Pluto Archives

July 11, 2015December 23, 2015 by Ken Kremer

Last, Best Look at Pluto’s Far Side and Four Perplexing Spots: 2 Days Out from Flyby

New Horizons’ last look at Pluto’s Charon-facing hemisphere reveals the highest resolution view of four intriguing darks spots for decades to come. This image, taken early the morning of July 11, 2015, shows newly-resolved linear features above the equatorial region that intersect, suggestive of polygonal shapes. This image was captured when the spacecraft was 2.5 million miles (4 million kilometers) from Pluto. Credit: NASA/JHUAPL/SWRI
Story updated[/caption]

Today (July 11) we got our last, best and clearest look at a quartet of perplexing dark spots on Pluto’s far side from NASA’s New Horizons spacecraft – now just two days and two million miles (4 million km) out from history’s first ever up close flyby of the Pluto system on Tuesday, July 14.

The four puzzling spots (see above) are located on the hemisphere of Pluto which always faces its largest moon, Charon, and have captivated the scientists and public alike. Pluto and Charon are gravitationally locked with an orbital period of 6.4 days.

Over only the past few days, we are finally witnessing an amazing assortment of geological wonders emerge into focus from these never before seen worlds – as promised by the New Horizons team over a decade ago.

Be sure to take a good hard look at the image, because these spots and Pluto’s Charon-facing hemisphere will not be visible to New Horizons cameras and spectrometers during the historic July 14 encounter as the spacecraft whizzes by the binary worlds at speeds of some 30,800 miles per hour (more than 48,600 kilometers per hour) for their first up close reconnaissance.

And it’s likely to be many decades before the next visitor from Earth arrives at the frigid worlds at the far flung reaches of our solar system for a longer look, hopefully from orbit.

“The [July 11] image is the last, best look that anyone will have of Pluto’s far side for decades to come,” said New Horizons principal investigator Alan Stern of the Southwest Research Institute, Boulder, Colorado, in a statement.

The image of the mysterious spots was taken earlier today (July 11) by New Horizons Long Range Reconnaissance Imager (LORRI) at a distance of 2.5 million miles (4 million kilometers) from Pluto, and just released by NASA. The image resolution is 10 miles per pixel. One week ago it was only 40 miles per pixel.

They were first seen only in very recent LORRI images as Pluto’s disk finally was resolved and are located in a Missouri sized area about 300 miles (480 kilometers) across and above the equatorial region.

But until today they were still rather fuzzy – see image below from July 3! What a difference a few million miles (km) makes!

Latest color image of Pluto taken on July 3, 2015. Best yet image of Pluto was taken by the LORRI imager on NASA’s New Horizons spacecraft on July 3, 2015 at a distance of 7.8 million mi (12.5 million km), just prior to the July 4 anomaly that sent New Horizons into safe mode. Color data taken from the Ralph instrument gathered earlier in the mission. Credit: NASA/JHUAPL/SWRI

“The Pluto system is totally unknown territory,” said Dr. John Spencer, New Horizons co-investigator at today’s (July 11) daily live briefing from NASA and the New Horizons team.

“Pluto is like nowhere we’ve even been before. It is unlike anything we’ve visited before.”

Now, with the $700 million NASA planetary probe millions of miles closer to the double planet, the picture resolution has increased dramatically and the team can at least speculate.

Researchers say the quartet of “equally spaced” dark splotches are “suggestive of polygonal shapes” and the “boundaries between the dark and bright terrains are irregular and sharply defined.”

“It’s weird that they’re spaced so regularly,” says New Horizons program scientist Curt Niebur at NASA Headquarters in Washington.

However their nature remains “intriguing” and truly “unknown.”

“We can’t tell whether they’re plateaus or plains, or whether they’re brightness variations on a completely smooth surface,” added Jeff Moore of NASA’s Ames Research Center, Mountain View, California.

“It’s amazing what we are seeing now in the images, showing us things we’ve never seen before,” said Spencer.

