July guide to the bright planets

Look for the moon near the planet Jupiter and the star Spica on June 30, July 1 and 2. Read more.

Three of the five bright planets are easy to see in July, 2017: Jupiter, Saturn and Venus. Bright Jupiter is the first “star” to pop into view at nightfall and stays out until late night. Golden Saturn is up in the east at nightfall and stays out for most of the night. Elusive Mercury is not as easy to catch after sunset, because it appears low in the west at dusk. Brilliant Venus rises before the sun, shining in front of the constellation Taurus the Bull. Red Mars, buried deep in the glare of evening twilight, cannot be seen from Earth this month. Follow the links below to learn more about the planets in July 2017.

Jupiter brightest “star” in evening sky

Saturn out nearly all night

Venus, brilliant in east at morning dawn

Mars lost in the sun’s glare

Mercury briefly visible after sunset

Like what EarthSky offers? Sign up for our free daily newsletter today!

Astronomy events, star parties, festivals, workshops

Visit a new EarthSky feature – Best Places to Stargaze – and add your fav.

Look for the moon in the vicinity of Jupiter and the nearby star Spica for several days, centered on June 28. Read more.

Jupiter brightest “star” in evening sky. Jupiter reached opposition on April 7. That is, it was opposite the sun as seen from Earth then and so was appearing in our sky all night. The giant planet came closest to Earth for 2017 one day later, on April 8. So Jupiter shone at its brightest and best in April, never fear. It’ll still be blazing away in July! Jupiter beams as the third-brightest celestial body in the nighttime sky, after the moon and Venus. In July, Jupiter shines from dusk until late evening or around midnight; meanwhile, Venus appears only before dawn.

Click here for an almanac telling you Jupiter’s setting time and Venus’ rising time in your sky.

Watch for the moon to join up with Jupiter for several days, centered on or near July 28. See the above sky chart. Wonderful sight!

From the Northern Hemisphere, Jupiter appears in the southwestern sky first thing at dusk; and from the Southern Hemisphere, Jupiter appears high overhead at dusk or nightfall. From all of Earth, Jupiter sinks in a westerly direction throughout the night, as Earth spins under the sky. In early July, Jupiter sets in the west around local midnight (midway between sunset and sunrise); by the month’s end, Jupiter sets some two hours earlier than local midnight.

Jupiter shines in front of the constellation Virgo, near Virgo’s sole 1st-magnitude star, called Spica.

Fernando Roquel Torres in Caguas, Puerto Rico captured Jupiter, the Great Red Spot (GRS) and all 4 of its largest moons – the Galilean satellites – on the date of Jupiter’s 2017 opposition (April 7).

If you have binoculars or a telescope, it’s fairly easy to see Jupiter’s four major moons, which look like pinpricks of light all on or near the same plane. They are often called the Galilean moons to honor Galileo, who discovered these great Jovian moons in 1610. In their order from Jupiter, these moons are Io, Europa, Ganymede and Callisto.

These moons orbit Jupiter around the Jovian equator. In cycles of six years, we view Jupiter’s equator edge-on. So, in 2015, we were able to view a number of mutual events involving Jupiter’s moons, through high-powered telescopes. Starting in late 2016, Jupiter’s axis began tilting enough toward the sun and Earth so that the farthest of these four moons, Callisto, has not been passing in front of Jupiter or behind Jupiter, as seen from our vantage point. This will continue for a period of about three years, during which time Callisto is perpetually visible to those with telescopes, alternately swinging above and below Jupiter as seen from Earth.

Click here for a Jupiter’s moons almanac, courtesy of skyandtelescope.com.

James Martin in Albuquerque, New Mexico caught this wonderful photo of Saturn on its June 15, 2017 opposition.

Let the moon guide you to the star Antares and the planet Saturn on July 5 and 6, 2017. Read more.

Saturn out nearly all night long. Saturn reached its yearly opposition on June 15. At opposition, Saturn came closest to Earth for the year, shone brightest in our sky and stayed out all night. It was highest up at midnight (midway between sunset and sunrise).

In July 2017, Saturn shines higher in the sky at nightfall than it did in June. Moreover, Saturn transits – climbs its highest point for the night – a few hours earlier than it did in June 2017. So, if you’re not a night owl, July actually presenst a better month for viewing Saturn, which is still shining at better than first-magnitude brightness.

Click here to find out Saturn’s transit time, when Saturn soars highest up for the night.

Look for Saturn above the horizon as soon as darkness falls. It’s in the southeast as seen from Earth’s Northern Hemisphere and more due east from the Southern Hemisphere. But your best view of Saturn, from either the Northern or Southern Hemisphere, is around 11 p.m. local time (midnight local daylight saving time) in early July and around 9 p.m. (10 p.m. daylight saving time) by the month’s end. That’s when Saturn climbs highest up for the night.

Be sure to let the moon guide you to Saturn (and the nearby star Antares) on July 5, July 6 and July 7.

Saturn, the farthest world that you can easily view with the eye alone, appears golden in color. It shines with a steady light.

Binoculars don’t reveal Saturn’s gorgeous rings, by the way, although binoculars will enhance Saturn’s color. To see the rings, you need a small telescope. A telescope will also reveal one or more of Saturn’s many moons, most notably Titan.

Saturn’s rings are inclined at nearly 27^o from edge-on, exhibiting their northern face. In October 2017, the rings will open most widely for this year, displaying a maximum inclination of 27^o.

As with so much in space (and on Earth), the appearance of Saturn’s rings from Earth is cyclical. In the year 2025, the rings will appear edge-on as seen from Earth. After that, we’ll begin to see the south side of Saturn’s rings, to increase to a maximum inclination of 27^o by May 2032.

Click here for recommended almanacs; they can help you know when the planets rise, transit and set in your sky.

Jenney Disimon in Sabah, Borneo captured Venus before dawn.

