Predicting lung cancer’s return at surgery

We need to stay one step ahead of cancer to treat it most effectively. And new research from scientists involved in our biggest investment in lung cancer to date – TRACERx led by our chief clinician Professor Charles Swanton  – could help us get there. The team has found clues in the blood that takes us one step closer to predicting the course the disease could take.

The new study, published in Nature Medicine,shows that if potential tumour cells are detected in the blood during surgery, it’s a good indicator that lung cancer will return.

It’s still early days, so far only 100 patient blood samples have been analysed. Professor Caroline Dive and her team from the Cancer Research UK Manchester Institute now hope to boost the sensitivity of the test, to make sure they reliably predict which cancers are more likely to come back.

And, as Dive explains, this information could help doctors get smarter about lung cancer treatment.

Identifying the culprits

But that’s not all they did. The team went into a little more detail in one person who had their blood sample collected at surgery. As well as mapping out the DNA profile of the lung tumour removed during surgery and the DNA profile of the tumour cells draining from the vein in the lung, they also looked into a second tumour that came back 10 months after treatment.

“The very interesting observation we made,” says Dive, “was that some of the tumour cells we found in the blood at surgery had a DNA profile that looked really, really similar to the DNA profile of the returning tumour.”

This suggests these were the cells that would go on to settle in another part of the body and start a new tumour.

“By looking at an individual patient who developed a secondary tumour 10 months after their surgery, we were able to trace the origin of the secondary tumour to particular cells that were escaping into the blood from the primary tumour at the time of surgery,” says Dive.

The team couldn’t, however, find matching cells in the first tumour, which suggests only a really small population of cells break off to grow elsewhere and are responsible for the tumour coming back (metastasis).

“I was surprised how such a small frequency was responsible,” said Dive. “But this is in one patient, we need to do lots more of this type of study to map where the dangerous cells are.”

Even though the findings need to be backed up using samples from more patients, Dive said what was really interesting is that even in the early stages of lung cancer, it looks like dangerous cells are already getting into the bloodstream.

“For many patients those cells that get into the bloodstream probably die and don’t cause trouble. But clearly there are some that do.” Dive says the big questions now is: can they identify the bad cells?

And if they can identify certain characteristics of tumour-seeding cancer cells in the blood, could they use this genetic information to tailor cancer treatment?

Clearly there are some big questions that need to be looked at further. But this early work has certainly put Dive and her team in a good position to out-manoeuvre lung cancer. 

“We’re really only at the beginning of this story and there’s a lot of work to do, but we’re already learning so much.”

Gabi

Read more on TRACERx:

Tracing genetic chaos in 100 lung cancer patients could help predict survival

Science Snaps: spotting lung cancers’ ‘crime hotspots’

The immune system preys on growing lung cancers, forcing them to evolve to survive

 

 

 

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

We need to stay one step ahead of cancer to treat it most effectively. And new research from scientists involved in our biggest investment in lung cancer to date – TRACERx led by our chief clinician Professor Charles Swanton  – could help us get there. The team has found clues in the blood that takes us one step closer to predicting the course the disease could take.

The new study, published in Nature Medicine,shows that if potential tumour cells are detected in the blood during surgery, it’s a good indicator that lung cancer will return.

It’s still early days, so far only 100 patient blood samples have been analysed. Professor Caroline Dive and her team from the Cancer Research UK Manchester Institute now hope to boost the sensitivity of the test, to make sure they reliably predict which cancers are more likely to come back.

And, as Dive explains, this information could help doctors get smarter about lung cancer treatment.

Identifying the culprits

But that’s not all they did. The team went into a little more detail in one person who had their blood sample collected at surgery. As well as mapping out the DNA profile of the lung tumour removed during surgery and the DNA profile of the tumour cells draining from the vein in the lung, they also looked into a second tumour that came back 10 months after treatment.

“The very interesting observation we made,” says Dive, “was that some of the tumour cells we found in the blood at surgery had a DNA profile that looked really, really similar to the DNA profile of the returning tumour.”

This suggests these were the cells that would go on to settle in another part of the body and start a new tumour.

“By looking at an individual patient who developed a secondary tumour 10 months after their surgery, we were able to trace the origin of the secondary tumour to particular cells that were escaping into the blood from the primary tumour at the time of surgery,” says Dive.

The team couldn’t, however, find matching cells in the first tumour, which suggests only a really small population of cells break off to grow elsewhere and are responsible for the tumour coming back (metastasis).

“I was surprised how such a small frequency was responsible,” said Dive. “But this is in one patient, we need to do lots more of this type of study to map where the dangerous cells are.”

Even though the findings need to be backed up using samples from more patients, Dive said what was really interesting is that even in the early stages of lung cancer, it looks like dangerous cells are already getting into the bloodstream.

“For many patients those cells that get into the bloodstream probably die and don’t cause trouble. But clearly there are some that do.” Dive says the big questions now is: can they identify the bad cells?

And if they can identify certain characteristics of tumour-seeding cancer cells in the blood, could they use this genetic information to tailor cancer treatment?

Clearly there are some big questions that need to be looked at further. But this early work has certainly put Dive and her team in a good position to out-manoeuvre lung cancer. 

“We’re really only at the beginning of this story and there’s a lot of work to do, but we’re already learning so much.”

Gabi

Read more on TRACERx:

Tracing genetic chaos in 100 lung cancer patients could help predict survival

Science Snaps: spotting lung cancers’ ‘crime hotspots’

The immune system preys on growing lung cancers, forcing them to evolve to survive

 

 

 

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

A year with 13 Friday the 13ths?

A month is based loosely on the cycle of the moon. Image via Tomruen/Wikimedia Commons.

Any calendar year has at least one Friday the 13th, and can have as many as three Friday the 13ths. This year, 2019, we have two: September 13 and December 13. However – should we ever choose to replace our standard Gregorian calendar with an International Fixed Calendar (more about it below) – we’d have 13 months in a single year, with each month featuring a Friday the 13th. That’d be 13 Friday the 13ths in one calendar year!