“Every day we see things we never knew before. We see these crazy black and white patterns. And we have no idea what these mean.”

Answering these questions and more is what the encounter is all about.

Pluto is just chock full of mysteries, with new ones emerging every day as New Horizons at last homes in on its quarry, and the planet grows from a spot to an enlarging disk with never before seen surface features, three billion miles from Earth after an interplanetary journey of some nine and a half years.

“We see circular things and wonder are those craters? Or are they something else,” Spencer elaborated.

“We saw circular features on Neptune’s moon Triton that are not craters. So we should know in a few days . But right now we are just having an awful lot of fun just speculating. It’s just amazing.”

Until a few days ago, we didn’t know that “the other Red Planet” had a big bright heart and a dark ‘whale-shaped’ feature – see my earlier articles; here and here.

Pluto’s “Heart” is seen in this new image from New Horizons’ Long Range Reconnaissance Imager (LORRI) received on July 8, 2015 after normal science operations resumed following the scary July 4 safe mode anomaly that briefing shut down all science operations. The LORRI image has been combined with lower-resolution color information from the Ralph instrument. Credits: NASA-JHUAPL-SWRI

“When we combine images like this of the far side with composition and color data the spacecraft has already acquired but not yet sent to Earth, we expect to be able to read the history of this face of Pluto,” Moore explained.

New Horizons will swoop to within about 12,500 kilometers (nearly 7,750 miles) of Pluto’s surface and about 17,900 miles (28,800 kilometers) from Charon during closest approach at approximately 7:49 a.m. EDT (11:49 UTC) on July 14.

The probe was launched back on Jan. 19, 2006 on a United Launch Alliance Atlas V rocket on a 9 year voyage of over 3.6 billion miles (5.7 billion km).

Pluto is the last of the nine classical planets to be explored up close and completes the initial the initial reconnaissance of the solar system nearly six decades after the dawn of the space age. It represents a whole new class of objects.

“Pluto is a member of a whole new family of objects,” said Jim Green, director of Planetary Science, NASA Headquarters, Washington, in today’s live Pluto update.

“We call that the Kuiper Belt. And it is the outer solar system.”

New Horizons is equipped with a suite of seven science instruments gathering data during the approach and encounter phases with the Pluto system.

Graphic shows data gathered by New Horizons particle and plasma science instruments from 2 million miles out on July 11, 2015. Credit: NASA/JHUAPL/SWRI

The New Frontiers spacecraft was built by a team led by Stern and included researchers from SwRI and the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland. APL also operates the New Horizons spacecraft and manages the mission.

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer

Tantalizing signs of geology on Pluto are revealed in this image from New Horizons taken on July 9, 2015 from 3.3 million miles (5.4 million km) away. This annotated version shows the large dark feature nicknamed "the whale" that straddles Pluto's equator, a swirly band and a curious polygonal outline. At lower is a reference globe showing Pluto’s orientation in the image, with the equator and central meridian in bold. Credit: NASA-JHUAPL-SWRI — Tantalizing signs of geology on Pluto are revealed in this image from New Horizons taken on July 9, 2015 from 3.3 million miles (5.4 million km) away. This annotated version shows the large dark feature nicknamed “the whale” that straddles Pluto’s equator, a swirly band and a curious polygonal outline. At lower is a reference globe showing Pluto’s orientation in the image, with the equator and central meridian in bold. Credit: NASA-JHUAPL-SWRI

July 10, 2015December 23, 2015 by Bob King

Scientists Captivated By Pluto’s Emerging Geological Wonders

Bit by the Pluto bug? Day by day, new images appear showing an ever clearer view of a world we inexplicably love. Call it a dwarf planet. Call it a planet. It’s the unknown, and we can’t help but be drawn there.

Pluto made history when it was discovered in 1930. In 2015, it’s doing it all over again. Check out the new geology peeping into view.I’m reminded of the early explorers who shoved off in wooden ships in search of land across the water. After a long and often perilous journey, the mists would finally clear and the dark outline of land take form in the distance. It’s been 9 1/2 years since our collective Pluto voyage began. Yeah, we’re almost there.