Let the moon guide you to Venus and the star Aldebaran on July 19, 20 and 21. Read more.

Venus, brilliant in east at morning dawn Venus is always brilliant and beautiful, the brightest celestial body to light up our sky besides the sun and moon. If you’re an early bird, you can count on Venus to be your morning companion until nearly the end of 2017.

Venus reached a milestone as the morning “star” when it swung out to its greatest elongation from the sun on June 3, 2017. At this juncture, Venus was farthest from the sun on our sky’s dome, and the telescope showed Venus as half-illuminated in sunshine, like a first quarter moon. For the rest of the year, Venus will wax toward full phase.

Click here to know Venus’s present phase, remembering to select Venus as your object of interest.

Enjoy the picturesque coupling of the waning crescent moon and Venus in the eastern sky before sunrise on July 19 and July 20.

From mid-northern latitudes (U.S. and Europe), Venus rises about two and one-half hours before the sun. By the month’s end, it’ll increase to about three hours before sunrise.

At temperate latitudes in the Southern Hemisphere (Australia and South Africa), Venus rises about three and one-half hours before sunup in early July. By the month’s end that’ll taper to about two and one-half hours.

Click here for an almanac giving rising times of Venus in your sky.

The chart below helps to illustrate why we sometimes see Venus in the evening, and sometimes before dawn.

The Earth and Venus orbit the sun counterclockwise as seen from earthly north. When Venus is to the east (left) of the Earth-sun line, we see Venus as an evening “star” in the west after sunset. After Venus reaches its inferior conjunction, Venus then moves to the west (right) of the Earth-sun line, appearing as a morning “star” in the east before sunrise.

Mars, Mercury, Earth’s moon and the dwarf planet Ceres. Mars is smaller than Earth, but bigger than our moon. Image via NASA/JPL-Caltech/UCLA.

Mars lost in the sun’s glare. Mars, though nominally an evening object, is edging closer to the sunset day by day. Mars will transition out of the evening sky and into the morning sky on July 27, 2017, at which juncture Mars will be on the far side of the sun at what astronomers call superior conjunction.

Look for Mars to emerge in the east before dawn in late September or October 2017. The conjunction of Mars and Venus on October 5, 2017, will likely present the first view of Mars in the morning sky for many skywatchers.

Exactly one year after Mars’s superior conjunction on July 27, 2017, Mars will swing to opposition on July 27, 2018. This will be Mars’s best opposition since the historically close opposition on August 28, 2003. In fact, Mars will become the fourth-brightest heavenly body to light up the sky in July 2018, after the sun, moon and the planet Venus. It’s not often that Mars outshines Jupiter, normally the four-brightest celestial object.

Wow! Wonderful shot of Mercury – over the Chilean Andes – January 2017, from Yuri Beletsky Nightscapes.

For a challenge, try to catch the young moon, the planet Mercury and the star Regulus at dusk on July 24 and 25. Binoculars could come in handy! Click here for an almanac giving you the setting time of the sun, moon and Mercury in your sky. Read more.

Mercury briefly visible after sunset. When we say Mercury is visible at only evening dusk, we’re really talking about the Northern Hemisphere. For the Southern Hemisphere, it’ll be the best evening apparition of Mercury for the year, with Mercury staying out until after nightfall at southerly latitudes. Look for Mercury low in the west, a good ways below Jupiter, as the evening twilight is giving way to nightfall.

Mercury is tricky. If you look too soon after sunset, Mercury will be obscured by evening twilight; if you look too late, it will have followed the sun beneath the horizon. Watch for Mercury low in the sky, and near the sunset point on the horizon, being mindful of Mercury’s setting time.

Throughout July, Mercury will move farther east of the setting sun day by day, and will reach its greatest eastern elongation as an evening “star” on July 30, 2017.

For a fun sky watching challenge, try to glimpse the young moon and Mercury in the western dusk on July 24 and July 25.

What do we mean by bright planet? By bright planet, we mean any solar system planet that is easily visible without an optical aid and that has been watched by our ancestors since time immemorial. In their outward order from the sun, the five bright planets are Mercury, Venus, Mars, Jupiter and Saturn. These planets actually do appear bright in our sky. They are typically as bright as – or brighter than – the brightest stars. Plus, these relatively nearby worlds tend to shine with a steadier light than the distant, twinkling stars. You can spot them, and come to know them as faithful friends, if you try.

This image is from February 8, 2016. It shows all 5 bright planets at once. Photo by our friend Eliot Herman in Tucson, Arizona.

Skywatcher, by Predrag Agatonovic.

Bottom line: In July 2017, Three of the five bright planets appear in the evening sky: Mercury, Jupiter and Saturn. Venus is found exclusively in the morning sky. Mars is lost in the sun’s glare.

Don’t miss anything. Subscribe to EarthSky News by email

Enjoy knowing where to look in the night sky? Please donate to help EarthSky keep going.

from EarthSky http://ift.tt/IJfHCr

Look for the moon near the planet Jupiter and the star Spica on June 30, July 1 and 2. Read more.

Three of the five bright planets are easy to see in July, 2017: Jupiter, Saturn and Venus. Bright Jupiter is the first “star” to pop into view at nightfall and stays out until late night. Golden Saturn is up in the east at nightfall and stays out for most of the night. Elusive Mercury is not as easy to catch after sunset, because it appears low in the west at dusk. Brilliant Venus rises before the sun, shining in front of the constellation Taurus the Bull. Red Mars, buried deep in the glare of evening twilight, cannot be seen from Earth this month. Follow the links below to learn more about the planets in July 2017.

Jupiter brightest “star” in evening sky

Saturn out nearly all night

Venus, brilliant in east at morning dawn

Mars lost in the sun’s glare

Mercury briefly visible after sunset

Like what EarthSky offers? Sign up for our free daily newsletter today!

Astronomy events, star parties, festivals, workshops

Visit a new EarthSky feature – Best Places to Stargaze – and add your fav.