The month, of course, is an arbitrary concept, based loosely on the cycle of Earth’s companion moon. Months can be, and have been, many different lengths. In contrast to the Gregorian calendar, an International Fixed Calendar would be composed of 13 months, each of which would have 28 days (for a total of 364 days). With the International Fixed Calendar, weekday names would fall on the same dates each and every month. If your birthday was on a Monday one year, it’d be on a Monday every year. What this calendar system calls its Year Day would be a special day, existing outside of any week, inserted in between Saturday, December 28, and Sunday, January 1. Because Year Day would exist outside of any week or year, it’d be a holiday with no weekday name … to be celebrated as “a day out of time.”

Sound fun? Keep reading …

Of course, in a 13-month calendar system, we’d also have a new additional month. The International Fixed Calendar system calls this extra month Sol and requires that it fit between the months of June and July.

And what about leap years in the International Fixed Calendar? In a leap of year of 366 days, Leap Day would come one day after Saturday, June 28, and one day before Sunday, Sol 1. Like Year Day, Leap Day would reside outside of any week and therefore would have no weekday name.

Read more: Two Friday the 13ths in 2019

The lunar calendars are here! Get your 2020 lunar calendars today. They make great gifts. Going fast!

Every month in the 13-month calendar would harbor 28 days, with each month showcasing a Friday the 13th. Image via Wikipedia.

How likely are we to adopt the International Fixed Calendar? Not very likely. According to an article from CityLab.com:

Momentum behind the International Fixed Calendar, a 13-month calendar with 28 days in each month and a leftover day at the end of each year (it also followed the Gregorian rules with regards to Leap Years), was never stronger than in the late 1920s.

Similar to Auguste Comte’s positivist calendar (created in 1849), this particular 13-month invention came from the mind of Moses Cotsworth, a North Eastern Railway advisor bothered by inexplicably varying monthly earnings over the traditional 12-month period. Cotsworth’s plan quickly gained popularity among businessmen, especially in transportation and logistics. His biggest ally however, was photography pioneer and Kodak founder, George Eastman …

Read more from CityLab: The death and life of the 13-month calendar

The International Fixed Calendar of 13 months containing 28 days each. Note that all 13 months start on a Sunday and have a Friday the 13th. Illustration via CityLab.

Still, some people claim the 13-month calendar better synchronizes solar and lunar cycles, because the moon travels full circle in front of the constellations of the zodiac in about 27.3 days. (This 27.3-day period is known as the sidereal month.) Also, since the 28-day month corresponds to the mean length of the female menstrual cycle, the 13-month calendar is sometimes regarded as a feminine calendar.

On the other hand – still speaking of nature’s cycles here – the lunar (or synodic) month, which is based on the moon’s phases, lasts a solid two days longer than the 27.3-day sidereal month. The time period between successive full moons is about 29.5 days, which is about 1 1/2 days longer than the proposed 28-day calendar month.

So we’d lose our Blue Moons if we ever were to adopt the 13-month International Fixed Calendar. The second of two full moons in a single month is commonly called a Blue Moon. In this 13-month calendar, there wouldn’t be time in a single month for the moon to go from full, through all its phases, and back to full again.

But with this 13-month calendar, we’d certainly find calendar months having no full moon at all. In the 19-year Metonic cycle, we’d have 247 calendar months yet only 235 full moons, so somewhere around 12 calendar months would have no full moon in one 19-year period.

In our Gregorian calendar, only the month of February can have no full moon. This last happened in February 2018, and will next happen 19 years later, in February 2037.

Read more: Why no full moon in February 2018?

Now and again, I suppose, the International Fixed Calendar would actually find the full moon falling on Year Day or Leap Day, though I imagine quite rarely. Let me go out on the limb of modern folklore here and propose that a full moon happening outside of any week might be the International Fixed Calendar’s version of a Blue Moon!

The Gregorian dates between March and June are a day earlier during a Gregorian leap year. Image via Wikipedia.

Bottom line: The year 2019 presents a Friday the 13th in September and December. But should we ever switch over to the proposed 13-month calendar, we’d have a Friday the 13th every month.

from EarthSky https://ift.tt/30UlbHk

A month is based loosely on the cycle of the moon. Image via Tomruen/Wikimedia Commons.

Any calendar year has at least one Friday the 13th, and can have as many as three Friday the 13ths. This year, 2019, we have two: September 13 and December 13. However – should we ever choose to replace our standard Gregorian calendar with an International Fixed Calendar (more about it below) – we’d have 13 months in a single year, with each month featuring a Friday the 13th. That’d be 13 Friday the 13ths in one calendar year!

The month, of course, is an arbitrary concept, based loosely on the cycle of Earth’s companion moon. Months can be, and have been, many different lengths. In contrast to the Gregorian calendar, an International Fixed Calendar would be composed of 13 months, each of which would have 28 days (for a total of 364 days). With the International Fixed Calendar, weekday names would fall on the same dates each and every month. If your birthday was on a Monday one year, it’d be on a Monday every year. What this calendar system calls its Year Day would be a special day, existing outside of any week, inserted in between Saturday, December 28, and Sunday, January 1. Because Year Day would exist outside of any week or year, it’d be a holiday with no weekday name … to be celebrated as “a day out of time.”

Sound fun? Keep reading …

Of course, in a 13-month calendar system, we’d also have a new additional month. The International Fixed Calendar system calls this extra month Sol and requires that it fit between the months of June and July.

And what about leap years in the International Fixed Calendar? In a leap of year of 366 days, Leap Day would come one day after Saturday, June 28, and one day before Sunday, Sol 1. Like Year Day, Leap Day would reside outside of any week and therefore would have no weekday name.

Read more: Two Friday the 13ths in 2019

The lunar calendars are here! Get your 2020 lunar calendars today. They make great gifts. Going fast!

Every month in the 13-month calendar would harbor 28 days, with each month showcasing a Friday the 13th. Image via Wikipedia.

