Archive for July, 2013

NASA Image of the Day – July 12, 2013

July 12, 2013 Leave a comment

NASA Image of the Day - July 12, 2013

This image shows the Mars Science Laboratory – more commonly known as the Curiosity rover – heading toward Mount Sharp on the 329th day (“sol”) of its mission to the Red Planet. Mount Sharp is about eight kilometers to the southwest of Curiosity’s location in this image. If you look carefully, you can see some of the scientific investigation tools used by the rover. For example, a rock-sampling drill appears in the lower left corner of the image. Image courtesy NASA/Jet Propulsion Laboratory-California Institute of Technology.

NOAA: May 2013 third-hottest on record

July 12, 2013 Leave a comment

May 2013 was hot in much of the world. The National Oceanic & Atmospheric Administration said recently that it was, in fact, the third-warmest May since record-keeping began in 1880. Only May 1998 and May 2005 were warmer.

NOAA was quite specific about the situation in May. The agency announced that “[t]he global land surface temperature was 1.11°C (2.00°F) above the 20th century average of 11.1°C (52.0°F), also the third warmest May on record.”

The situation at sea was not much better. “For the ocean,” according to NOAA, “the May global sea surface temperature was 0.49°C (0.88°F) above the 20th century average of 16.3°C (61.3°F), tying with 2003 and 2009 as the fifth warmest May on record.”

Here in the United States, the central and southeastern regions had a cooler-than-average May. So did Alaska. Regions that experienced higher than average temperatures were northern Siberia, western Russia, northern and eastern Europe, and central Australia.


Graphic courtesy NOAA Environmental Visualization Laboratory.

Categories: climate change Tags: ,

NASA Image of the Day – July 10, 2013

July 12, 2013 Leave a comment

NASA Image of the Day - July 10, 2013

This image of Tropical Storm Chantal was obtained by the satellite known as GOES-West. Photo courtesy NOAA/NASA GOES Project.

New Horizons probe sends back image of Pluto’s moon Charon

July 12, 2013 Leave a comment

The New Horizons spacecraft won’t arrive in the vicinity of Pluto until 2015, but it is close enough now to obtain images of some Kuiper Belt objects.

NASA has released images of Charon, Pluto’s largest moon, taken by New Horizons earlier this month. The images of Charon are somewhat fuzzy because the spacecraft is still about 550 million miles (900 million kilometers) away from Pluto, which is farther away from the dwarf planet than Earth is from Jupiter. From the perspective of the spacecraft, Charon’s location is about 0.01 degrees from Pluto.

Nevertheless, the detail they provide about Charon is a significant improvement over that obtained from Earth-based observation.

“The image itself might not look very impressive to the untrained eye, but compared to the discovery images of Charon from Earth, these ‘discovery’ images from New Horizons look great!”, Hal Weaver, a New Horizons project scientist affiliated with The Johns Hopkins University Applied Physics Laboratory said. “We’re very excited to see Pluto and Charon as separate objects for the first time from New Horizons.”

The photographs were obtained by the spacecraft’s Long Range Reconnaissance Imager in less than one second.

Charon is not Pluto’s only satellite. However, the images obtained by LORRI (an acronym for New Horizons’ photographic apparatus) indicate just how tiny the other moons of Pluto are. Pluto is about 2,300 kilometers across and Charon is about half that large (1,200 kilometers). None of the other moons of Pluto exceed about 170 kilometers across. Some may be as small as 10 kilometers (that’s about 6.2 miles) across!


This composite image of Charon is an amalgamation of six images. Pluto is the bright object near the center of the frame, while Charon is the dimmer object to the upper left of Pluto. Image courtesy NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.

New Horizons is beyond the orbit of Uranus and is traveling at a velocity of about 15 kilometers per second. That’s about 32,000 miles per hour! Despite that amazing speed, the spacecraft won’t arrive at Pluto until July 2015. By the time it gets there it will have been traveling in the cosmos for about nine and one-half years.

If that causes you to wonder just how big the solar system is, it should. Think of it this way: the solar system is so enormous that even the two Voyager spacecraft that were launched 36 years ago, which are still moving as fast as New Horizons is, have not yet left it.