Science team members react to the latest image of Pluto at the Johns Hopkins University Applied Physics Lab on July 10, 2015. Left to right: Cathy Olkin, Jason Cook, Alan Stern, Will Grundy, Casey Lisse, and Carly Howett. Credit: Michael Soluri — Science team members react to the latest image of Pluto at the Johns Hopkins University Applied Physics Lab on July 10, 2015. Left to right: Cathy Olkin, Jason Cook, Alan Stern, Will Grundy, Casey Lisse, and Carly Howett.
Credit: Michael Soluri

Today’s image release clearly shows a world growing more geologically diverse by the day.

“We’re close enough now that we’re just starting to see Pluto’s geology,” said New Horizons program scientist Curt Niebur, on NASA’s website. Niebur, who’s keenly interested in the gray area just above the whale’s “tail” feature, called it a “unique transition region with a lot of dynamic processes interacting, which makes it of particular scientific interest.”

The non-annotated version of the top photo. The 'whale' lies near the dwarf planet's equator. Pluto's axis is tilted 123° to its orbital plane. Credit: NASA — The non-annotated version of the top photo. The ‘whale’ lies near the dwarf planet’s equator. Pluto’s axis is tilted 123° to its orbital plane. Credit: NASA-JHUAPL-SWRI

Not only that, but the new photo shows an approximately 1,000-mile-long band of swirly terrain crossing the planet from east to northeast, a large, polygonal (roughly hexagonal) feature and new textures within the ‘whale’.

Neptune's largest moon Triton photographed on August 25, 1989 by Voyager 2. Credit: NASA — Neptune’s largest moon Triton photographed on August 25, 1989 by Voyager 2. Triton has a surface of mostly frozen nitrogen, a water ice-rich crust, an icy mantle and rock-metal core. Credit: NASA

Even to a layperson’s eye, Pluto’s terrain appears very different from that of Ceres or Vesta. In trying to make sense of what we see, Neptune’s moon Triton may be our best Plutonian analog with its frosts, weird cantaloupe terrain and an assortment of dark patches, some produced by icy volcanism.

New Horizons was about 3.7 million miles (6 million kilometers) from Pluto and Charon when it snapped this portrait late on July 8, 2015. Credits: NASA-JHUAPL-SWRI — New Horizons was about 3.7 million miles (6 million kilometers) from Pluto and Charon when it snapped this portrait late on July 8, 2015.
Credits: NASA-JHUAPL-SWRI

Other recent photos include this pretty view of Charon and Triton snapped late on July 8. NASA describes them eloquently as “two icy worlds, spinning around their common center of gravity like a pair of figure skaters clasping hands.” Charon and all of Pluto’s known moons formed from debris released when another planet struck Pluto long ago. New Horizons principal investigator Alan Stern attributes its bland color to its composition — mostly water ice. Pluto in contrast has a mantle of water ice, but it’s coated with methane, nitrogen and carbon dioxide ices and possibly organic compounds, too.

Color photos of Pluto and Charon side by side. The arcs along Pluto's right limb are artifacts but not the white border along the bottom. Could it be frost? Credit: — Color photos of Pluto and Charon side by side. The arcs along Pluto’s right limb are artifacts but not the white border along the bottom. Could it be frost? Credit: NASA-JHUAPL-SWRI

Hold on tight – there’s LOTS more to come!