How likely are we to adopt the International Fixed Calendar? Not very likely. According to an article from CityLab.com:

Momentum behind the International Fixed Calendar, a 13-month calendar with 28 days in each month and a leftover day at the end of each year (it also followed the Gregorian rules with regards to Leap Years), was never stronger than in the late 1920s.

Similar to Auguste Comte’s positivist calendar (created in 1849), this particular 13-month invention came from the mind of Moses Cotsworth, a North Eastern Railway advisor bothered by inexplicably varying monthly earnings over the traditional 12-month period. Cotsworth’s plan quickly gained popularity among businessmen, especially in transportation and logistics. His biggest ally however, was photography pioneer and Kodak founder, George Eastman …

Read more from CityLab: The death and life of the 13-month calendar

The International Fixed Calendar of 13 months containing 28 days each. Note that all 13 months start on a Sunday and have a Friday the 13th. Illustration via CityLab.

Still, some people claim the 13-month calendar better synchronizes solar and lunar cycles, because the moon travels full circle in front of the constellations of the zodiac in about 27.3 days. (This 27.3-day period is known as the sidereal month.) Also, since the 28-day month corresponds to the mean length of the female menstrual cycle, the 13-month calendar is sometimes regarded as a feminine calendar.

On the other hand – still speaking of nature’s cycles here – the lunar (or synodic) month, which is based on the moon’s phases, lasts a solid two days longer than the 27.3-day sidereal month. The time period between successive full moons is about 29.5 days, which is about 1 1/2 days longer than the proposed 28-day calendar month.

So we’d lose our Blue Moons if we ever were to adopt the 13-month International Fixed Calendar. The second of two full moons in a single month is commonly called a Blue Moon. In this 13-month calendar, there wouldn’t be time in a single month for the moon to go from full, through all its phases, and back to full again.

But with this 13-month calendar, we’d certainly find calendar months having no full moon at all. In the 19-year Metonic cycle, we’d have 247 calendar months yet only 235 full moons, so somewhere around 12 calendar months would have no full moon in one 19-year period.

In our Gregorian calendar, only the month of February can have no full moon. This last happened in February 2018, and will next happen 19 years later, in February 2037.

Read more: Why no full moon in February 2018?

Now and again, I suppose, the International Fixed Calendar would actually find the full moon falling on Year Day or Leap Day, though I imagine quite rarely. Let me go out on the limb of modern folklore here and propose that a full moon happening outside of any week might be the International Fixed Calendar’s version of a Blue Moon!

The Gregorian dates between March and June are a day earlier during a Gregorian leap year. Image via Wikipedia.

Bottom line: The year 2019 presents a Friday the 13th in September and December. But should we ever switch over to the proposed 13-month calendar, we’d have a Friday the 13th every month.

from EarthSky https://ift.tt/30UlbHk

Watch for Draconid meteors in 2019

Image at top: Draconid meteor seen in 2011 by Frank Martin Ingilæ. Used with permission.

Draco the Dragon is now spitting out meteors, also known as shooting stars. This is one shower that’s best to watch at nightfall or early evening, not after midnight. No matter where you are on Earth, watch as close to nightfall as possible. The shower is active between October 6 and 10. The best evening to watch is likely October 8; try the evenings of October 7 and 9 also. This shower favors the Northern Hemisphere, but Southern Hemisphere observers might catch some Draconids, too. Unfortunately, the large bright evening moon will hinder this year’s Draconid shower. It’ll likely drown all but the brightest meteors in its glare.

Even at northerly latitudes, the Draconids are typically a very modest shower, offering only a handful of slow-moving meteors per hour. But exceptional displays have taken place over the years. The Draconid meteor shower produced awesome meteor displays in 1933 and 1946, with thousands of meteors per hour seen in those years. European observers saw over 600 meteors per hour in 2011.

Last year, in 2018, was also a favorable year because the new moon closely aligned with the peak date of the Draconids. But that’s not all. The Draconids’ parent comet – 21P/Giacobini-Zinner – reached perihelion, its closest point to the sun, in 2018, coming closer to Earth than it had in 72 years.

Those two facts added up to an outburst of Draconids for Europe in 2018. No outburst is expected this year. But meteor showers are notorious for defying the most carefully crafted forecasts. So you never know for sure what’s up in a meteor shower unless you look.

Read more: Spectacular Draconid meteor shower in 2018?

Read more: Find the radiant point for the Draconid meteor shower

Six-shot composite image of Draconid meteor shower – October 7, 2016 – by Steen Oervad of Denmark.

By the way, 21P/Giacobini-Zinner is a periodic comet, which returns near the sun every 6 years and 4 months. Tracking this comet, and noting this October meteor shower, helped astronomers figure out how to predict meteor showers in 1915.

For a taste of history related to this shower, go to the Astronomy Abstract Service from the Smithsonian and NASA and find a 1934 article called The Meteors from Giacobini’s Comet by C.C. Wylie.

It’s a fascinating account of the famed meteor storm of 1933.

Draconids radiate from near the Dragon’s Eyes: the stars Eltanin and Rastaban. Familiar with the Summer Triangle? Draw an imaginary line from Altair through Vega and it will point to them.

Here’s a more detailed view of the radiant point of the Draconid meteor shower. It’s highest in the north at nightfall in early October. That’s why this meteor shower is best in early evening – not after midnight – as seen from around the world.

Bottom line: In 2019, the Draconid meteor shower – also called the Giacobinids – will probably be at its best on the evening (not after midnight) of October 8. Try the evenings of October 7 and 9, too. A large bright evening moon moon is in the way for this shower; only the brightest meteors will be visible in its glare. By the way, there are more meteors ahead! Check out EarthSky’s 2019 meteor guide.

Donate: Your support means the world to us

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

Image at top: Draconid meteor seen in 2011 by Frank Martin Ingilæ. Used with permission.