NASA’s Image of the Day – July 9, 2013

NASA's Image of the Day - July 13, 2013

One of the Expedition 36 crew members aboard the International Space Station used a 50mm lens to record this image of a large mass of storm clouds over the Atlantic Ocean near Brazil and the Equator on July 4, 2013. A Russian spacecraft, docked to the orbiting outpost, partially covers a small patch of sunglint on the ocean waters in a break in the clouds. Photo courtesy NASA.

July is a great month for planetwatching!

The night sky this month is a showcase of the solar system’s planets, with five of them available for your viewing before August arrives.

Venus and Saturn are visible in the evening sky all month, while Mars and Jupiter will present a fantastic image when they reach conjunction in the early morning sky on July 22. If you are an early riser, you’ll be able to see Mercury in the pre-dawn hours by late in the month.

Venus rises at dusk and will be visible until about one and one-half hours after sunset. Look for it in the western sky, above and to the right of the moon. As sunset approaches, Venus will drop lower than the moon on the horizon.

Saturn is high in the sky in the south-to-southwestern region of the heavens and is visible all night. Look for the constellations Libra and Virgo; Saturn will be between them. On July 15 and 16 the moon will appear very close to Saturn in the sky.

One way to find Saturn is to first locate the Big Dipper. Follow the stars that make up the “handle” to its end, until you locate Spica. Then look above and to the left of Spica to find Saturn.

If you have the opportunity to look through one at an observatory or skywatching event, take advantage of it. You will be able to see Saturn’s rings and some of its moons, including Titan.

Saturn will remain visible in the evening sky until late September or early October.

Jupiter and Mars can be seen in the early morning sky, after dawn, now that both planets are beyond at least some of the sun’s dawn glare. If you are in the United States, look for the solar system’s largest planet to rise about an hour before the sun does.

Mars is obscured by Jupiter to some extent because Jupiter reflects substantially more light from the sun. However, you can see the Red Planet above Jupiter if you look through binoculars until July 22. After that date Jupiter will be the higher of the two planets. Jupiter and Mars will appear in the same binocular field of vision.

The best opportunity to see Jupiter and Mars will occur on July 22. That is the day on which the two planets will appear to be aligned in the heavens. Of course, that is an optical illusion. Jupiter and Mars are separated by about 3.7 astronomical units, or 555 million kilometers!

When you go out to look at Jupiter and Mars, don’t forget your telescope. With it you should be able to see at least some of the four largest moons of Jupiter – Callisto, Europa, Ganymede, and Io.

Mercury will be apparent in the sky toward the end of the month during the early morning. To find it, first locate Jupiter and Mars. Remember: At the end of the month Jupiter will appear above Mars in your field of vision when you look to the eastern sky. If you look below Mars, and just a bit to the left, you should be able to see Mercury a little bit above the horizon.

You don’t have much time to see Mercury. Because it is the planet closest to the sun, it does not rise far above the horizon and it appears in the pre-dawn sky for only a short part of the year. This year you can say goodbye to the opportunity to see it by about the end of the second week of August.


This image of Saturn, obtained by the Voyager 2 spacecraft on July 21, 1981, shows cloud patterns in the planet’s northern hemisphere and the moons Rhea and Dione (blue dots to the south and southeast of Saturn). Image courtesy NASA/Jet Propulsion Laboratory.

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Mann turns spotlight on climate change denier critics

Professor Michael E. Mann, one of the nation’s leading climatologists, has been on the receiving end of intense attacks from climate change deniers, but he’s not taking the abuse lying down.

Phil Plait, the eloquent Bad Astronomy blog author, has posted a video of Mann’s presentation last month at the Chapman Conference, a gathering of scientists sponsored by the American Geophysical Union.

It’s worth a look, and while you’re over at Bad Astronomy check out Dr. Plait’s other excellent work.

Mann, the director of The Pennsylvania State University’s Earth System Science Center, was the lead author of an acclaimed 1999 paper that documented a trend of increased temperatures on Earth during the past 1,000 years.


