Andromeda Galaxy, the Triangulum Galaxy and a galaxy known as Mirach’s Ghost (NGC 404).

The post Mirach is your guide star to finding 3 galaxies first appeared on EarthSky.

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Here is the Great Square of Pegasus, connected to the constellation Andromeda via the star Alpheratz. See Mirach? You can find the Andromeda galaxy (M31) – the large spiral galaxy next door to our Milky Way – by star-hopping with Mirach.

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Mirach, also known as Beta Andromedae, is a moderately bright star in the constellation Andromeda. It’s a larger and more massive star than our sun. Mirach has about three to four times the sun’s mass and 100 times the sun’s diameter. It shines with about 1,900 times our sun’s total brightness. Mirach is what’s known as a red giant star, a star in the final stages of its evolution whose outer layers have expanded. But Mirach is rather far away at 200 light-years, and thus it shines in our sky at only 2nd magnitude, a respectable brightness but not as bright as that of many other stars.

Yet Mirach is an important star to stargazers. Amateur astronomers often use this star to guide them in locating three galaxies: the Andromeda galaxy (M31), the Triangulum galaxy (M33) and a galaxy known as Mirach’s Ghost (NGC 404).

The Andromeda galaxy is possible to spot with the unaided eye or binoculars on a dark moonless night sky. The other two galaxies are much fainter. You’ll likely need a telescope to see them.

Finding the Andromeda galaxy with Mirach

Draw an imaginary line from Mirach to the star Mu (µ) Andromedae. Then, continue extending that line for about the same distance between those two stars to reach the Andromeda Galaxy.

Under dark, moonless skies, the Andromeda galaxy appears as a smudge in the sky to the unaided eye. Even if the moon is out or under skies with moderate light pollution (like the suburbs), you can see it through binoculars. At about 2.5 million light-years away, the Andromeda galaxy is the nearest large spiral galaxy to our Milky Way. And it’s the most distant thing you can see with your eye alone.

A star map of the constellation Andromeda showing the locations of the Andromeda Galaxy (M31) and the Triangulum Galaxy (M33). Image via IAU.

Finding the Triangulum galaxy (M33)

The Triangulum Galaxy, in the constellation Triangulum, is much fainter than the Andromeda Galaxy. Some people with excellent eyesight have been able to see it, unaided by telescopes or binoculars, in extraordinarily good viewing conditions. Even so, it can still be a challenge to find M33 with binoculars and small telescopes.

To find Triangulum, you’ll use the same two stars as above but star-hop in the opposite direction. Follow an imaginary line from the star Mu (µ) Andromedae to Mirach, then continue to draw that line past Mirach, for twice the distance between Mu Andromedae and Mirach, to reach the Triangulum Galaxy.

Here are 2 of the 3 galaxies you can find via the star Mirach in the constellation Andromeda. M31 is easy to find on a dark night, from a rural location. M33 is tougher to spot. Chart via IAU.

Finding Mirach’s Ghost (NGC 404)

So when you look at Mirach, you’re looking almost exactly in the direction of the galaxy labeled NGC 404 but known affectionately among astronomers as Mirach’s Ghost. That’s because the remote, fuzzy galaxy lies right next to the moderately bright star, just 1/10 degree from Mirach. A full moon is 1/2 degree wide, so you can see that’s very close.

Mirach’s Ghost is faint, just magnitude 11 in brightness. Many amateur astronomers try to spot it with their small telescopes, but due to its proximity to the brighter 2nd-magnitude Mirach, seeing the galaxy is not easy.

NGC 404 is located about 10 million light-years away, just beyond our Local Group of galaxies. The Local Group is a cluster of galaxies that includes the Milky Way, Andromeda and Triangulum galaxies. NGC 404 does not appear gravitationally bound to our Local Group.

NGC 404, also known as Mirach’s Ghost, is the bluish-white object next to orange-colored Mirach. This image was taken by Tom Wildoner using a camera attached to a 4.7 inch (120 mm) refractor telescope. Image via Tom Wildoner. Used with permission.

Bottom line: Stargazers use Mirach, a moderately bright star in the constellation Andromeda, to locate three galaxies. It can help you find the Andromeda Galaxy, the Triangulum Galaxy and a galaxy known as Mirach’s Ghost (NGC 404).

The post Mirach is your guide star to finding 3 galaxies first appeared on EarthSky.

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