Draco the Dragon is now spitting out meteors, also known as shooting stars. This is one shower that’s best to watch at nightfall or early evening, not after midnight. No matter where you are on Earth, watch as close to nightfall as possible. The shower is active between October 6 and 10. The best evening to watch is likely October 8; try the evenings of October 7 and 9 also. This shower favors the Northern Hemisphere, but Southern Hemisphere observers might catch some Draconids, too. Unfortunately, the large bright evening moon will hinder this year’s Draconid shower. It’ll likely drown all but the brightest meteors in its glare.

Even at northerly latitudes, the Draconids are typically a very modest shower, offering only a handful of slow-moving meteors per hour. But exceptional displays have taken place over the years. The Draconid meteor shower produced awesome meteor displays in 1933 and 1946, with thousands of meteors per hour seen in those years. European observers saw over 600 meteors per hour in 2011.

Last year, in 2018, was also a favorable year because the new moon closely aligned with the peak date of the Draconids. But that’s not all. The Draconids’ parent comet – 21P/Giacobini-Zinner – reached perihelion, its closest point to the sun, in 2018, coming closer to Earth than it had in 72 years.

Those two facts added up to an outburst of Draconids for Europe in 2018. No outburst is expected this year. But meteor showers are notorious for defying the most carefully crafted forecasts. So you never know for sure what’s up in a meteor shower unless you look.

Read more: Spectacular Draconid meteor shower in 2018?

Read more: Find the radiant point for the Draconid meteor shower

Six-shot composite image of Draconid meteor shower – October 7, 2016 – by Steen Oervad of Denmark.

By the way, 21P/Giacobini-Zinner is a periodic comet, which returns near the sun every 6 years and 4 months. Tracking this comet, and noting this October meteor shower, helped astronomers figure out how to predict meteor showers in 1915.

For a taste of history related to this shower, go to the Astronomy Abstract Service from the Smithsonian and NASA and find a 1934 article called The Meteors from Giacobini’s Comet by C.C. Wylie.

It’s a fascinating account of the famed meteor storm of 1933.

Draconids radiate from near the Dragon’s Eyes: the stars Eltanin and Rastaban. Familiar with the Summer Triangle? Draw an imaginary line from Altair through Vega and it will point to them.

Here’s a more detailed view of the radiant point of the Draconid meteor shower. It’s highest in the north at nightfall in early October. That’s why this meteor shower is best in early evening – not after midnight – as seen from around the world.

Bottom line: In 2019, the Draconid meteor shower – also called the Giacobinids – will probably be at its best on the evening (not after midnight) of October 8. Try the evenings of October 7 and 9, too. A large bright evening moon moon is in the way for this shower; only the brightest meteors will be visible in its glare. By the way, there are more meteors ahead! Check out EarthSky’s 2019 meteor guide.

Donate: Your support means the world to us

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

Not long ago, the center of our Milky Way galaxy exploded

Artist’s concept of the massive bursts of ionizing radiation exploding from the center of our Milky Way and impacting the Magellanic Stream. Image via James Josephides/ASTRO 3D.

Astronomers said today (October 6, 2019) that they’ve uncovered evidence for a titanic, expanding beam of energy that sprang from close to the supermassive black hole in the center of our Milky Way galaxy, just 3.5 million years ago. On Earth at that point, the asteroid that triggered the extinction of the dinosaurs was already 63 million years in the past, and humanity’s ancient ancestors, the australopithecines, were afoot in Africa. This explosion would have sent two enormous cone-shaped bursts of radiation through both poles of the galaxy and out into deep space. One burst must have been powerful enough to reach 200,000 light-years into space, so that its impact struck the Magellanic Stream, a long trail of gas extending from the nearby Large and Small Magellanic Clouds, dwarf galaxies orbiting our Milky Way.

Researchers estimate that the blast lasted for perhaps 300,000 years, a long time in human terms, but an extremely short time as measured on the scale of galaxies.

These new findings come from a team of scientists led by astronomer Joss Bland-Hawthorn from Australia’s ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D). They are soon to be published in the peer-reviewed Astrophysical Journal.

About 10% of all galaxies are known to have flares of this kind, which are called Seyfert flares. Our galaxy isn’t generally considered a Seyfert galaxy, or a particularly active galaxy at all. But the Milky Way is known to have a 4-million-solar-mass black hole at its heart, called Sagittarius A*, or Sgr A* (pronounced Sagittarius A-star). Even earlier this year, Sgr A* was caught having an unusually large meal of gas and dust.

So astronomers are learning that the Milky Way, too, can sometimes have a burst of activity.

The explosion 3.5 million years ago was too huge to have been triggered by anything other than nuclear activity associated with Sgr A*, said the team who studied it. Bland-Hawthorn commented:

The flare must have been a bit like a lighthouse beam. Imagine darkness, and then someone switches on a lighthouse beacon for a brief period of time.

Lisa Kewley, director of ASTRO 3D, said:

This is a dramatic event that happened a few million years ago in the Milky Way’s history. A massive blast of energy and radiation came right out of the galactic center and into the surrounding material. This shows that the center of the Milky Way is a much more dynamic place than we had previously thought. It is lucky we’re not residing there!

The lunar calendars are here! Get your 2020 lunar calendars today. They make great gifts. Going fast!

A schematic diagram showing the ionizing radiation field over the south galactic hemisphere of the Milky Way, disrupted by the Seyfert flare event. Image via Bland-Hawthorne, et al./ASTRO 3D.

Bottom line: Researchers have found evidence of a cataclysmic flare that punched outward in both directions from our galaxy’s center, reaching so far into intergalactic space that its impact was felt 200,000 light-years away.

Source (to be published in ApJ): The Large-Scale Ionisation Cones In The Galaxy

Via ScienceinPublic

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

Artist’s concept of the massive bursts of ionizing radiation exploding from the center of our Milky Way and impacting the Magellanic Stream. Image via James Josephides/ASTRO 3D.

