Millions of stars

If you’re patient, you can click here to view in high resolution. | There may be 2.8 million stars in this image sequence, which is via ESA’s Gaia star-mapper.

The European Space Agency (ESA) released this image on September 4, 2017. It’s from its Gaia star-mapper – that awesome billion-star surveyor – whose job is detecting stars and measuring their properties in order to build up the most precise 3D map of the Milky Way, ever. Gaia uses a technique called astrometry; that is, it accurately measures the motions of individual stars. And who knew astrometry could be so cool? But it is. Over time, astronomers will be able to use Gaia’s data to peer back in time to understand the history, evolution and destiny of our Milky Way galaxy as a whole.

The image above – acquired on February 7, 2017 by Gaia – covers a region of our sky toward the center of the Milky Way galaxy, only two degrees below the galactic center. In other words, it’s looking toward what we earthlings know as the constellation Sagittarius the Archer, which is visible in the evening sky as seen from all of Earth every early September. In this specific Gaia field of view, along our line of sight from Earth, there’s a relatively low amount of interstellar dust, giving a window to stars close to the galactic center, ESA said. It added:

The stellar density here is an incredible 4.6 million stars per square degree. The image covers about 0.6 square degrees, making it conceivable that there are some 2.8 million stars captured in this image sequence alone.

In general, as Gaia registers stars, only data covering the object of interest are transmitted to the ground. However, in the densest regions on the sky there are more stars close to each other than the detection and processing system of Gaia can cope with, which could result in a less complete census in these crowded areas.

To help mitigate this, a scientific selection of high-density regions is made to cover them in a special imaging mode, as illustrated here. These types of observations are carried out routinely every time Gaia scans over these regions …

The image appears in strips, each representing a sky mapper CCD. The image has been lightly processed to bring out the contrast of the bright stars and darker traces of gas and dust. Zooming in reveals some imaging artifacts relating to the CCDs, including some vertical striping, as well as short bright streaks indicating cosmic rays. Analysis of these images will only start once the effort required by the routine data processing allows.

Gaia’s first catalog contains measurements for more than a billion stars, based on the first 14 months of data collection. It was released in September 2016. The next release is targeting April 2018, with subsequent releases foreseen for 2020 and 2022.

The animation below shows how Gaia’s camera works:

Bottom line: ESA just released this image sequence made by the Gaia star-mapper. It looks toward the center of our Milky Way galaxy and some approximately 2.8 million stars.

Via ESA

Read more from ESA about Gaia

from EarthSky http://ift.tt/2vZHBar

If you’re patient, you can click here to view in high resolution. | There may be 2.8 million stars in this image sequence, which is via ESA’s Gaia star-mapper.

The European Space Agency (ESA) released this image on September 4, 2017. It’s from its Gaia star-mapper – that awesome billion-star surveyor – whose job is detecting stars and measuring their properties in order to build up the most precise 3D map of the Milky Way, ever. Gaia uses a technique called astrometry; that is, it accurately measures the motions of individual stars. And who knew astrometry could be so cool? But it is. Over time, astronomers will be able to use Gaia’s data to peer back in time to understand the history, evolution and destiny of our Milky Way galaxy as a whole.

The image above – acquired on February 7, 2017 by Gaia – covers a region of our sky toward the center of the Milky Way galaxy, only two degrees below the galactic center. In other words, it’s looking toward what we earthlings know as the constellation Sagittarius the Archer, which is visible in the evening sky as seen from all of Earth every early September. In this specific Gaia field of view, along our line of sight from Earth, there’s a relatively low amount of interstellar dust, giving a window to stars close to the galactic center, ESA said. It added:

The stellar density here is an incredible 4.6 million stars per square degree. The image covers about 0.6 square degrees, making it conceivable that there are some 2.8 million stars captured in this image sequence alone.

In general, as Gaia registers stars, only data covering the object of interest are transmitted to the ground. However, in the densest regions on the sky there are more stars close to each other than the detection and processing system of Gaia can cope with, which could result in a less complete census in these crowded areas.

To help mitigate this, a scientific selection of high-density regions is made to cover them in a special imaging mode, as illustrated here. These types of observations are carried out routinely every time Gaia scans over these regions …

The image appears in strips, each representing a sky mapper CCD. The image has been lightly processed to bring out the contrast of the bright stars and darker traces of gas and dust. Zooming in reveals some imaging artifacts relating to the CCDs, including some vertical striping, as well as short bright streaks indicating cosmic rays. Analysis of these images will only start once the effort required by the routine data processing allows.

Gaia’s first catalog contains measurements for more than a billion stars, based on the first 14 months of data collection. It was released in September 2016. The next release is targeting April 2018, with subsequent releases foreseen for 2020 and 2022.

The animation below shows how Gaia’s camera works:

Bottom line: ESA just released this image sequence made by the Gaia star-mapper. It looks toward the center of our Milky Way galaxy and some approximately 2.8 million stars.

Via ESA

Read more from ESA about Gaia

from EarthSky http://ift.tt/2vZHBar

A new look at ocean worlds

This is Saturn’s moon Enceladus, as seen by the Cassini spacecraft. It’s thought to have a subsurface ocean and can be seen spewing water vapor from its interior. Photo via NASA/JPL-Caltech.