July 8, 2015December 23, 2015 by Ken Kremer

Pluto’s ‘Heart’ Revealed as New Horizons Probe Starts Flyby Campaign: 5 Days Out

The Huge Heart of Pluto
Pluto’s “Heart” is seen in this new image from New Horizons’ Long Range Reconnaissance Imager (LORRI) received on July 8, 2015 after normal science operations resumed following the scary July 4 safe mode anomaly that briefing shut down all science operations. It shows ‘the heart and the whale’ along Pluto’s equator. The LORRI image has been combined with lower-resolution color information from the Ralph instrument. Credits: NASA-JHUAPL-SWRI
Story updated[/caption]

Emotions are rising exponentially with the rousing revelation that Pluto has a huge ‘Heart’ as revealed in stunning new imagery received just today (July 8) from NASA’s New Horizons spacecraft – which has also officially started its intensive flyby campaign merely 5 days out from humanity’s history making first encounter with the last unexplored planet in our Solar System on Tuesday, July 14.

Notably, today’s image showing Pluto’s ‘heart-shaped’ surface feature proves that New Horizons is now fully back in business following the nail-biting July 4 weekend anomaly that unexpectedly sent the probe into a protective status known as ‘safe mode’ and simultaneously sent mission engineers and scientists scurrying to their computer screens to resolve the scary issues and recover the probe back to full operation – just in the nick of time.

The intriguing ‘heart’ is the brightest area on Pluto and “may be a region where relatively fresh deposits of frost—perhaps including frozen methane, nitrogen and/or carbon monoxide—form a bright coating,” say mission scientists.

While in ‘safe mode’ all science operations were temporarily halted for nearly three days as the spacecraft inexorably zooms towards mysterious Pluto and its quintet of moons for our first up close reconnaissance of the frigid world and the Kuiper Belt.

Read my earlier story from July 6 here detailing how the science team and NASA resolved the July 4 anomaly and restored New Horizons to normal operations with little time to spare for its one time only flyby of the other ‘Red Planet’.

The close encounter sequence last for 9 days and it will take 16 months to relay back the vast quantity of data to be collected.

The view of Pluto’s ‘Heart’ was taken by the Long Range Reconnaissance Imager (LORRI) when the spacecraft was just under 5 million miles (8 million kilometers) from Pluto, and is the first to be received back on Earth since the anxiety rush caused by the July 4 anomaly.

The heart covers nearly half of Pluto’s now well resolved disk.

Right beside the large heart-shaped bright area, which measures some 1,200 miles (2,000 kilometers) across, is another enigmatic and elongated equatorial surface on the left side informally dubbed ‘the whale.’

Mission scientists say ‘the whale’ is one of the darkest regions visible to New Horizons and it measures some 1,860 miles (3,000 kilometers) in diameter, making it about 50% wider that the ‘heart.’

Above ‘the whale and the heart’ lies Pluto’s polar region that images show is intermediate in brightness.

NASA also released another perspective view of ‘the whale and the heart’ as seen below.

‘The whale and the heart of Pluto.’ This map of Pluto, made from images taken by the LORRI instrument aboard New Horizons, shows a wide array of bright and dark markings of varying sizes and shapes. Perhaps most intriguing is the fact that all of the darkest material on the surface lies along Pluto’s equator. The color version was created from lower-resolution color data from the spacecraft’s Ralph instrument. Credits: NASA-JHUAPL-SWRI — ‘The whale and the heart of Pluto.’
This map of Pluto, made from images taken by the LORRI instrument aboard New Horizons, shows a wide array of bright and dark markings of varying sizes and shapes. Perhaps most intriguing is the fact that all of the darkest material on the surface lies along Pluto’s equator. The color version was created from lower-resolution color data from the spacecraft’s Ralph instrument. Credits: NASA-JHUAPL-SWRI

Be sure to keep this entire area in mind – as if your appetites haven’t been whetted enough already – because “this view is centered roughly on the area that will be seen close-up during New Horizons’ July 14 closest approach,” says NASA.

“The next time we see this part of Pluto at closest approach, a portion of this region will be imaged at about 500 times better resolution than we see today,” said Jeff Moore, Geology, Geophysics and Imaging Team Leader of NASA’s Ames Research Center, in a statement. “It will be incredible!”

With barely 5 days to go until the once-in-a-lifetime opportunity for a fast flyby encounter of the ever intriguing binary planet traveling at the far flung reaches of the solar system, last minute glitches are the last thing anyone needs.