Astronomers said today (October 6, 2019) that they’ve uncovered evidence for a titanic, expanding beam of energy that sprang from close to the supermassive black hole in the center of our Milky Way galaxy, just 3.5 million years ago. On Earth at that point, the asteroid that triggered the extinction of the dinosaurs was already 63 million years in the past, and humanity’s ancient ancestors, the australopithecines, were afoot in Africa. This explosion would have sent two enormous cone-shaped bursts of radiation through both poles of the galaxy and out into deep space. One burst must have been powerful enough to reach 200,000 light-years into space, so that its impact struck the Magellanic Stream, a long trail of gas extending from the nearby Large and Small Magellanic Clouds, dwarf galaxies orbiting our Milky Way.

Researchers estimate that the blast lasted for perhaps 300,000 years, a long time in human terms, but an extremely short time as measured on the scale of galaxies.

These new findings come from a team of scientists led by astronomer Joss Bland-Hawthorn from Australia’s ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D). They are soon to be published in the peer-reviewed Astrophysical Journal.

About 10% of all galaxies are known to have flares of this kind, which are called Seyfert flares. Our galaxy isn’t generally considered a Seyfert galaxy, or a particularly active galaxy at all. But the Milky Way is known to have a 4-million-solar-mass black hole at its heart, called Sagittarius A*, or Sgr A* (pronounced Sagittarius A-star). Even earlier this year, Sgr A* was caught having an unusually large meal of gas and dust.

So astronomers are learning that the Milky Way, too, can sometimes have a burst of activity.

The explosion 3.5 million years ago was too huge to have been triggered by anything other than nuclear activity associated with Sgr A*, said the team who studied it. Bland-Hawthorn commented:

The flare must have been a bit like a lighthouse beam. Imagine darkness, and then someone switches on a lighthouse beacon for a brief period of time.

Lisa Kewley, director of ASTRO 3D, said:

This is a dramatic event that happened a few million years ago in the Milky Way’s history. A massive blast of energy and radiation came right out of the galactic center and into the surrounding material. This shows that the center of the Milky Way is a much more dynamic place than we had previously thought. It is lucky we’re not residing there!

The lunar calendars are here! Get your 2020 lunar calendars today. They make great gifts. Going fast!

A schematic diagram showing the ionizing radiation field over the south galactic hemisphere of the Milky Way, disrupted by the Seyfert flare event. Image via Bland-Hawthorne, et al./ASTRO 3D.

Bottom line: Researchers have found evidence of a cataclysmic flare that punched outward in both directions from our galaxy’s center, reaching so far into intergalactic space that its impact was felt 200,000 light-years away.

Source (to be published in ApJ): The Large-Scale Ionisation Cones In The Galaxy

Via ScienceinPublic

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

The violent history of Andromeda, the big galaxy next door

Navaneeth Unnikrishnan of Kerala, India, created this wonderful stacked image of the Andromeda galaxy with images taken in 2014.

Standing outside on a clear night, in a dark country location, you can look across vast space to see the Andromeda galaxy, aka M31 – the large spiral galaxy next door to our Milky Way – the most distant thing we humans can see with the eye alone. This huge galaxy is twice the diameter of our Milky Way at about 200,000 light-years. It contains about a trillion stars, in contrast to the Milky Way’s 250-400 billion. To the eye, it looks peaceful, but, as astronomers have studied it, they’ve uncovered a violent past and future. For example, on October 1, 2019, astronomers announced evidence for two major “migration events” in the history of the Andromeda galaxy, that is, events where smaller dwarf galaxies merged with the larger galaxy. The more recent one happened a few billion years ago and the older event many billions of years before that.

The evidence for the two events comes from the relatively new field of galactic archaeology, that is, the use of the motions and properties of stars and star clusters – in this case, globular star clusters – to reconstruct a galaxy’s history. A statement from Gemini Observatory explained:

Gas and dwarf galaxies in the vast cosmic web follow the gravitational paths laid out by dark matter — traversing filaments, they migrate slowly toward collections of dark matter and assemble into large galaxies. As dwarf galaxies are pulled in by gravity, they are also pulled apart, leaving behind long trailing streams of stars and compact star clusters.

Astronomers study the leftover streams of stars – still visible in modern galaxies – to unearth a galaxy’s history. In this case, the astronomers analyzed data from the Pan-Andromeda Archaeological Survey, known as PAndAS. Their study was published in the peer-reviewed journal Nature on October 2. Australian National University researcher Dougal Mackey co-led the study with Geraint Lewis from the University of Sydney Lewis commented:

We are cosmic archaeologists, except we are digging through the fossils of long-dead galaxies rather than human history.

Dougal Mackey said:

By tracing the faint remains of these smaller galaxies with embedded star clusters, we’ve been able to recreate the way Andromeda drew them in and ultimately enveloped them at the different times.

The lunar calendars are here! Get your 2020 lunar calendars today. They make great gifts. Going fast!

View larger. | Here is part of the evidence for 2 ancient migration events in the Andromeda galaxy. Astronomers studied this galaxy’s globular star clusters (lower right insets), indicated by colored circles. They are located in the outer halo of the Andromeda Galaxy, beyond the bright disk of the galaxy (upper left inset). The clusters separate into 2 groups: one associated with stellar streams and one not associated with stellar streams. The orbits of these groups of globular clusters are very different from each other, a result that points to 2 separate migration events in the history of the galaxy. The color of each circle indicates the line-of-sight velocity of the corresponding star cluster. Image via Australian National University/NSF’s National Optical-Infrared Astronomy Research Laboratory/Gemini Observatory.

The discovery presents several new mysteries, with the two bouts of galactic feeding coming from completely different directions. Lewis said:

This is very weird and suggests that the extragalactic meals are fed from what’s known as the ‘cosmic web’ of matter that threads the universe.

More surprising is the discovery that the direction of the ancient feeding is the same as the bizarre ‘plane of satellites’, an unexpected alignment of dwarf galaxies orbiting Andromeda.