This article was originally published at AmericaSpace.com. Reprinted with permission.

NASA’s upcoming James Webb Space Telescope (JWST) will be used to study two of the most fascinating moons in our solar system – Europa and Enceladus, also known as ocean worlds since both have global oceans of water beneath their outer icy surfaces. The new observations will help scientists learn more about conditions on these worlds and guide the development of future robotic missions.

Both moons are exciting targets since Europa’s surface has deposits of minerals thought to have come up from the ocean below, and Enceladus has huge plumes of water vapor erupting through fissures in the icy surface, originating from the subsurface ocean. Europa may also have plumes, which have been tentatively identified but not confirmed yet. Enceladus’ plumes also contain organic compounds of various complexities, which were sampled directly by the Cassini spacecraft multiple times.

Astronomer Heidi Hammel is executive vice president of the Association of Universities for Research in Astronomy (AURA). She is spearheading the effort to study our solar system with the Webb telescope. She said:

We chose these two moons because of their potential to exhibit chemical signatures of astrobiological interest.

Composite image showing the possible water vapor plumes near the south pole of Jupiter’s moon Europa, at about the 7 o’clock position. The image of Europa, from the Galileo and Voyager missions, is superimposed on the Hubble data. Image via NASA/ESA/W. Sparks (STScI)/USGS Astrogeology Science Center.

Astronomers will use Webb’s near-infrared camera (NIRCam) to take high-resolution images of Europa’s surface, to search for hot regions related to plumes and active geological processes. If a plume is found, they can then use Webb’s near-infrared spectrograph (NIRSpec) and mid-infrared instrument (MIRI) to analyze the plume’s composition. This video below shows possible results of using spectroscopy on Europa’s water plumes, obtainable using the Webb telescope’s NIRSpec instrument.

Geronimo Villanueva, a planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, is the lead scientist on the Webb telescope’s observation of Europa and Enceladus. He said:

Are they made of water ice? Is hot water vapor being released? What is the temperature of the active regions and the emitted water? Webb telescope’s measurements will allow us to address these questions with unprecedented accuracy and precision.

JWST will be able to study Enceladus’ plumes and surface in a similar manner, even though it is about 10 times smaller than Europa as seen by the telescope.

For both moons, a focus will be to search for organic signatures such as methane, methanol, and ethane in the plumes. Evidence of life itself, like microbes, would be more difficult since some life-like processes could also have a geological explanation. Villanueva noted:

We only expect detections if the plumes are particularly active and if they are organic-rich.

JWST is the successor to the Hubble Space Telescope (HST) and will be the most powerful space-based telescope ever built. It is an international project led by NASA, along with the European Space Agency (ESA) and the Canadian Space Agency (CSA).

Even if JWST isn’t able to find signs of life on either moon, it will be another huge step in understanding what conditions are like, both on their surfaces and below the ice in the oceans themselves, building on results from spacecraft such as Galileo and Cassini. It will help prepare the way for future, more advanced probes on the drawing boards now which may be able to answer that question of whether life has ever existed on (in) these far-off ocean worlds.

Diagram of an interior cross-section of the crust of Enceladus, showing how hydrothermal activity is thought to be causing the plumes of water vapor on the surface. Image via NASA-GSFC/SVS/NASA/JPL-Caltech/Southwest Research Institute.

Bottom line: The James Webb Space Telescope will be used in part to study our own solar system, for example, Jupiter’s moon Europa and Saturn’s moon Enceladus, both considered ocean worlds.

from EarthSky http://ift.tt/2x4WPjy

This is Saturn’s moon Enceladus, as seen by the Cassini spacecraft. It’s thought to have a subsurface ocean and can be seen spewing water vapor from its interior. Photo via NASA/JPL-Caltech.

This article was originally published at AmericaSpace.com. Reprinted with permission.

NASA’s upcoming James Webb Space Telescope (JWST) will be used to study two of the most fascinating moons in our solar system – Europa and Enceladus, also known as ocean worlds since both have global oceans of water beneath their outer icy surfaces. The new observations will help scientists learn more about conditions on these worlds and guide the development of future robotic missions.

Both moons are exciting targets since Europa’s surface has deposits of minerals thought to have come up from the ocean below, and Enceladus has huge plumes of water vapor erupting through fissures in the icy surface, originating from the subsurface ocean. Europa may also have plumes, which have been tentatively identified but not confirmed yet. Enceladus’ plumes also contain organic compounds of various complexities, which were sampled directly by the Cassini spacecraft multiple times.

Astronomer Heidi Hammel is executive vice president of the Association of Universities for Research in Astronomy (AURA). She is spearheading the effort to study our solar system with the Webb telescope. She said:

We chose these two moons because of their potential to exhibit chemical signatures of astrobiological interest.

Composite image showing the possible water vapor plumes near the south pole of Jupiter’s moon Europa, at about the 7 o’clock position. The image of Europa, from the Galileo and Voyager missions, is superimposed on the Hubble data. Image via NASA/ESA/W. Sparks (STScI)/USGS Astrogeology Science Center.