Why? Because there are no second chances as New Horizons barrels towards the Pluto system at approximately 30,000 miles per hour (over 48,000 kilometers per hour), which forms a binary planet with its largest known moon – Charon.

“The New Horizons spacecraft and science payload are now operating flawlessly,” Alan Stern, New Horizons principal investigator, Southwest Research Institute, Boulder, Colorado, announced at the July 6 post anomaly media briefing.

The nature of Pluto’s features that may appear to resemble craters or volcanoes is not yet known.

“We should be very cautious in interpreting these features,” Stern told Universe Today.

TThe probe was launched back on Jan. 19, 2006 on a United Launch Alliance Atlas V rocket on a 9 year voyage of over 3.6 billion miles (5.7 billion km).

“We are on our way to Pluto!” exclaimed Jim Green, director of Planetary Science, NASA Headquarters, Washington, at the July 6 news media briefing. “It’s really a historic time, fraught with many decisions and challenges on the way to the July 14 Pluto system encounter.”

“With Pluto in our sights, we’re going for the gold.”

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer

This trio of images are the most recent high-resolution views of Pluto sent by NASA’s New Horizons spacecraft, including one showing the four mysterious dark spots on Pluto that have captured the imagination of the world. The Long Range Reconnaissance Imager (LORRI) obtained these three images between July 1 and 3 of 2015, prior to the July 4 anomaly that sent New Horizons into safe mode. Credit: NASA/JHUAPL/SWRI

July 6, 2015December 23, 2015 by Ken Kremer

New Horizons Exits Safe Mode, Operating Flawlessly for Upcoming Pluto Encounter

Latest color image of Pluto taken on July 3, 2015 shows 4 mysterious dark spots.
Best yet image of Pluto was taken by the LORRI imager on NASA’s New Horizons spacecraft on July 3, 2015 at a distance of 7.8 million mi (12.5 million km), just prior to the July 4 anomaly that sent New Horizons into safe mode. Color data taken from the Ralph instrument gathered earlier in the mission. Credit: NASA/JHUAPL/SWRI
Story updated[/caption]

Despite some hair-raising and unplanned 4th of July fireworks of sorts in deep space which caused NASA’s Pluto bound New Horizons spacecraft to enter “safe mode” due to a computer glitch and temporarily halt all science operations over the weekend, the spacecraft is now fully back on track, “healthy” and working “flawlessly” and set to resume all planned research investigations on Tuesday, July 7, NASA and top mission managers announced at a media briefing held this afternoon, Monday, July 6.

It’s now just exactly one week before the once-in-a-lifetime opportunity for a fast flyby encounter of the ever intriguing binary planet, at the far flung reaches of the solar system. And the great news could not come soon enough given the proximity of the flyby.

“The spacecraft is in excellent health and back in operation. New Horizons is barreling towards the Pluto system,” stated Jim Green, director of Planetary Science, NASA Headquarters, Washington, at the start of today’s news media briefing.

The $700 million mission remains on track to conduct the complex close flyby science sequence in its entirety, as planned over the next week, including the July 14 flyby of Pluto, despite the scary safe mode episode.

NASA unexpectedly lost contact with the New Horizons spacecraft on Saturday, July 4, at about 1:30 p.m. EDT after it suffered a memory related software anomaly and executed a protective operation known as “safe mode.” An anomaly investigation team was formed immediately.

“It’s really a historic time, but also fraught with many decisions and challenges on the way to the July 14 Pluto system encounter,” Green said.

The mission team quickly worked to reestablish contact with the piano shaped spacecraft about 90 minutes after the signal was lost.

“On Saturday we lost contact with the spacecraft. The New Horizons team immediately went into action. Within 90 minutes the signal was reacquired by the team, with the spacecraft in safe mode. They soon found the root cause and corrective actions were immediately taken to get the spacecraft back in business.”