Mackey and Lewis were part of a team that previously discovered such planes were fragile and rapidly destroyed by Andromeda’s gravity within a few billion years. Lewis said:

This deepens the mystery as the plane must be young, but it appears to be aligned with ancient feeding of dwarf galaxies. Maybe this is because of the cosmic web, but really, this is only speculation.

We’re going to have to think quite hard to unravel what this is telling us.

These astronomers also spoke of the future of the Andromeda galaxy and our Milky Way. The two large galaxies are currently approaching each other, and they are expected yo collide several billion years from now. Mackey said:

The Milky Way is on a collision course with Andromeda in about four billion years. So knowing what kind of a monster our galaxy is up against is useful in finding out the Milky Way’s ultimate fate.

Artist’s concept of Earth’s night sky in 3.75 billion years. The Andromeda galaxy (left) will fill our field of view then, astronomers say, as it heads toward a collision, or merger, with our Milky way galaxy. Image via NASA/ESA/Z. Levay and R. van der Marel, STScI/T. Hallas; and A. Mellinger. Read more about the eventual merger of the Milky Way and Andromeda galaxies.

Bottom line: Astronomers used galactic archaeology – the study of star motions in a modern galaxy – to uncover past mergings of small galaxies with the Andromeda galaxy. They say this work will help them understand a collision due to occur between the Andromeda galaxy and our Milky Way, billions of years from now.

Source: Two major accretion epochs in M31 from two distinct populations of globular clusters

Via Australian National University

Via Gemini Observatory

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

Navaneeth Unnikrishnan of Kerala, India, created this wonderful stacked image of the Andromeda galaxy with images taken in 2014.

Standing outside on a clear night, in a dark country location, you can look across vast space to see the Andromeda galaxy, aka M31 – the large spiral galaxy next door to our Milky Way – the most distant thing we humans can see with the eye alone. This huge galaxy is twice the diameter of our Milky Way at about 200,000 light-years. It contains about a trillion stars, in contrast to the Milky Way’s 250-400 billion. To the eye, it looks peaceful, but, as astronomers have studied it, they’ve uncovered a violent past and future. For example, on October 1, 2019, astronomers announced evidence for two major “migration events” in the history of the Andromeda galaxy, that is, events where smaller dwarf galaxies merged with the larger galaxy. The more recent one happened a few billion years ago and the older event many billions of years before that.

The evidence for the two events comes from the relatively new field of galactic archaeology, that is, the use of the motions and properties of stars and star clusters – in this case, globular star clusters – to reconstruct a galaxy’s history. A statement from Gemini Observatory explained:

Gas and dwarf galaxies in the vast cosmic web follow the gravitational paths laid out by dark matter — traversing filaments, they migrate slowly toward collections of dark matter and assemble into large galaxies. As dwarf galaxies are pulled in by gravity, they are also pulled apart, leaving behind long trailing streams of stars and compact star clusters.

Astronomers study the leftover streams of stars – still visible in modern galaxies – to unearth a galaxy’s history. In this case, the astronomers analyzed data from the Pan-Andromeda Archaeological Survey, known as PAndAS. Their study was published in the peer-reviewed journal Nature on October 2. Australian National University researcher Dougal Mackey co-led the study with Geraint Lewis from the University of Sydney Lewis commented:

We are cosmic archaeologists, except we are digging through the fossils of long-dead galaxies rather than human history.

Dougal Mackey said:

By tracing the faint remains of these smaller galaxies with embedded star clusters, we’ve been able to recreate the way Andromeda drew them in and ultimately enveloped them at the different times.

The lunar calendars are here! Get your 2020 lunar calendars today. They make great gifts. Going fast!

View larger. | Here is part of the evidence for 2 ancient migration events in the Andromeda galaxy. Astronomers studied this galaxy’s globular star clusters (lower right insets), indicated by colored circles. They are located in the outer halo of the Andromeda Galaxy, beyond the bright disk of the galaxy (upper left inset). The clusters separate into 2 groups: one associated with stellar streams and one not associated with stellar streams. The orbits of these groups of globular clusters are very different from each other, a result that points to 2 separate migration events in the history of the galaxy. The color of each circle indicates the line-of-sight velocity of the corresponding star cluster. Image via Australian National University/NSF’s National Optical-Infrared Astronomy Research Laboratory/Gemini Observatory.

The discovery presents several new mysteries, with the two bouts of galactic feeding coming from completely different directions. Lewis said:

This is very weird and suggests that the extragalactic meals are fed from what’s known as the ‘cosmic web’ of matter that threads the universe.

More surprising is the discovery that the direction of the ancient feeding is the same as the bizarre ‘plane of satellites’, an unexpected alignment of dwarf galaxies orbiting Andromeda.

Mackey and Lewis were part of a team that previously discovered such planes were fragile and rapidly destroyed by Andromeda’s gravity within a few billion years. Lewis said:

This deepens the mystery as the plane must be young, but it appears to be aligned with ancient feeding of dwarf galaxies. Maybe this is because of the cosmic web, but really, this is only speculation.

We’re going to have to think quite hard to unravel what this is telling us.

These astronomers also spoke of the future of the Andromeda galaxy and our Milky Way. The two large galaxies are currently approaching each other, and they are expected yo collide several billion years from now. Mackey said:

The Milky Way is on a collision course with Andromeda in about four billion years. So knowing what kind of a monster our galaxy is up against is useful in finding out the Milky Way’s ultimate fate.

Artist’s concept of Earth’s night sky in 3.75 billion years. The Andromeda galaxy (left) will fill our field of view then, astronomers say, as it heads toward a collision, or merger, with our Milky way galaxy. Image via NASA/ESA/Z. Levay and R. van der Marel, STScI/T. Hallas; and A. Mellinger. Read more about the eventual merger of the Milky Way and Andromeda galaxies.

Bottom line: Astronomers used galactic archaeology – the study of star motions in a modern galaxy – to uncover past mergings of small galaxies with the Andromeda galaxy. They say this work will help them understand a collision due to occur between the Andromeda galaxy and our Milky Way, billions of years from now.