Look for the moon in the vicinity of Jupiter and the nearby star Spica for several days, centered on June 28. Read more.

Jupiter brightest “star” in evening sky. Jupiter reached opposition on April 7. That is, it was opposite the sun as seen from Earth then and so was appearing in our sky all night. The giant planet came closest to Earth for 2017 one day later, on April 8. So Jupiter shone at its brightest and best in April, never fear. It’ll still be blazing away in July! Jupiter beams as the third-brightest celestial body in the nighttime sky, after the moon and Venus. In July, Jupiter shines from dusk until late evening or around midnight; meanwhile, Venus appears only before dawn.

Click here for an almanac telling you Jupiter’s setting time and Venus’ rising time in your sky.

Watch for the moon to join up with Jupiter for several days, centered on or near July 28. See the above sky chart. Wonderful sight!

From the Northern Hemisphere, Jupiter appears in the southwestern sky first thing at dusk; and from the Southern Hemisphere, Jupiter appears high overhead at dusk or nightfall. From all of Earth, Jupiter sinks in a westerly direction throughout the night, as Earth spins under the sky. In early July, Jupiter sets in the west around local midnight (midway between sunset and sunrise); by the month’s end, Jupiter sets some two hours earlier than local midnight.

Jupiter shines in front of the constellation Virgo, near Virgo’s sole 1st-magnitude star, called Spica.

Fernando Roquel Torres in Caguas, Puerto Rico captured Jupiter, the Great Red Spot (GRS) and all 4 of its largest moons – the Galilean satellites – on the date of Jupiter’s 2017 opposition (April 7).

If you have binoculars or a telescope, it’s fairly easy to see Jupiter’s four major moons, which look like pinpricks of light all on or near the same plane. They are often called the Galilean moons to honor Galileo, who discovered these great Jovian moons in 1610. In their order from Jupiter, these moons are Io, Europa, Ganymede and Callisto.

These moons orbit Jupiter around the Jovian equator. In cycles of six years, we view Jupiter’s equator edge-on. So, in 2015, we were able to view a number of mutual events involving Jupiter’s moons, through high-powered telescopes. Starting in late 2016, Jupiter’s axis began tilting enough toward the sun and Earth so that the farthest of these four moons, Callisto, has not been passing in front of Jupiter or behind Jupiter, as seen from our vantage point. This will continue for a period of about three years, during which time Callisto is perpetually visible to those with telescopes, alternately swinging above and below Jupiter as seen from Earth.

Click here for a Jupiter’s moons almanac, courtesy of skyandtelescope.com.

James Martin in Albuquerque, New Mexico caught this wonderful photo of Saturn on its June 15, 2017 opposition.

Let the moon guide you to the star Antares and the planet Saturn on July 5 and 6, 2017. Read more.

Saturn out nearly all night long. Saturn reached its yearly opposition on June 15. At opposition, Saturn came closest to Earth for the year, shone brightest in our sky and stayed out all night. It was highest up at midnight (midway between sunset and sunrise).

In July 2017, Saturn shines higher in the sky at nightfall than it did in June. Moreover, Saturn transits – climbs its highest point for the night – a few hours earlier than it did in June 2017. So, if you’re not a night owl, July actually presenst a better month for viewing Saturn, which is still shining at better than first-magnitude brightness.

Click here to find out Saturn’s transit time, when Saturn soars highest up for the night.

Look for Saturn above the horizon as soon as darkness falls. It’s in the southeast as seen from Earth’s Northern Hemisphere and more due east from the Southern Hemisphere. But your best view of Saturn, from either the Northern or Southern Hemisphere, is around 11 p.m. local time (midnight local daylight saving time) in early July and around 9 p.m. (10 p.m. daylight saving time) by the month’s end. That’s when Saturn climbs highest up for the night.

Be sure to let the moon guide you to Saturn (and the nearby star Antares) on July 5, July 6 and July 7.

Saturn, the farthest world that you can easily view with the eye alone, appears golden in color. It shines with a steady light.

Binoculars don’t reveal Saturn’s gorgeous rings, by the way, although binoculars will enhance Saturn’s color. To see the rings, you need a small telescope. A telescope will also reveal one or more of Saturn’s many moons, most notably Titan.

Saturn’s rings are inclined at nearly 27^o from edge-on, exhibiting their northern face. In October 2017, the rings will open most widely for this year, displaying a maximum inclination of 27^o.

As with so much in space (and on Earth), the appearance of Saturn’s rings from Earth is cyclical. In the year 2025, the rings will appear edge-on as seen from Earth. After that, we’ll begin to see the south side of Saturn’s rings, to increase to a maximum inclination of 27^o by May 2032.

Click here for recommended almanacs; they can help you know when the planets rise, transit and set in your sky.

Jenney Disimon in Sabah, Borneo captured Venus before dawn.

Let the moon guide you to Venus and the star Aldebaran on July 19, 20 and 21. Read more.

Venus, brilliant in east at morning dawn Venus is always brilliant and beautiful, the brightest celestial body to light up our sky besides the sun and moon. If you’re an early bird, you can count on Venus to be your morning companion until nearly the end of 2017.

Venus reached a milestone as the morning “star” when it swung out to its greatest elongation from the sun on June 3, 2017. At this juncture, Venus was farthest from the sun on our sky’s dome, and the telescope showed Venus as half-illuminated in sunshine, like a first quarter moon. For the rest of the year, Venus will wax toward full phase.

Click here to know Venus’s present phase, remembering to select Venus as your object of interest.

Enjoy the picturesque coupling of the waning crescent moon and Venus in the eastern sky before sunrise on July 19 and July 20.

From mid-northern latitudes (U.S. and Europe), Venus rises about two and one-half hours before the sun. By the month’s end, it’ll increase to about three hours before sunrise.