Astronomers will use Webb’s near-infrared camera (NIRCam) to take high-resolution images of Europa’s surface, to search for hot regions related to plumes and active geological processes. If a plume is found, they can then use Webb’s near-infrared spectrograph (NIRSpec) and mid-infrared instrument (MIRI) to analyze the plume’s composition. This video below shows possible results of using spectroscopy on Europa’s water plumes, obtainable using the Webb telescope’s NIRSpec instrument.

Geronimo Villanueva, a planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, is the lead scientist on the Webb telescope’s observation of Europa and Enceladus. He said:

Are they made of water ice? Is hot water vapor being released? What is the temperature of the active regions and the emitted water? Webb telescope’s measurements will allow us to address these questions with unprecedented accuracy and precision.

JWST will be able to study Enceladus’ plumes and surface in a similar manner, even though it is about 10 times smaller than Europa as seen by the telescope.

For both moons, a focus will be to search for organic signatures such as methane, methanol, and ethane in the plumes. Evidence of life itself, like microbes, would be more difficult since some life-like processes could also have a geological explanation. Villanueva noted:

We only expect detections if the plumes are particularly active and if they are organic-rich.

JWST is the successor to the Hubble Space Telescope (HST) and will be the most powerful space-based telescope ever built. It is an international project led by NASA, along with the European Space Agency (ESA) and the Canadian Space Agency (CSA).

Even if JWST isn’t able to find signs of life on either moon, it will be another huge step in understanding what conditions are like, both on their surfaces and below the ice in the oceans themselves, building on results from spacecraft such as Galileo and Cassini. It will help prepare the way for future, more advanced probes on the drawing boards now which may be able to answer that question of whether life has ever existed on (in) these far-off ocean worlds.

Diagram of an interior cross-section of the crust of Enceladus, showing how hydrothermal activity is thought to be causing the plumes of water vapor on the surface. Image via NASA-GSFC/SVS/NASA/JPL-Caltech/Southwest Research Institute.

Bottom line: The James Webb Space Telescope will be used in part to study our own solar system, for example, Jupiter’s moon Europa and Saturn’s moon Enceladus, both considered ocean worlds.

from EarthSky http://ift.tt/2x4WPjy

Earth passing between Neptune and sun

On September 4, Earth and Neptune are closest for 2017. One day later, on September 5, Neptune reaches opposition, when it is 180 degrees from the sun in our sky. By closest, we don’t mean close. Neptune, the 8th planet outward from the sun, lodges in the outskirts of our solar system and at opposition lies 29 times farther away from Earth than Earth lies from our sun.

Neptune is said to be at opposition – opposite the sun in Earth’s sky – whenever our planet Earth in its orbit passes between the sun and Neptune. That’s what’s happening over the next couple of days. In 2017, the moon turns full only one day after Neptune reaches opposition.

In fact, the full moon will actually occult (swing in front of) Neptune on the night of September 5-6, 2017 (though only in the extreme southern part of the globe). This occultation of Neptune will be nearly impossible to observe, so the International Occultation Timing Association (IOTA) doesn’t bother to list the occultation times as it does for other lunar occultations of Neptune.

Because we’re more or less between Netune and the sun around now, Neptune is rising in the east around the time of sunset, climbing highest up for the night around midnight and setting in the west around sunrise.

As viewed from Earth now, this world is in front of the constellation Aquarius the Water Carrier.

In 1989, NASA’s Voyager 2 became the first spacecraft to observe Neptune. More about this image and more photos from Voyager 1’s flyby.

Opposition is a special event. When any planet outside of Earth’s orbit is at or near opposition, Earth comes closest to that planet for the year, and that planet, in turn, shines most brightly in our sky. Even at opposition, however, Neptune, the eighth planet outward from the sun, is not all that close and it’s not all that bright.

In fact, Neptune is the only major solar system planet that’s absolutely not visible to the unaided eye. This world is about five times fainter than the dimmest star that you can see on an inky black night. You’ll need binoculars (at least) and a detailed sky chart to see Neptune in front of the constellation Aquarius.

Even at that, it’ll only look like a faint star. Many sky watchers will find the faint star Lambda Aquarii with the unaided eye and then star-hop to Neptune.

Neptune, the fourth-largest planet, is just a touch smaller than Uranus, the third-largest. You’d have to line up four Earths side by side to equal the diameter of either planet.

Okay, so it’s unlikely you’ll see Neptune unless you have optical aid and a detailed star chart. But there are four bright planets in the September 2017 sky. Look for Jupiter low in the west after sunset and for Venus, Mercury and Mars in the east before sunrise. Saturn is found in the southern sky at nightfall (or as seen from the Southern Hemisphere: high overhead).

Read more: September guide to the bright planets

Bottom line: We’re closest to Neptune for 2017 on September 4. Neptune’s opposition – when it’s 180 degrees from the sun on the sky’s dome – is one day later, on September 5. You need optical aid to spot it. Links to charts here.

Get charts for observing Uranus and Neptune for the 2017-2018 observing season

from EarthSky http://ift.tt/2cesTUU

On September 4, Earth and Neptune are closest for 2017. One day later, on September 5, Neptune reaches opposition, when it is 180 degrees from the sun in our sky. By closest, we don’t mean close. Neptune, the 8th planet outward from the sun, lodges in the outskirts of our solar system and at opposition lies 29 times farther away from Earth than Earth lies from our sun.