Source: Two major accretion epochs in M31 from two distinct populations of globular clusters

Via Australian National University

Via Gemini Observatory

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

Cosmic web fuels stars and supermassive black holes

Astronomers now think of our universe as a cosmic web, composed of massive filaments of galaxies separated by giant voids. We don’t know in detail what this cosmic web is like. Most of our exploration of it has come via computer models, in particular the cold dark matter model for galaxy formation, the model currently favored by most cosmologists. The model shows that filaments in the cosmic web – essentially long threads of gas – provide the fuel for the intense formation of stars and supermassive black holes. On October 4, 2019, astronomers said they’ve now obtained images of a particularly bright portion of the cosmic web, including threads of gas extending over 3 million light-years. They say it’s the first time the cosmic web has been imaged in such detail on that large a scale. And behold, the observations agree with what has been theorized. The region where these enormous filaments meet is home to an “exceptional number,” they said, of supermassive black holes and starbursting galaxies with very active star formation.

According to current theories of galaxy formation, such intense activity can only be triggered and sustained over time if large amounts of gas are funneled into the assembling cluster from the surrounding regions.

The group found that the detected filaments in the cosmic web contained a significant reservoir of gas. This gas, they expect, is what helps fuel the continued growth of galaxies in this region.

These astronomers are from the RIKEN Cluster for Pioneering Research in Japan and Durham University in the UK. They have a new paper out, published in the journal Science. An introduction to their paper explains:

Most gas in the universe lies in the intergalactic medium [between the galaxies], where it forms into sheets and filaments of the cosmic web. Clusters of galaxies form at the intersection of these filaments, fed by gas pulled along them by gravity. Although this picture is well established by cosmological simulations, it has been difficult to demonstrate observationally.

The lunar calendars are here! Get your 2020 lunar calendars today. They make great gifts. Going fast!

A massive galaxy cluster from the C-EAGLE simulation, run out of Durham University. This image provides a view of a region of our universe comparable to the one where astronomers have now detected filaments of gas. In this color map – constructed via sophisticated computer modeling – you’re seeing the same emission from gas filaments as the one now detected in observations. At the convergence of these filaments, a massive cluster of galaxies is assembling. Image via Joshua Borrow using C-EAGLE.

The new research was carried out using observations from the Multi Unit Spectroscopic Explorer (MUSE) at the European Southern Observatory’s Very Large Telescope. Their statement explained:

The astronomers detected the filaments of gas using the characteristic radiation produced when the neutral hydrogen gas they contain is excited by surrounding ultraviolet light and then returns to its lowest state of energy.

The detected radiation was too intense to originate only from the typical background level of ultraviolet light that permeates the universe, and the researchers’ models instead suggest that it is driven by the light emitted from the many star-forming galaxies and black holes in the region.

Lead author Hideki Umehata, of the RIKEN Cluster for Pioneering Research and the University of Tokyo, said:

The presence of such intense radiation suggests very strongly that gas falling along the filaments under the force of gravity triggers the formation of many starbursting galaxies and supermassive black holes, ultimately giving the universe the structure that we see today.

Previous observations have shown similar emission from blobs of gas extending beyond galaxies, but now we have been able to clearly show that these filaments stretch to much larger distances, going even beyond the edge of the field that we viewed.

This adds credence to the idea that these filaments are actually powering the intense activity that we see in galaxies within large structures assembling in the early universe.

Astronomers believe the early universe was nearly uniform as it expanded outward from the Big Bang. By a few billion years after the Big Bang, areas of slightly higher density had evolved to become galaxy clusters and groups, with sparsely populated regions devoid of galaxies in between. The universe as a whole evolved to this honeycomb-like structure, sometimes called the “cosmic web.” In this artist’s illustration, Mpc/h is a unit of distance, with 1 Mpc/h more than 3.2 million light-years. Image via Volker Springel, Virgo Consortium.

Bottom line: Astronomers in the U.K. and Japan probed the cosmic web, a large-scale structure composed of massive filaments of galaxies separated by giant voids. They found the filaments also contained significant amounts of gas, believed to help fuel the galaxies’ growth. The new observations give scientists a way to map the cosmic web directly and to understand in detail its role in regulating the formation of supermassive black holes and galaxies.

Source: Gas filaments of the cosmic web located around active galaxies in a protocluster

Via Durham University

from EarthSky https://ift.tt/2Mo5cfw

Astronomers now think of our universe as a cosmic web, composed of massive filaments of galaxies separated by giant voids. We don’t know in detail what this cosmic web is like. Most of our exploration of it has come via computer models, in particular the cold dark matter model for galaxy formation, the model currently favored by most cosmologists. The model shows that filaments in the cosmic web – essentially long threads of gas – provide the fuel for the intense formation of stars and supermassive black holes. On October 4, 2019, astronomers said they’ve now obtained images of a particularly bright portion of the cosmic web, including threads of gas extending over 3 million light-years. They say it’s the first time the cosmic web has been imaged in such detail on that large a scale. And behold, the observations agree with what has been theorized. The region where these enormous filaments meet is home to an “exceptional number,” they said, of supermassive black holes and starbursting galaxies with very active star formation.

According to current theories of galaxy formation, such intense activity can only be triggered and sustained over time if large amounts of gas are funneled into the assembling cluster from the surrounding regions.

The group found that the detected filaments in the cosmic web contained a significant reservoir of gas. This gas, they expect, is what helps fuel the continued growth of galaxies in this region.

These astronomers are from the RIKEN Cluster for Pioneering Research in Japan and Durham University in the UK. They have a new paper out, published in the journal Science. An introduction to their paper explains:

Most gas in the universe lies in the intergalactic medium [between the galaxies], where it forms into sheets and filaments of the cosmic web. Clusters of galaxies form at the intersection of these filaments, fed by gas pulled along them by gravity. Although this picture is well established by cosmological simulations, it has been difficult to demonstrate observationally.