The team worked tirelessly and diligently day and night over the holiday weekend to recover New Horizons back to full operation quickly and in time for the flyby encounter of Pluto on July 14, set for approximately 7:49 a.m. EDT (11:49 UTC) on July 14, said Glen Fountain, New Horizons project manager, Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland.

There are no second chances.

The software glitch occurred a day after new operating software was uploaded to New Horizons last Friday.

The spacecraft was trying to do two things at once on Saturday, compressing science data and writing command sequences while using up too much flash memory, explained Fountain.

“The computer was trying to do these two things at the same time, and the two were more than the processor could handle,” Fountain said.

“So the processor said ‘I’m overloaded.’ Then the spacecraft did exactly what it was supposed to do. It then switched to the backup computer and went into safe mode. At that point, we lost the downlink from the primary computer. We realized quickly what happened and put a recovery plan in place and recovered.”

Artist view of New Horizons passing Pluto and three of its moons. The ship is about the size of a grand piano and kept warm in the cold of the outer Solar System by heat release from the radioactive decay of plutonium within the probe's RTGs (Radioisotope Thermoelectric Generator). Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute — Artist view of New Horizons passing Pluto and three of its moons. The ship is about the size of a grand piano and kept warm in the cold of the outer Solar System by heat release from the radioactive decay of plutonium within the probe’s RTGs (Radioisotope Thermoelectric Generator). Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

At this moment New Horizons is about 3 billion miles (4.9 billion km) from Earth and less than 6 million miles (9 million km) away from unmasking the secrets of tantalizing Pluto, Charon, its largest moon with which it forms a double planet system, and its four tiny and recently discovered moons. Charon is half the size of Pluto.

The round trip time for signals traveling at the speed of light is 8.5 hours. So it’s a very long time before commands from Earth can reach the spacecraft and for the team to determine their outcome. So the probe has to be able to operate on its own without direction from Earth during the intense and brief flyby period.

Pluto is the most distant and last unexplored planet in our Solar System, and therefore presents enormous complexities to those bold enough to dare the mightiest things.

“We expect a nominal flyby of Pluto from every indication now,” said Alan Stern, New Horizons principal investigator, Southwest Research Institute, Boulder, Colorado, announced at the media briefing.

“This object is unlike any other that we have observed,” Stern said. “Both Pluto and Charon are already surprising us.”

Less than 1 percent of the planned data was lost in the three days that the science instruments were shut off.

“It’s more important to focus on the later science during the flyby,” Stern elaborated.

“There is zero impact to the primary Group 1 highest-priority science objectives. And a minor impact to Group 2 and Group 3 objectives,” Stern elaborated.

“This is a speed bump in terms of the total return that we expect from this flyby.”

“I’m pleased that our mission team quickly identified the problem and assured the health of the spacecraft,” noted Green. “Now, with Pluto in our sights, we’re on the verge of returning to normal operations and going for the gold.”

New Horizons trajectory map to Pluto. Credit: NASA/JHUAPL/SWRI

The team said this type of software update will not be repeated and a similar type safe mode event should not recur.

Fountain said that during the encounter period, the probe can switch itself to exit safe mode event within about 7 minutes, depending on the situation, and minimize any science data losses.

New Horizons will swoop to within about 12,500 kilometers (nearly 7,800 miles) of Pluto’s surface.

It will zoom past Pluto at speeds of some 30,000 miles per hour (more than 48,000 kilometers per hour).

Today the team also released the best yet images of Pluto that were taken by the Long Range Reconnaissance Imager (LORRI). The trio of images were between July 1 and 3 of 2015, prior to the July 4 anomaly that sent New Horizons into safe mode.

The images show varying and enigmatic surface features on the different hemispheres of Pluto.

They also show the four mysterious dark spots on Pluto that have captured the imagination of the scientists and the world.

Their nature remains unknown at this time.

The probe was launched back in 2006 on a United Launch Alliance Atlas V rocket.

“We are on our way to Pluto!” Green exclaimed.