Neptune is said to be at opposition – opposite the sun in Earth’s sky – whenever our planet Earth in its orbit passes between the sun and Neptune. That’s what’s happening over the next couple of days. In 2017, the moon turns full only one day after Neptune reaches opposition.

In fact, the full moon will actually occult (swing in front of) Neptune on the night of September 5-6, 2017 (though only in the extreme southern part of the globe). This occultation of Neptune will be nearly impossible to observe, so the International Occultation Timing Association (IOTA) doesn’t bother to list the occultation times as it does for other lunar occultations of Neptune.

Because we’re more or less between Netune and the sun around now, Neptune is rising in the east around the time of sunset, climbing highest up for the night around midnight and setting in the west around sunrise.

As viewed from Earth now, this world is in front of the constellation Aquarius the Water Carrier.

In 1989, NASA’s Voyager 2 became the first spacecraft to observe Neptune. More about this image and more photos from Voyager 1’s flyby.

Opposition is a special event. When any planet outside of Earth’s orbit is at or near opposition, Earth comes closest to that planet for the year, and that planet, in turn, shines most brightly in our sky. Even at opposition, however, Neptune, the eighth planet outward from the sun, is not all that close and it’s not all that bright.

In fact, Neptune is the only major solar system planet that’s absolutely not visible to the unaided eye. This world is about five times fainter than the dimmest star that you can see on an inky black night. You’ll need binoculars (at least) and a detailed sky chart to see Neptune in front of the constellation Aquarius.

Even at that, it’ll only look like a faint star. Many sky watchers will find the faint star Lambda Aquarii with the unaided eye and then star-hop to Neptune.

Neptune, the fourth-largest planet, is just a touch smaller than Uranus, the third-largest. You’d have to line up four Earths side by side to equal the diameter of either planet.

Okay, so it’s unlikely you’ll see Neptune unless you have optical aid and a detailed star chart. But there are four bright planets in the September 2017 sky. Look for Jupiter low in the west after sunset and for Venus, Mercury and Mars in the east before sunrise. Saturn is found in the southern sky at nightfall (or as seen from the Southern Hemisphere: high overhead).

Read more: September guide to the bright planets

Bottom line: We’re closest to Neptune for 2017 on September 4. Neptune’s opposition – when it’s 180 degrees from the sun on the sky’s dome – is one day later, on September 5. You need optical aid to spot it. Links to charts here.

Get charts for observing Uranus and Neptune for the 2017-2018 observing season

from EarthSky http://ift.tt/2cesTUU

2017 SkS Weekly Climate Change & Global Warming Digest #35

Story of the Week... Editorial of the Week...Toon of the Week... Coming Soon on SkS... Poster of the Week... Climate Feedback Reviews... SkS Week in Review... 97 Hours of Consensus...

Story of the Week...

The Strange Future Hurricane Harvey Portends

 A Syrian refugee walks toward his tent at Zaatari refugee camp through puddles and in front of storm clouds. 

Humans have begun an international project to move water around the world, far more ambitious than any network of aqueducts or hydroelectric dams ever constructed or conceived. The drivers of this global system are billowing vapors, which trap heat and propel the world’s water faster and farther around the globe. The first results of this project may already be seen in the outrageous rainfall totals of storms like Hurricane Harvey, or in landslides on remote mountain hillsides, and even in the changing saltiness of the oceans.

The Earth system is getting warmer. Water is evaporating faster. There’s more of it in the air. It’s moving through the system faster. As a result, the coming centuries will play out under a new atmospheric regime, one with more extreme rain, falling in patterns unfamiliar to those around which civilization has grown.

“Basically the idea is that as the climate warms there’s more energy in the atmosphere,” says Gabriel Bowen, a geochemist at the University of Utah. “That drives a more vigorous water cycle: Evaporation rates go up, precipitation rates go up—there’s just more water moving through that cycle faster and more intensely.”

For each degree Celsius of warming the atmosphere is able to hold 6 percent more water. For a planet that’s expected to warm by 4 degrees by the end of the century, that means a transition to a profoundly different climate.

“Rainfall extremes have increased in intensity I think at every latitude in the northern hemisphere,” says Massachusetts Institute of Technology climate scientist Paul O’Gorman.

The Strange Future Hurricane Harvey Portends by Peter Brannen, The Atlantic, Aug 31, 2017 

---

Editorial of the Week...

Harvey should be a warning to Trump that climate change is a global threat

As rains fell and floodwaters rose in Houston, President Trump took to Twitter with an “oh, gosh” tweet: “Wow - Now experts are calling #Harvey a once in 500 year flood! We have an all out effort going, and going well!”

How refreshing it is when the president directs our attention to the words of experts — people who ascertain facts, study the issues, dissect the causes of problems, and put their biases and suppositions aside to figure out solutions.