At temperate latitudes in the Southern Hemisphere (Australia and South Africa), Venus rises about three and one-half hours before sunup in early July. By the month’s end that’ll taper to about two and one-half hours.

Click here for an almanac giving rising times of Venus in your sky.

The chart below helps to illustrate why we sometimes see Venus in the evening, and sometimes before dawn.

The Earth and Venus orbit the sun counterclockwise as seen from earthly north. When Venus is to the east (left) of the Earth-sun line, we see Venus as an evening “star” in the west after sunset. After Venus reaches its inferior conjunction, Venus then moves to the west (right) of the Earth-sun line, appearing as a morning “star” in the east before sunrise.

Mars, Mercury, Earth’s moon and the dwarf planet Ceres. Mars is smaller than Earth, but bigger than our moon. Image via NASA/JPL-Caltech/UCLA.

Mars lost in the sun’s glare. Mars, though nominally an evening object, is edging closer to the sunset day by day. Mars will transition out of the evening sky and into the morning sky on July 27, 2017, at which juncture Mars will be on the far side of the sun at what astronomers call superior conjunction.

Look for Mars to emerge in the east before dawn in late September or October 2017. The conjunction of Mars and Venus on October 5, 2017, will likely present the first view of Mars in the morning sky for many skywatchers.

Exactly one year after Mars’s superior conjunction on July 27, 2017, Mars will swing to opposition on July 27, 2018. This will be Mars’s best opposition since the historically close opposition on August 28, 2003. In fact, Mars will become the fourth-brightest heavenly body to light up the sky in July 2018, after the sun, moon and the planet Venus. It’s not often that Mars outshines Jupiter, normally the four-brightest celestial object.

Wow! Wonderful shot of Mercury – over the Chilean Andes – January 2017, from Yuri Beletsky Nightscapes.

For a challenge, try to catch the young moon, the planet Mercury and the star Regulus at dusk on July 24 and 25. Binoculars could come in handy! Click here for an almanac giving you the setting time of the sun, moon and Mercury in your sky. Read more.

Mercury briefly visible after sunset. When we say Mercury is visible at only evening dusk, we’re really talking about the Northern Hemisphere. For the Southern Hemisphere, it’ll be the best evening apparition of Mercury for the year, with Mercury staying out until after nightfall at southerly latitudes. Look for Mercury low in the west, a good ways below Jupiter, as the evening twilight is giving way to nightfall.

Mercury is tricky. If you look too soon after sunset, Mercury will be obscured by evening twilight; if you look too late, it will have followed the sun beneath the horizon. Watch for Mercury low in the sky, and near the sunset point on the horizon, being mindful of Mercury’s setting time.

Throughout July, Mercury will move farther east of the setting sun day by day, and will reach its greatest eastern elongation as an evening “star” on July 30, 2017.

For a fun sky watching challenge, try to glimpse the young moon and Mercury in the western dusk on July 24 and July 25.

What do we mean by bright planet? By bright planet, we mean any solar system planet that is easily visible without an optical aid and that has been watched by our ancestors since time immemorial. In their outward order from the sun, the five bright planets are Mercury, Venus, Mars, Jupiter and Saturn. These planets actually do appear bright in our sky. They are typically as bright as – or brighter than – the brightest stars. Plus, these relatively nearby worlds tend to shine with a steadier light than the distant, twinkling stars. You can spot them, and come to know them as faithful friends, if you try.

This image is from February 8, 2016. It shows all 5 bright planets at once. Photo by our friend Eliot Herman in Tucson, Arizona.

Skywatcher, by Predrag Agatonovic.

Bottom line: In July 2017, Three of the five bright planets appear in the evening sky: Mercury, Jupiter and Saturn. Venus is found exclusively in the morning sky. Mars is lost in the sun’s glare.

Don’t miss anything. Subscribe to EarthSky News by email

Enjoy knowing where to look in the night sky? Please donate to help EarthSky keep going.

from EarthSky http://ift.tt/IJfHCr

Trump fact check: Climate policy benefits vastly exceed costs

When people who benefit from maintaining the status quo argue against climate policies, they invariably use two misleading tactics: exaggerating the costs of climate policies, and ignoring their benefits—economic and otherwise. In justifying his historically irresponsible decision to withdraw America from the Paris Agreement on climate change, President Trump followed this same playbook, falsely claiming: “The cost to the economy at this time would be close to $3 trillion in lost GDP [gross domestic product].”

That statistic originated from a report by National Economic Research Associates, Inc., which explicitly notes that it “does not take into account potential benefits from avoided emissions. The study results are not a benefit-cost analysis of climate change.” As Yale economistKenneth Gillingham noted, the report’s cost estimates are also based on one specific set of policy actions that the United States could implement to meet its Paris pledges. But there’s an infinite combination of possible climate policy responses, with some costing more than others.

For example, a revenue-neutral carbon tax is the proposed policy that currently has the most widespread support. One such proposal by the Climate Leadership Council has been endorsed by a broad coalition that includes Stephen Hawking, ExxonMobil, the Nature Conservancy, and George Shultz. And the Citizens’ Climate Lobby—a nonpartisan grassroots organization advocating for a similar policy—recently sent over 1,000 volunteers to lobby members of Congress in Washington, DC.

Regional Economic Modeling, Inc. (REMI) evaluated how the Citizens’ Climate Lobby’s proposed policy would impact the US economy. The REMI report concluded that implementing a rising price on carbon pollution and returning 100 percent of the revenue equally to American taxpayers would grow the economy and modestly increase personal disposable income, employment, and gross domestic product—the total of all goods and services produced within a nation’s borders. And the REMI report didn’t even include the financial benefits of slowing climate change and curbing its harmful economic impacts.

Those benefits are potentially massive. In terms of climate change, many of the benefits are realized in avoided costs. For example, the 2006 Stern Review on the Economics of Climate Change found that unabated climate change would cost the world 5 to 20 percent of GDP by 2100. The economic picture could be even bleaker yet—most economic modeling assumes that economic growth will continue steadily regardless of climate change, but in reality, climate impacts are likely to slow economic growth. That was the finding of two papers published in 2015 by researchers from Stanford and the University of California at Berkeley.