The lunar calendars are here! Get your 2020 lunar calendars today. They make great gifts. Going fast!

A massive galaxy cluster from the C-EAGLE simulation, run out of Durham University. This image provides a view of a region of our universe comparable to the one where astronomers have now detected filaments of gas. In this color map – constructed via sophisticated computer modeling – you’re seeing the same emission from gas filaments as the one now detected in observations. At the convergence of these filaments, a massive cluster of galaxies is assembling. Image via Joshua Borrow using C-EAGLE.

The new research was carried out using observations from the Multi Unit Spectroscopic Explorer (MUSE) at the European Southern Observatory’s Very Large Telescope. Their statement explained:

The astronomers detected the filaments of gas using the characteristic radiation produced when the neutral hydrogen gas they contain is excited by surrounding ultraviolet light and then returns to its lowest state of energy.

The detected radiation was too intense to originate only from the typical background level of ultraviolet light that permeates the universe, and the researchers’ models instead suggest that it is driven by the light emitted from the many star-forming galaxies and black holes in the region.

Lead author Hideki Umehata, of the RIKEN Cluster for Pioneering Research and the University of Tokyo, said:

The presence of such intense radiation suggests very strongly that gas falling along the filaments under the force of gravity triggers the formation of many starbursting galaxies and supermassive black holes, ultimately giving the universe the structure that we see today.

Previous observations have shown similar emission from blobs of gas extending beyond galaxies, but now we have been able to clearly show that these filaments stretch to much larger distances, going even beyond the edge of the field that we viewed.

This adds credence to the idea that these filaments are actually powering the intense activity that we see in galaxies within large structures assembling in the early universe.

Astronomers believe the early universe was nearly uniform as it expanded outward from the Big Bang. By a few billion years after the Big Bang, areas of slightly higher density had evolved to become galaxy clusters and groups, with sparsely populated regions devoid of galaxies in between. The universe as a whole evolved to this honeycomb-like structure, sometimes called the “cosmic web.” In this artist’s illustration, Mpc/h is a unit of distance, with 1 Mpc/h more than 3.2 million light-years. Image via Volker Springel, Virgo Consortium.

Bottom line: Astronomers in the U.K. and Japan probed the cosmic web, a large-scale structure composed of massive filaments of galaxies separated by giant voids. They found the filaments also contained significant amounts of gas, believed to help fuel the galaxies’ growth. The new observations give scientists a way to map the cosmic web directly and to understand in detail its role in regulating the formation of supermassive black holes and galaxies.

Source: Gas filaments of the cosmic web located around active galaxies in a protocluster

Via Durham University

from EarthSky https://ift.tt/2Mo5cfw

Today in science: 1st planet orbiting a sunlike star

Artist’s concept of 51 Pegasi b orbiting its parent star. Image via Dr. Seth Shostak/SPL.

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

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

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

It remains to be seen whether astronomers will accept the IAU’s name recommendation, or whether 51 Pegasi b, like so many objects in astronomy, will continue to have multiple names.

51 Pegasi b was the first, but now we know thousands of exoplanets. As of 2019, astronomers have discovered more than 4,000 exoplanets.

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

What do we know today of 51 Pegasi b, this world whose place in astronomical history is so secure? Its mass is about half that of Jupiter, and it’s thought to have a greater diameter than Jupiter (the biggest planet in our solar system), despite its smaller mass. 51 Pegasi b orbits very close to its parent star, requiring only 4 days to orbit its star, in contrast to 365 days for our Earth to orbit the sun and 12 years for Jupiter. In other words, 51 Pegasi b orbits very close to its star.

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

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

Consider that, before 51 Pegasi b, the search for exoplanets – worlds beyond our own solar system – was exceedingly difficult. Once astronomers began in earnest to search for them, they searched for decades before finding any. In nearly all cases, exoplanets cannot be seen in the light of their parent stars, and astronomers had to develop clever technologies in order to discover them. As with many extrasolar planets, 51 Pegasi b was found using the radial velocity method. Click here to learn more about how astronomers find exoplanets.

View larger. | The momentous discovery of the 1st exoplanet around a sunlike star – 51 Pegasi b – caused astronomers to question what they knew of our universe. It launched further searches for new worlds. Infographic via NASA/ JPL-Caltech.

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

from EarthSky https://ift.tt/338b03e

Artist’s concept of 51 Pegasi b orbiting its parent star. Image via Dr. Seth Shostak/SPL.

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

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

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

It remains to be seen whether astronomers will accept the IAU’s name recommendation, or whether 51 Pegasi b, like so many objects in astronomy, will continue to have multiple names.

51 Pegasi b was the first, but now we know thousands of exoplanets. As of 2019, astronomers have discovered more than 4,000 exoplanets.

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

What do we know today of 51 Pegasi b, this world whose place in astronomical history is so secure? Its mass is about half that of Jupiter, and it’s thought to have a greater diameter than Jupiter (the biggest planet in our solar system), despite its smaller mass. 51 Pegasi b orbits very close to its parent star, requiring only 4 days to orbit its star, in contrast to 365 days for our Earth to orbit the sun and 12 years for Jupiter. In other words, 51 Pegasi b orbits very close to its star.

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

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

Consider that, before 51 Pegasi b, the search for exoplanets – worlds beyond our own solar system – was exceedingly difficult. Once astronomers began in earnest to search for them, they searched for decades before finding any. In nearly all cases, exoplanets cannot be seen in the light of their parent stars, and astronomers had to develop clever technologies in order to discover them. As with many extrasolar planets, 51 Pegasi b was found using the radial velocity method. Click here to learn more about how astronomers find exoplanets.

View larger. | The momentous discovery of the 1st exoplanet around a sunlike star – 51 Pegasi b – caused astronomers to question what they knew of our universe. It launched further searches for new worlds. Infographic via NASA/ JPL-Caltech.

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

from EarthSky https://ift.tt/338b03e