If Trump himself were to consult the experts — such as, you know, climate scientists — he would learn that global warming is real. He’d also learn that although warming did not cause Hurricane Harvey, it certainly makes such storms stronger, more unpredictable and quicker to intensify. Experts — there’s that word again — say that warmer air temperatures mean more evaporation of moisture from the seas to the skies, and thus more rainfall from storms. Warmer seas — including the Gulf of Mexico — intensify storms, from their size to their wind speeds, and amplify storm surges. (In southeast Texas, the flat geography allows a surging Gulf to intrude farther inland.) Another wrinkle, according to atmospheric scientist Michael E. Mann: Climate change modeling suggests that human-propelled global warming could lead to weaker prevailing winds and a jet stream tracking father north. And that appears to have been what led Harvey to park over southeast Texas and dump more than 40 inches of water in places rather than spreading the rain (and pain) around or drifting back out over the Gulf.

Harvey should be a warning to Trump that climate change is a global threat, Opinion by Editorial Board, Los Angeles Times, Aug 30, 2017 

---

Toon of the Week...

 

---

Coming Soon on SkS...

• I was an Exxon-funded climate scientist (Katharine Hayhoe)
• Denying Hurricane Harvey’s climate links will only increase future suffering (Dana)
• Research this week (Ari)
• Guest post (John Abraham)
• Why the 97% climate consensus is important (Dana, John Cook, Sander van der Linden, Ed Maibach & Tony Lieserowitz)
• 2017 SkS Weekly Climate Change & Global Warming News Roundup #36 (John Hartz)
• 2017 SkS Weekly Climate Change & Global Waming Digest #36 (John Hartz)

---

Poster of the Week...

 

---

Climate Feedback Reviews...

Climate Feedback asked its network of scientists to review the article, Did Climate Change Intensify Hurricane Harvey? by Robinson Meyer, The Atlantic, Aug 27, 2017

Three scientists analyzed the article and estimated its overall scientific credibility to be ‘high’ to ‘very high’. 

A majority of reviewers tagged the article as: Insightful.

Review Summary

This article in The Atlantic attempted to investigate what can be said about the relationship between Tropical Storm Harvey and climate change. Harvey’s record rainfall totals around Houston, Texas are partly the result of how long it has persisted in the same location, making it an unusual storm.

Scientists who reviewed the article indicated that it provides an accurate summary of how tropical cyclones are expected to change due to global warming, as well as what aspects of Harvey do not have clearly understood relationships with climate change. 

The Atlantic accurately explores climate context for Tropical Storm Harvey, Climate 
Feedback, Aug 29, 2017 

---

SkS Week in Review... 

• 2017 SkS Weekly Climate Change & Global Warming News Roundup #35 by John Hartz
• The Trump administration wants to bail out failed contrarian climate scientists by John Abraham (Climate Consensus - the 97%)
• New research, August 21-27, 2017 by Ari Jokimäki
• Exit, Pursued by a Crab by Andy Skuce
• Study: Katharine Hayhoe is successfully convincing doubtful evangelicals about climate change by Dana Nuccitelli (Climate Consensus - the 97%)
• 2017 SkS Weekly Climate Change & Global Warming Digest #34 by John Hartz 

---

97 Hours of Consensus...

 

 

Nathan Bindoff's bio page

Quote provided by email 

High resolution JPEG (1024 pixels wide)

from Skeptical Science http://ift.tt/2guVMyD

Story of the Week... Editorial of the Week...Toon of the Week... Coming Soon on SkS... Poster of the Week... Climate Feedback Reviews... SkS Week in Review... 97 Hours of Consensus...

Story of the Week...

The Strange Future Hurricane Harvey Portends

 A Syrian refugee walks toward his tent at Zaatari refugee camp through puddles and in front of storm clouds. 

Humans have begun an international project to move water around the world, far more ambitious than any network of aqueducts or hydroelectric dams ever constructed or conceived. The drivers of this global system are billowing vapors, which trap heat and propel the world’s water faster and farther around the globe. The first results of this project may already be seen in the outrageous rainfall totals of storms like Hurricane Harvey, or in landslides on remote mountain hillsides, and even in the changing saltiness of the oceans.

The Earth system is getting warmer. Water is evaporating faster. There’s more of it in the air. It’s moving through the system faster. As a result, the coming centuries will play out under a new atmospheric regime, one with more extreme rain, falling in patterns unfamiliar to those around which civilization has grown.

“Basically the idea is that as the climate warms there’s more energy in the atmosphere,” says Gabriel Bowen, a geochemist at the University of Utah. “That drives a more vigorous water cycle: Evaporation rates go up, precipitation rates go up—there’s just more water moving through that cycle faster and more intensely.”

For each degree Celsius of warming the atmosphere is able to hold 6 percent more water. For a planet that’s expected to warm by 4 degrees by the end of the century, that means a transition to a profoundly different climate.

“Rainfall extremes have increased in intensity I think at every latitude in the northern hemisphere,” says Massachusetts Institute of Technology climate scientist Paul O’Gorman.

The Strange Future Hurricane Harvey Portends by Peter Brannen, The Atlantic, Aug 31, 2017 

---

Editorial of the Week...

Harvey should be a warning to Trump that climate change is a global threat

As rains fell and floodwaters rose in Houston, President Trump took to Twitter with an “oh, gosh” tweet: “Wow - Now experts are calling #Harvey a once in 500 year flood! We have an all out effort going, and going well!”

How refreshing it is when the president directs our attention to the words of experts — people who ascertain facts, study the issues, dissect the causes of problems, and put their biases and suppositions aside to figure out solutions.