The second paper found that there’s a sweet spot average temperature of around 13 degrees Celsius (55 degrees Fahrenheit) at which economic productivity is highest. The United States and much of Europe currently have climates in that optimal range, but many countries near the equator—which happen to predominantly be poorer, developing countries—already have temperatures above the sweet spot. As global warming causes temperatures to rise, the climates of the United States and Europe will slip out of the economically optimal temperature range, and that same temperature rise will push those poorer countries even further into the realm of economy-crippling heat. As a result, global warming will hamper economic growth. The researchers estimated that this would amplify the costs of climate change by at least 2.5 times more than previous estimates.

Tackling global warming will certainly come with costs. Although a revenue-neutral carbon tax would benefit the economy, that one policy by itself won’t be enough to solve the problem. We would still need to invest in and deploy low-carbon technologies like renewable energy and electric vehicles. However, looking at those costs in isolation without considering their benefits, as President Trump did, paints a misleading and inaccurate picture.

For example, Citibank—America’s third-largest bank—published a report in 2015 looking at both the costs and benefits of climate action and inaction scenarios. The report found that inaction actually had higher investment costs than the action scenario—such as cost-saving investments in energy efficiency, for example. 

Click here to read the rest

from Skeptical Science http://ift.tt/2sZsP5x

When people who benefit from maintaining the status quo argue against climate policies, they invariably use two misleading tactics: exaggerating the costs of climate policies, and ignoring their benefits—economic and otherwise. In justifying his historically irresponsible decision to withdraw America from the Paris Agreement on climate change, President Trump followed this same playbook, falsely claiming: “The cost to the economy at this time would be close to $3 trillion in lost GDP [gross domestic product].”

That statistic originated from a report by National Economic Research Associates, Inc., which explicitly notes that it “does not take into account potential benefits from avoided emissions. The study results are not a benefit-cost analysis of climate change.” As Yale economistKenneth Gillingham noted, the report’s cost estimates are also based on one specific set of policy actions that the United States could implement to meet its Paris pledges. But there’s an infinite combination of possible climate policy responses, with some costing more than others.

For example, a revenue-neutral carbon tax is the proposed policy that currently has the most widespread support. One such proposal by the Climate Leadership Council has been endorsed by a broad coalition that includes Stephen Hawking, ExxonMobil, the Nature Conservancy, and George Shultz. And the Citizens’ Climate Lobby—a nonpartisan grassroots organization advocating for a similar policy—recently sent over 1,000 volunteers to lobby members of Congress in Washington, DC.

Regional Economic Modeling, Inc. (REMI) evaluated how the Citizens’ Climate Lobby’s proposed policy would impact the US economy. The REMI report concluded that implementing a rising price on carbon pollution and returning 100 percent of the revenue equally to American taxpayers would grow the economy and modestly increase personal disposable income, employment, and gross domestic product—the total of all goods and services produced within a nation’s borders. And the REMI report didn’t even include the financial benefits of slowing climate change and curbing its harmful economic impacts.

Those benefits are potentially massive. In terms of climate change, many of the benefits are realized in avoided costs. For example, the 2006 Stern Review on the Economics of Climate Change found that unabated climate change would cost the world 5 to 20 percent of GDP by 2100. The economic picture could be even bleaker yet—most economic modeling assumes that economic growth will continue steadily regardless of climate change, but in reality, climate impacts are likely to slow economic growth. That was the finding of two papers published in 2015 by researchers from Stanford and the University of California at Berkeley.

The second paper found that there’s a sweet spot average temperature of around 13 degrees Celsius (55 degrees Fahrenheit) at which economic productivity is highest. The United States and much of Europe currently have climates in that optimal range, but many countries near the equator—which happen to predominantly be poorer, developing countries—already have temperatures above the sweet spot. As global warming causes temperatures to rise, the climates of the United States and Europe will slip out of the economically optimal temperature range, and that same temperature rise will push those poorer countries even further into the realm of economy-crippling heat. As a result, global warming will hamper economic growth. The researchers estimated that this would amplify the costs of climate change by at least 2.5 times more than previous estimates.

Tackling global warming will certainly come with costs. Although a revenue-neutral carbon tax would benefit the economy, that one policy by itself won’t be enough to solve the problem. We would still need to invest in and deploy low-carbon technologies like renewable energy and electric vehicles. However, looking at those costs in isolation without considering their benefits, as President Trump did, paints a misleading and inaccurate picture.

For example, Citibank—America’s third-largest bank—published a report in 2015 looking at both the costs and benefits of climate action and inaction scenarios. The report found that inaction actually had higher investment costs than the action scenario—such as cost-saving investments in energy efficiency, for example. 

Click here to read the rest

from Skeptical Science http://ift.tt/2sZsP5x

Navy Divers Stand Watch during International Submarine Races

Students test their science and technology skills underwater while Navy divers keep them safe.

from http://ift.tt/2u6m4gR

Students test their science and technology skills underwater while Navy divers keep them safe.

from http://ift.tt/2u6m4gR

Virtual Reality Stimulates Learning for Children of Wounded Warriors

The children of wounded warriors got the chance to learn how virtual and augmented reality innovations may someday improve the quality of life for their parents.

from http://ift.tt/2t86TmZ

The children of wounded warriors got the chance to learn how virtual and augmented reality innovations may someday improve the quality of life for their parents.

from http://ift.tt/2t86TmZ

Top 10 things to know about asteroids

Illustration of an asteroid passing near the Earth. Image via NASA.

In honor of International Asteroid Day today (June 30, 2017), NASA put together this list of 10 cool facts about asteroids that you might not know.