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Happy Aphelion Day (ok, a little late)

With temperatures blazing hot in many areas of the northern hemisphere, it’s tempting to conclude that our planet is very close to the sun. Don’t be fooled!

Friday was the day on which Earth was as far away from Sol as it will ever be this year. That day is called the planet’s aphelion.

The planet’s aphelion occurs in early July every year. It does not happen on the same day each year.

The difference between the amount of solar energy Earth receives at aphelion and the amount it receives at perihelion – the point in its orbit where the planet is closest to the sun – is about 3.3 percent. Earth’s seasons cause a larger variability in the amount of solar energy received on the planet’s surface.

According to the U.S. Naval Observatory, perihelion will next occur on Jan. 4, 2014, while next year’s aphelion will happen on July 4.

aphelion and perihelion - courtesy NASA

Graphic courtesy NASA.




Newly-discovered Plutonian moons get names

Two newly-discovered moons of Pluto now have names.

The International Astronomical Union announced Tuesday that the fourth and fifth satellites of the solar system’s former ninth planet will be known as Kerberos and Styx.

Like moons of most of Earth’s other planetary neighbors, the names relate to the gods of Greek and Roman mythology.

Kerberos is the name of the dog that guards the underworld in the ancient Greek tales, while Styx is the name of the river that separated Earth and the underworld in those tales.

Both moons are recent discoveries.

“They were both discovered in images from the Hubble Space Telescope,” Mark Showalter, an astronomer associated with the Carl Sagan Center for Study of Life in the Universe at California’s SETI Institute and the leader of the research team that discovered them, said. “P4, which is now Kerberos, was found in 2011, late June or July, and P5 was found about this time in 2012. The discovery of P4 was actually in a short Hubble program to search for dust rings around Pluto. We were doing that by taking longer exposures of Pluto than anyone had attempted before.”

Researchers subsequently decided to look for more evidence of additional satellites of Pluto.

The two moons are very small, on the order of about 100 times smaller than Charon, Pluto’s largest satellite.

“They’re just dots in the sky,” Showalter explained. “The estimates we have are on the order of 10-15 miles in diameter. Three billion miles away, and that’s how big they are. Just to illustrate, P5 is about 100,000 times fainter than Pluto itself. They’re separated on the sky by, basically, a hair’s breadth.”

Charon has a diameter of about 1,200 kilometers.

Kerberos and Styx almost certainly move in synchronous rotation with Pluto, just as Earth’s moon does in relation to our planet.

“Every satellite in the solar system, except Saturn’s moon Hyperion, has been shown to be tidally locked,” Showalter said.

The Hubble Space Telescope was used to find Pluto’s two other known satellites, Nix and Hydra, in 2005. Those moons are named, respectively, for the Greek goddess of darkness and night and the nine-headed serpent that fought Hercules in the ancient myths.

The system of naming moons for characters of Greek and Roman mythology is commonly employed by astronomers in naming the moons of the solar system’s planets.

“Moons of Neptune are named for creatures associated with the oceans in Greek and Roman mythology because Neptune was the god of the ocean,” Showalter said.

Similarly, eight moons of Saturn are named for titans of Greek mythology, while many of Jupiter’s moons – notably excluding Callisto, Europa, Ganymede, and Io – are named for lovers and descendants of Zeus. Mars’ two moons are named for children of Ares, the Greek god of war.

The moons of Uranus are named for characters from English literature, particularly Shakespeare’s plays.

Kerberos and Styx may not be the last moons of Pluto to be discovered. The New Horizons spacecraft is scheduled to arrive in the vicinity of Pluto in 2015, allowing scientists a close-up look at the dwarf planet and its satellites.

“I would be frankly surprised if we don’t find a P6 and a P7 and a P8,” Showalter said. “Whatever is going on in the Pluto system that created this family of moons probably didn’t stop at five.”

He explained that it’s not likely the IAU will have any problem finding names for any newly-discovered Plutonian moons that fit the existing theme.

“I can assure you that is not a concern,” Showalter said. “We had 30,000 write-in candidates put in. There’s a long list. I still have that list. I’d like to think we’ll be returning to that list come 2015 when we find other rocks out there.”Image

Graphic courtesy Wikimedia

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