If Trump himself were to consult the experts — such as, you know, climate scientists — he would learn that global warming is real. He’d also learn that although warming did not cause Hurricane Harvey, it certainly makes such storms stronger, more unpredictable and quicker to intensify. Experts — there’s that word again — say that warmer air temperatures mean more evaporation of moisture from the seas to the skies, and thus more rainfall from storms. Warmer seas — including the Gulf of Mexico — intensify storms, from their size to their wind speeds, and amplify storm surges. (In southeast Texas, the flat geography allows a surging Gulf to intrude farther inland.) Another wrinkle, according to atmospheric scientist Michael E. Mann: Climate change modeling suggests that human-propelled global warming could lead to weaker prevailing winds and a jet stream tracking father north. And that appears to have been what led Harvey to park over southeast Texas and dump more than 40 inches of water in places rather than spreading the rain (and pain) around or drifting back out over the Gulf.

Harvey should be a warning to Trump that climate change is a global threat, Opinion by Editorial Board, Los Angeles Times, Aug 30, 2017 

---

Toon of the Week...

 

---

Coming Soon on SkS...

• I was an Exxon-funded climate scientist (Katharine Hayhoe)
• Denying Hurricane Harvey’s climate links will only increase future suffering (Dana)
• Research this week (Ari)
• Guest post (John Abraham)
• Why the 97% climate consensus is important (Dana, John Cook, Sander van der Linden, Ed Maibach & Tony Lieserowitz)
• 2017 SkS Weekly Climate Change & Global Warming News Roundup #36 (John Hartz)
• 2017 SkS Weekly Climate Change & Global Waming Digest #36 (John Hartz)

---

Poster of the Week...

 

---

Climate Feedback Reviews...

Climate Feedback asked its network of scientists to review the article, Did Climate Change Intensify Hurricane Harvey? by Robinson Meyer, The Atlantic, Aug 27, 2017

Three scientists analyzed the article and estimated its overall scientific credibility to be ‘high’ to ‘very high’. 

A majority of reviewers tagged the article as: Insightful.

Review Summary

This article in The Atlantic attempted to investigate what can be said about the relationship between Tropical Storm Harvey and climate change. Harvey’s record rainfall totals around Houston, Texas are partly the result of how long it has persisted in the same location, making it an unusual storm.

Scientists who reviewed the article indicated that it provides an accurate summary of how tropical cyclones are expected to change due to global warming, as well as what aspects of Harvey do not have clearly understood relationships with climate change. 

The Atlantic accurately explores climate context for Tropical Storm Harvey, Climate 
Feedback, Aug 29, 2017 

---

SkS Week in Review... 

• 2017 SkS Weekly Climate Change & Global Warming News Roundup #35 by John Hartz
• The Trump administration wants to bail out failed contrarian climate scientists by John Abraham (Climate Consensus - the 97%)
• New research, August 21-27, 2017 by Ari Jokimäki
• Exit, Pursued by a Crab by Andy Skuce
• Study: Katharine Hayhoe is successfully convincing doubtful evangelicals about climate change by Dana Nuccitelli (Climate Consensus - the 97%)
• 2017 SkS Weekly Climate Change & Global Warming Digest #34 by John Hartz 

---

97 Hours of Consensus...

 

 

Nathan Bindoff's bio page

Quote provided by email 

High resolution JPEG (1024 pixels wide)

from Skeptical Science http://ift.tt/2guVMyD

How Earth looks from outer space

View larger. | Earth seen behind the rings of Saturn. See us in the lower right? Mars and Venus are in the upper left. Image via the Cassini spacecraft, July 19, 2013.

How far away from Earth can we be, to see it still with our own eyes?

To answer this question, you have to take into account how brightly Earth reflects sunlight. And the sun itself is an important factor. As seen from any great distance, Earth appears right next to the sun; from a great distance, the glare of our local star would make Earth difficult or impossible to see. But spacecraft exploring our solar system have given us marvelous views of Earth. So imagine blasting off and being about 300 kilometers – about 200 miles – above Earth’s surface. That’s the height at which the International Space Station (ISS) orbits. The surface of the Earth looms large in the window of ISS. In the daytime, you can clearly see major landforms. At night, you see the lights of Earth’s cities.

Earth in daylight, from ISS in 2012. The U.S. Great Lakes shine in the sun. Read more about this image.

Earth at night, from ISS in 2012. Ireland in the foreground, and the United Kingdom in the back and to the right. A bright sunrise is in the background. Greens and purples shows an aurora borealis along the rest of the horizon.

As you pass the moon – about 380,000 kilometers away – or a quarter million miles – Earth looks like a bright ball in space – not very different from the way the moon looks to us. The first images of the Earth from the moon came from the Apollo mission. Apollo 8 in 1968 was the first human spaceflight to leave Earth orbit. It was the first earthly spacecraft to be captured by and escape from the gravitational field of another celestial body, in this case the moon. It was the first voyage in which humans visited another world and returned to return to Earth.

Earth seen from moon via Apollo 8 astronauts in 1968. Image via NASA

Then came the mind-blowing moment of seeing both the Earth and moon together in space. The next picture shows a crescent-shaped Earth and moon – the first of its kind ever taken by a spacecraft – on September 18, 1977. NASA’s Voyager 1 spacecraft was 7.25 million miles (11.66 million kilometers) from Earth at the time.