1. A place in space. Asteroids—named by British astronomer William Herschel from the Greek expression meaning “star-like”—are rocky, airless worlds that are too small to be called planets. But what they might lack in size they certainly make up for in number: An estimated 1.1 to 1.9 million asteroids larger than 1 kilometer are in the Main Belt between the orbits of Mars and Jupiter. And there are millions more that are smaller in size. Asteroids range in size from Vesta—the largest at about 329 miles (529 kilometers) wide—to bodies that are just a few feet across.

2. What lies beneath. Asteroids are generally categorized into three types: carbon-rich, silicate, or metallic, or some combination of the three. Why the different types? It all comes down to how far from the sun they formed. Some experienced high temperatures and partly melted, with iron sinking to the center and volcanic lava forced to the surface. The asteroid Vesta is one example we know of today.

The asteroid Eros as photographed by the NEAR Shoemaker spacecraft from an orbital altitude of about 200 kilometers (124 miles). Image via NASA.

3. Small overall. If all of the asteroids were combined into a ball, they would still be much smaller than the Earth’s moon.

4. Except for a big one. In 1801, Giuseppe Piazzi discovered the first and largest asteroid, Ceres, orbiting between Mars and Jupiter. Ceres is so large that it encompasses about one-fourth of the estimated total mass of all the asteroids in the asteroid belt. Today, it’s classified as a dwarf planet.

Enhanced-color view of Ceres. The largest object in the asteroid belt, Ceres is now classified as a dwarf planet. Image via NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

5. Mission to a metal world. NASA’s Psyche mission will launch in 2022 to explore an all-metal asteroid—what could be the core of an early planet—for the very first time. And in October 2021, the Lucy mission will be the first to visit Jupiter’s swarms of Trojan asteroids.

6. Near-Earth asteroids. The term ‘near’ in near-Earth asteroid is actually a misnomer; most of these bodies do not come close to Earth at all. By definition, a near-Earth asteroid is an asteroid that comes within 28 million miles (44 million km) of Earth’s orbit. As of June 19, 2017, there are 16,209 known near-Earth asteroids, with 1,803 classified as potentially hazardous asteroids (those that could someday pose a threat to Earth).

7. Comin’ in hot. About once a year, a car-sized asteroid hits Earth’s atmosphere, creates an impressive fireball, and burns up before reaching the surface.

8. But we’re keeping an eye out. Ground-based observatories and facilities such Pan-STARRS, the Catalina Sky Survey, and ATLAS are constantly on the hunt to detect near-Earth asteroids. NASA also has a small infrared observatory in orbit about the Earth: NEOWISE. In addition to detecting asteroids and comets, NEOWISE also characterizes these small bodies.

9. Buddy system. Roughly one-sixth of the asteroid population have a small companion moon (some even have two moons). The first discovery of an asteroid-moon system was of asteroid Ida and its moon Dactyl in 1993.

10. Earthly visitors. Several NASA space missions have flown and observed asteroids. The NEAR Shoemaker mission landed on asteroid Eros in 2001 and NASA’s Dawn mission was the first mission to orbit an asteroid in 2011. In 2005, the Japanese spacecraft Hayabusa landed on asteroid Itokawa. Currently, NASA’s OSIRIS-REx is en route to a near-Earth asteroid called Bennu; it will bring a small sample back to Earth for study.

NASA has more asteroid info here.

Read more from NASA

Bottom line: 10 facts about asteroids from NASA.

from EarthSky http://ift.tt/2sXM6nO

Illustration of an asteroid passing near the Earth. Image via NASA.

In honor of International Asteroid Day today (June 30, 2017), NASA put together this list of 10 cool facts about asteroids that you might not know.

1. A place in space. Asteroids—named by British astronomer William Herschel from the Greek expression meaning “star-like”—are rocky, airless worlds that are too small to be called planets. But what they might lack in size they certainly make up for in number: An estimated 1.1 to 1.9 million asteroids larger than 1 kilometer are in the Main Belt between the orbits of Mars and Jupiter. And there are millions more that are smaller in size. Asteroids range in size from Vesta—the largest at about 329 miles (529 kilometers) wide—to bodies that are just a few feet across.

2. What lies beneath. Asteroids are generally categorized into three types: carbon-rich, silicate, or metallic, or some combination of the three. Why the different types? It all comes down to how far from the sun they formed. Some experienced high temperatures and partly melted, with iron sinking to the center and volcanic lava forced to the surface. The asteroid Vesta is one example we know of today.

The asteroid Eros as photographed by the NEAR Shoemaker spacecraft from an orbital altitude of about 200 kilometers (124 miles). Image via NASA.

3. Small overall. If all of the asteroids were combined into a ball, they would still be much smaller than the Earth’s moon.

4. Except for a big one. In 1801, Giuseppe Piazzi discovered the first and largest asteroid, Ceres, orbiting between Mars and Jupiter. Ceres is so large that it encompasses about one-fourth of the estimated total mass of all the asteroids in the asteroid belt. Today, it’s classified as a dwarf planet.

Enhanced-color view of Ceres. The largest object in the asteroid belt, Ceres is now classified as a dwarf planet. Image via NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

5. Mission to a metal world. NASA’s Psyche mission will launch in 2022 to explore an all-metal asteroid—what could be the core of an early planet—for the very first time. And in October 2021, the Lucy mission will be the first to visit Jupiter’s swarms of Trojan asteroids.

6. Near-Earth asteroids. The term ‘near’ in near-Earth asteroid is actually a misnomer; most of these bodies do not come close to Earth at all. By definition, a near-Earth asteroid is an asteroid that comes within 28 million miles (44 million km) of Earth’s orbit. As of June 19, 2017, there are 16,209 known near-Earth asteroids, with 1,803 classified as potentially hazardous asteroids (those that could someday pose a threat to Earth).

7. Comin’ in hot. About once a year, a car-sized asteroid hits Earth’s atmosphere, creates an impressive fireball, and burns up before reaching the surface.

8. But we’re keeping an eye out. Ground-based observatories and facilities such Pan-STARRS, the Catalina Sky Survey, and ATLAS are constantly on the hunt to detect near-Earth asteroids. NASA also has a small infrared observatory in orbit about the Earth: NEOWISE. In addition to detecting asteroids and comets, NEOWISE also characterizes these small bodies.

9. Buddy system. Roughly one-sixth of the asteroid population have a small companion moon (some even have two moons). The first discovery of an asteroid-moon system was of asteroid Ida and its moon Dactyl in 1993.

10. Earthly visitors. Several NASA space missions have flown and observed asteroids. The NEAR Shoemaker mission landed on asteroid Eros in 2001 and NASA’s Dawn mission was the first mission to orbit an asteroid in 2011. In 2005, the Japanese spacecraft Hayabusa landed on asteroid Itokawa. Currently, NASA’s OSIRIS-REx is en route to a near-Earth asteroid called Bennu; it will bring a small sample back to Earth for study.

NASA has more asteroid info here.

Read more from NASA

Bottom line: 10 facts about asteroids from NASA.

from EarthSky http://ift.tt/2sXM6nO

Where’s the moon? 1st quarter

Our friend Patrick Casaert of the Facebook page La Lune The Moon caught the moon on May 1, 2017, when it was nearly 1st quarter.

The moon reaches its first quarter phase on July 1, 2017 at 0:51 UTC. At North American time zones, the moon’s first quarter phase happens on June 30, at 9:51 p.m ADT, 8:51 p.m. EDT, 7:51 p.m. CDT, 6:51 p.m. MDT 5:51 p.m. PDT and 4:51 p.m. AKDT.

A first quarter moon shows half of its lighted hemisphere – half of its day side – to Earth.

The Earth and moon are like mirrors to each other. If you were on the moon tonight, you’d see a last quarter Earth. Simulation of last quarter Earth as viewed from 1st quarter moon (2017 July 1 at 0:51 UTC). The terminator or shadow line represents Earth’s line of sunsets. Image via Fourmilab.

There will be a magnificent pairing of the first quarter moon and Jupiter as darkness falls on June 30. This planet ended its retrograde motion on June 10 and is now past its best time for viewing in 2017. But it’s the biggest planet in our solar system, and still dazzlingly bright!

Watch for the first quarter moon and Jupiter on June 30, 2017. Read more.

At quarter moon, the moon’s disk is half-illuminated by sunlight and half-immersed in the moon’s own shadow.

We call this moon a quarter and not a half because it is one quarter of the way around in its orbit of Earth, as measured from one new moon to the next. Also, although a first quarter moon appears half-lit to us, the illuminated portion we see of a first quarter moon truly is just a quarter. We’re now seeing half the moon’s day side, that is. Another lighted quarter of the moon shines just as brightly in the direction opposite Earth!

Here’s what a first quarter moon looks like. The terminator line – or line between light and dark on the moon – appears straight. Aqilla Othman in Port Dickson, Negeri Sembilan, Malaysia caught this photo on May 3, 2017. Notice that he caught Lunar X and Lunar V.

Here’s a closer look at Lunar X and Lunar V. Photo taken May 3, 2017 by Izaty Liyana in Port Dickson, Negeri Sembilan, Malaysia. What is Lunar X?

And what about the term half moon? That’s a beloved term, but not an official one.

A first quarter moon rises at noon and is highest in the sky at sunset. It sets around midnight. First quarter moon comes a week after new moon. Now, as seen from above, the moon in its orbit around Earth is at right angles to a line between the Earth and sun.

As the moon orbits Earth, it changes phase in an orderly way. Follow these links to understand the various phases of the moon.

Four keys to understanding moon phases

Where’s the moon? Waxing crescent
Where’s the moon? First quarter
Where’s the moon? Waxing gibbous
What’s special about a full moon?
Where’s the moon? Waning gibbous
Where’s the moon? Last quarter
Where’s the moon? Waning crescent
Where’s the moon? New phase

from EarthSky http://ift.tt/1GsHF3c

Our friend Patrick Casaert of the Facebook page La Lune The Moon caught the moon on May 1, 2017, when it was nearly 1st quarter.

The moon reaches its first quarter phase on July 1, 2017 at 0:51 UTC. At North American time zones, the moon’s first quarter phase happens on June 30, at 9:51 p.m ADT, 8:51 p.m. EDT, 7:51 p.m. CDT, 6:51 p.m. MDT 5:51 p.m. PDT and 4:51 p.m. AKDT.

A first quarter moon shows half of its lighted hemisphere – half of its day side – to Earth.

The Earth and moon are like mirrors to each other. If you were on the moon tonight, you’d see a last quarter Earth. Simulation of last quarter Earth as viewed from 1st quarter moon (2017 July 1 at 0:51 UTC). The terminator or shadow line represents Earth’s line of sunsets. Image via Fourmilab.

There will be a magnificent pairing of the first quarter moon and Jupiter as darkness falls on June 30. This planet ended its retrograde motion on June 10 and is now past its best time for viewing in 2017. But it’s the biggest planet in our solar system, and still dazzlingly bright!

Watch for the first quarter moon and Jupiter on June 30, 2017. Read more.

At quarter moon, the moon’s disk is half-illuminated by sunlight and half-immersed in the moon’s own shadow.

We call this moon a quarter and not a half because it is one quarter of the way around in its orbit of Earth, as measured from one new moon to the next. Also, although a first quarter moon appears half-lit to us, the illuminated portion we see of a first quarter moon truly is just a quarter. We’re now seeing half the moon’s day side, that is. Another lighted quarter of the moon shines just as brightly in the direction opposite Earth!

Here’s what a first quarter moon looks like. The terminator line – or line between light and dark on the moon – appears straight. Aqilla Othman in Port Dickson, Negeri Sembilan, Malaysia caught this photo on May 3, 2017. Notice that he caught Lunar X and Lunar V.