The moon (top) and Earth as viewed by Voyager in 1977. Image via NASA

Now moon exploration has become more common, though still amazing. This mosaic below shows images of Earth and the moon acquired by the multispectral imager on the Near Earth Asteroid Rendezvous Spacecraft (NEAR) on January 23, 1998, 19 hours after the spacecraft swung by Earth on its way to the asteroid 433 Eros. The images of both were taken from a range of 250,000 miles (400,000 kilometers), approximately the same as the distance between the two bodies.

Earth and moon seen by NEAR spacecraft in 1998. Read more about this image.

The robotic Kaguya spacecraft orbited around Earth’s moon in 2007. Launched by Jpan, and officially named the Selenological and Engineering Explorer (SELENE), studied the origin and evolution of the moon. The frame below is from Kaguya’s onboard HDTV camera.

Earth viewed from the moon by Kaguya in 2007. Image via SELENE Team, JAXA, NHK

Another image from Kaguya, which got footage and stills of Earth setting. Remember that, if you were on the moon, you would not see Earth rise or set. But spacecraft in orbit around the moon do experience this scene.

Speeding outward from the Earth and moon system, you pass the orbits of the planets Mars, Jupiter, Saturn, Uranus and Neptune. From all of these worlds, Earth looks like a star – which gets fainter as you get farther away. From the world next door, though, Mars, a human observer with normal vision could easily see Earth and the moon as two distinct, bright evening or morning “stars.”

Earth and moon, as seen from Mars by the Curiosity rover on January 31, 2014. Read more about this image.

This is the famous image known as Pale Blue Dot. It’s a photograph of Earth taken on February 14, 1990, by the Voyager 1 space probe from a record distance of about 6 billion kilometers (3.7 billion miles). Earth is the blueish-white speck approximately halfway down the brown band to the right.

The light from Earth finally becomes too faint to see with the eye alone at around 14 billion kilometers – about 9 billion miles – from home – around the outer limit of our solar system – nowhere near as far as even the next-nearest star. Of course, if an astronaut or alien had a telescope, he or she could definitely see Earth further away than that.

Bottom line: How far away in space can you view Earth with the eye alone? About as far away as the outer reaches of our own solar system at about 14 billion kilometers – about 9 billion miles – from home.

Ten more things you may not know about the solar system

What’s the youngest moon you can see?

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View larger. | Earth seen behind the rings of Saturn. See us in the lower right? Mars and Venus are in the upper left. Image via the Cassini spacecraft, July 19, 2013.

How far away from Earth can we be, to see it still with our own eyes?

To answer this question, you have to take into account how brightly Earth reflects sunlight. And the sun itself is an important factor. As seen from any great distance, Earth appears right next to the sun; from a great distance, the glare of our local star would make Earth difficult or impossible to see. But spacecraft exploring our solar system have given us marvelous views of Earth. So imagine blasting off and being about 300 kilometers – about 200 miles – above Earth’s surface. That’s the height at which the International Space Station (ISS) orbits. The surface of the Earth looms large in the window of ISS. In the daytime, you can clearly see major landforms. At night, you see the lights of Earth’s cities.

Earth in daylight, from ISS in 2012. The U.S. Great Lakes shine in the sun. Read more about this image.

Earth at night, from ISS in 2012. Ireland in the foreground, and the United Kingdom in the back and to the right. A bright sunrise is in the background. Greens and purples shows an aurora borealis along the rest of the horizon.

As you pass the moon – about 380,000 kilometers away – or a quarter million miles – Earth looks like a bright ball in space – not very different from the way the moon looks to us. The first images of the Earth from the moon came from the Apollo mission. Apollo 8 in 1968 was the first human spaceflight to leave Earth orbit. It was the first earthly spacecraft to be captured by and escape from the gravitational field of another celestial body, in this case the moon. It was the first voyage in which humans visited another world and returned to return to Earth.

Earth seen from moon via Apollo 8 astronauts in 1968. Image via NASA

Then came the mind-blowing moment of seeing both the Earth and moon together in space. The next picture shows a crescent-shaped Earth and moon – the first of its kind ever taken by a spacecraft – on September 18, 1977. NASA’s Voyager 1 spacecraft was 7.25 million miles (11.66 million kilometers) from Earth at the time.

The moon (top) and Earth as viewed by Voyager in 1977. Image via NASA

Now moon exploration has become more common, though still amazing. This mosaic below shows images of Earth and the moon acquired by the multispectral imager on the Near Earth Asteroid Rendezvous Spacecraft (NEAR) on January 23, 1998, 19 hours after the spacecraft swung by Earth on its way to the asteroid 433 Eros. The images of both were taken from a range of 250,000 miles (400,000 kilometers), approximately the same as the distance between the two bodies.

Earth and moon seen by NEAR spacecraft in 1998. Read more about this image.

The robotic Kaguya spacecraft orbited around Earth’s moon in 2007. Launched by Jpan, and officially named the Selenological and Engineering Explorer (SELENE), studied the origin and evolution of the moon. The frame below is from Kaguya’s onboard HDTV camera.