Here’s a closer look at Lunar X and Lunar V. Photo taken May 3, 2017 by Izaty Liyana in Port Dickson, Negeri Sembilan, Malaysia. What is Lunar X?

And what about the term half moon? That’s a beloved term, but not an official one.

A first quarter moon rises at noon and is highest in the sky at sunset. It sets around midnight. First quarter moon comes a week after new moon. Now, as seen from above, the moon in its orbit around Earth is at right angles to a line between the Earth and sun.

As the moon orbits Earth, it changes phase in an orderly way. Follow these links to understand the various phases of the moon.

Four keys to understanding moon phases

Where’s the moon? Waxing crescent
Where’s the moon? First quarter
Where’s the moon? Waxing gibbous
What’s special about a full moon?
Where’s the moon? Waning gibbous
Where’s the moon? Last quarter
Where’s the moon? Waning crescent
Where’s the moon? New phase

from EarthSky http://ift.tt/1GsHF3c

Today in science: Tunguska explosion

Fallen trees at Tunguska. This image is from 1927, when Russian scientists were finally able to get to the scene. Photograph from the Soviet Academy of Science 1927 expedition led by Leonid Kulik.

June 30, 1908 In a remote part of Russia, a fireball was seen streaking across the daytime sky. Within moments, something exploded in the atmosphere above Siberia’s Podkamennaya Tunguska River in what is now Krasnoyarsk Krai, Russia.

This event – now widely known as the Tunguska event – is believed to have been caused by an incoming asteroid (or comet), which never actually struck Earth but instead exploded in the atmosphere, causing what is known as an air burst, three to six miles (5–10 kilometers) above Earth’s surface.

The explosion released enough energy to kill reindeer and flatten trees for many kilometers around the blast site. But no crater was ever found.

At the time, it was difficult to reach this remote part of Siberia. It wasn’t until 1927 that Leonid Kulik led the first Soviet research expedition to investigate the Tunguska event. He made a initial trip to the region, interviewed local witnesses and explored the region where the trees had been felled. He became convinced that they were all turned with their roots to the center. He did not find any meteorite fragments, and he did not find a meteorite crater.

Map showing the approximate location of the Tunguska event of 1908.

Over the years, scientists and others concocted fabulous explanations for the Tunguska explosion. Some were pretty wild – such as the encounter of Earth with an alien spacecraft, or a mini-black-hole, or a particle of antimatter.

The truth is much more ordinary. In all likelihood, a small icy comet or stony asteroid collided with Earth’s atmosphere on June 30, 1908. If it were an asteroid, it might have been about a third as big as a football field – moving at about 15 kilometers (10 miles) per second.

Because the explosion took place so long ago, we might never know for certain whether it was an asteroid or comet. But in recent decades astronomers have come to take the possibility of comet and asteroid impacts more seriously. They now have regular observing programs to watch for Near-Earth Objects, as they’re called. They also meet regularly to discuss what might happen if we did find an object on a collision course with Earth.

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

Photo of an air burst, in this case from a U.S. Navy submarine-launched Tomamhawk cruise missile. An air burst from an incoming comet or asteroid is thought to have flattened trees in Siberia in 1908. Image via Wikimedia Commons

Bottom line: On June 30, 1908, an object from space apparently exploded in the atmosphere above Siberia. The explosion killed reindeer and flattened trees, in what has become known as the Tunguska event.

from EarthSky http://ift.tt/Y6G1jA

Fallen trees at Tunguska. This image is from 1927, when Russian scientists were finally able to get to the scene. Photograph from the Soviet Academy of Science 1927 expedition led by Leonid Kulik.

June 30, 1908 In a remote part of Russia, a fireball was seen streaking across the daytime sky. Within moments, something exploded in the atmosphere above Siberia’s Podkamennaya Tunguska River in what is now Krasnoyarsk Krai, Russia.

This event – now widely known as the Tunguska event – is believed to have been caused by an incoming asteroid (or comet), which never actually struck Earth but instead exploded in the atmosphere, causing what is known as an air burst, three to six miles (5–10 kilometers) above Earth’s surface.

The explosion released enough energy to kill reindeer and flatten trees for many kilometers around the blast site. But no crater was ever found.

At the time, it was difficult to reach this remote part of Siberia. It wasn’t until 1927 that Leonid Kulik led the first Soviet research expedition to investigate the Tunguska event. He made a initial trip to the region, interviewed local witnesses and explored the region where the trees had been felled. He became convinced that they were all turned with their roots to the center. He did not find any meteorite fragments, and he did not find a meteorite crater.

Map showing the approximate location of the Tunguska event of 1908.

Over the years, scientists and others concocted fabulous explanations for the Tunguska explosion. Some were pretty wild – such as the encounter of Earth with an alien spacecraft, or a mini-black-hole, or a particle of antimatter.

The truth is much more ordinary. In all likelihood, a small icy comet or stony asteroid collided with Earth’s atmosphere on June 30, 1908. If it were an asteroid, it might have been about a third as big as a football field – moving at about 15 kilometers (10 miles) per second.

Because the explosion took place so long ago, we might never know for certain whether it was an asteroid or comet. But in recent decades astronomers have come to take the possibility of comet and asteroid impacts more seriously. They now have regular observing programs to watch for Near-Earth Objects, as they’re called. They also meet regularly to discuss what might happen if we did find an object on a collision course with Earth.

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

Photo of an air burst, in this case from a U.S. Navy submarine-launched Tomamhawk cruise missile. An air burst from an incoming comet or asteroid is thought to have flattened trees in Siberia in 1908. Image via Wikimedia Commons

Bottom line: On June 30, 1908, an object from space apparently exploded in the atmosphere above Siberia. The explosion killed reindeer and flattened trees, in what has become known as the Tunguska event.

from EarthSky http://ift.tt/Y6G1jA