Earth viewed from the moon by Kaguya in 2007. Image via SELENE Team, JAXA, NHK

Another image from Kaguya, which got footage and stills of Earth setting. Remember that, if you were on the moon, you would not see Earth rise or set. But spacecraft in orbit around the moon do experience this scene.

Speeding outward from the Earth and moon system, you pass the orbits of the planets Mars, Jupiter, Saturn, Uranus and Neptune. From all of these worlds, Earth looks like a star – which gets fainter as you get farther away. From the world next door, though, Mars, a human observer with normal vision could easily see Earth and the moon as two distinct, bright evening or morning “stars.”

Earth and moon, as seen from Mars by the Curiosity rover on January 31, 2014. Read more about this image.

This is the famous image known as Pale Blue Dot. It’s a photograph of Earth taken on February 14, 1990, by the Voyager 1 space probe from a record distance of about 6 billion kilometers (3.7 billion miles). Earth is the blueish-white speck approximately halfway down the brown band to the right.

The light from Earth finally becomes too faint to see with the eye alone at around 14 billion kilometers – about 9 billion miles – from home – around the outer limit of our solar system – nowhere near as far as even the next-nearest star. Of course, if an astronaut or alien had a telescope, he or she could definitely see Earth further away than that.

Bottom line: How far away in space can you view Earth with the eye alone? About as far away as the outer reaches of our own solar system at about 14 billion kilometers – about 9 billion miles – from home.

Ten more things you may not know about the solar system

What’s the youngest moon you can see?

from EarthSky http://ift.tt/1hyTRI2

Autumn is coming!

Image via Manish Mamtani Photography.

from EarthSky http://ift.tt/2iSUstS

Image via Manish Mamtani Photography.

from EarthSky http://ift.tt/2iSUstS

Orion’s Belt points to dazzling Sirius

It’s one of the neatest tricks in all the heavens … Orion’s Belt points to Sirius in the constellation Canis Major the Greater Dog. Sirius is the brightest star in the nighttime sky. It’s up before dawn now but will be shifting into the evening sky as the months pass. Orion is found in the predawn morning sky every September.

Sirius is Dog Star and brightest star

Yes, you can find Orion. If you go outside and look south to southeast before dawn now, you’ll notice Orion’s Belt, which consists of a short, straight row of medium-bright stars. Just draw a line through Orion’s Belt and extend that line toward the horizon. You’ll easily spot Sirius, the sky’s brightest star.

Sirius is in the constellation Canis Major the Greater Dog. It’s often called the Dog Star.

There are no planets brighter than the star Sirius in the September 2016 morning sky. Although the planets Jupiter and Venus are brighter than Sirius, Jupiter is now lost in the glare of the setting sun, and Venus shines for only a brief while after sunset. Once again, use Orion’s Belt to locate Sirius in the southeast sky.

Orion, Sirius, Venus and more as seen on August 30, 2017 by Tom Wildoner. He took the photo from the U.S. state of Pennsylvannia, but these stars and Venus can be seen from around the world now, in the direction of sunrise, before the sun comes up. Read more about this photo.

Bottom line: In September 2017, you’ll find the constellation Orion, who three Belt stars make a short, straight row in the southeast before dawn. Orion’s Belt points to Sirius, the brightest star of the nighttime sky.

Fastest sunsets of the year around equinox time

Help support EarthSky! Check out the EarthSky store for fun astronomy gifts and tools for all ages!

EarthSky astronomy kits are perfect for beginners. Order yours from the EarthSky store.

from EarthSky http://ift.tt/OBJOwP

It’s one of the neatest tricks in all the heavens … Orion’s Belt points to Sirius in the constellation Canis Major the Greater Dog. Sirius is the brightest star in the nighttime sky. It’s up before dawn now but will be shifting into the evening sky as the months pass. Orion is found in the predawn morning sky every September.

Sirius is Dog Star and brightest star

Yes, you can find Orion. If you go outside and look south to southeast before dawn now, you’ll notice Orion’s Belt, which consists of a short, straight row of medium-bright stars. Just draw a line through Orion’s Belt and extend that line toward the horizon. You’ll easily spot Sirius, the sky’s brightest star.

Sirius is in the constellation Canis Major the Greater Dog. It’s often called the Dog Star.

There are no planets brighter than the star Sirius in the September 2016 morning sky. Although the planets Jupiter and Venus are brighter than Sirius, Jupiter is now lost in the glare of the setting sun, and Venus shines for only a brief while after sunset. Once again, use Orion’s Belt to locate Sirius in the southeast sky.

Orion, Sirius, Venus and more as seen on August 30, 2017 by Tom Wildoner. He took the photo from the U.S. state of Pennsylvannia, but these stars and Venus can be seen from around the world now, in the direction of sunrise, before the sun comes up. Read more about this photo.

Bottom line: In September 2017, you’ll find the constellation Orion, who three Belt stars make a short, straight row in the southeast before dawn. Orion’s Belt points to Sirius, the brightest star of the nighttime sky.

Fastest sunsets of the year around equinox time

Help support EarthSky! Check out the EarthSky store for fun astronomy gifts and tools for all ages!

EarthSky astronomy kits are perfect for beginners. Order yours from the EarthSky store.

from EarthSky http://ift.tt/OBJOwP