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer

Animation of Pluto rotating from photos taken by New Horizons two weeks before the flyby. Credit:

July 6, 2015December 23, 2015 by David Dickinson

Catching Earth at Aphelion

Do you feel a little… distant today? The day after the 4^th of July weekend brings with it the promise of barbecue leftovers and discount fireworks. It also sees our fair planet at aphelion, or its farthest point from the Sun. In 2015, aphelion (or apoapsis) occurs at 19:40 Universal Time (UT)/3:40 PM EDT today, as we sit 1.01668 astronomical units (AU) from the Sun. This translates to 152.1 million kilometres, or 94.5 million miles. We’re actually 3.3% closer to the Sun in early January than we are today. This also the latest aphelion has occurred on the calendar year since 2007, and it won’t fall on July 6^th again until 2018. The insertion of an extra day every leap year causes the date for Earth aphelion to slowly vary between July 3^rd and July 6^th in the current epoch.

Aphelion sees the Earth 4.8 million kilometers farther from the Sun than perihelion in early January. The eccentricity of our orbit—that is, how much our planet’s orbit varies from circular to elliptical—currently sits at 0.017 or 1.7%.

It is ironic that we’re actually farther from the Sun in the middle of northern hemisphere summer. It sure doesn’t seem like it on a sweltering Florida summer day, right? That’s because the 23.44 degree tilt of the Earth’s rotational axis is by far the biggest driver of the seasons. But our variation in distance from the Sun does play a factor in long term climate as well. We move a bit slower farther from the Sun, assuring northern hemisphere summers are currently a bit longer (by about 4 days) than winters. The variation in solar insolation between aphelion and perihelion currently favors hot dry summers in the southern hemisphere.

But these factors are also slowly changing as well.

The eccentricity of our orbit varies from between 0.000055 and 0.0679 over a span of a ‘beat period’ of 100,000 years. Our current trend sees eccentricity slowly decreasing.

The tilt of our rotational axis varies between 22.1 and 24.5 degrees over 41,000 years. This value is also currently on a decreasing trend towards its shallow minimum around 11,800 AD.

And finally, the precession of the Earth’s axis and apsidal precession combine to slowly move the date of aphelion and perihelion one time around our calendar once every 21,000 years.

These combine to form what are known as Milankovitch Cycles of long-term climate variation, which were first expressed by astronomer Milutin Milankovic in 1924. Anthropogenic climate change is a newcomer on the geologic scene, as human civilization does its very best to add a signal of its very own to the mix.

We also just passed the mid-point ‘pivot of the year’ on July 2nd. More than half of 2015 is now behind us.

Want to observe the aphelion and perihelion of the Earth for yourself? If you have a filtered rig set to photograph the Sun, try this: take an image of the Sun today, and take another on perihelion next year on January 2nd. Be sure to use the same settings, so that the only variation is the angular size of the Sun itself. The disk of the Sun varies from 33’ to 31’ across. This is tiny but discernible. Such variations in size between the Sun and the Moon can also mean the difference between a total solar and annular eclipse.

Should we term the aphelion Sun a #MiniSol? Because you can never have too many internet memes, right?

And did you know: the rotational axis of the Sun is inclined slightly versus the plane of the ecliptic to the tune of 7.25 degrees as well. In 2015, the Sun’s north pole was tipped our way on March 7^th, and we’ll be looking at the south pole of our Sun on September 9^th.

And of course, seasons on other planets are much more extreme. We’re just getting our first good looks at Pluto courtesy of New Horizons as it heads towards its historic flyby on July 14^th. Pluto reached perihelion in 1989, and is headed towards aphelion 49 AU from the Sun on the far off date in 2114 AD. Sitting on Pluto, the Sun would shine at -19th magnitude—about the equivalent of the twilight period known as the ‘Blue Hour’ here on Earth—and the Sun would appear a scant one arc minute across, just large enough to show a very tiny disk.

All thoughts to consider as we start the long swing inward towards perihelion next January.

Happy aphelion!

July 5, 2015December 23, 2015 by Bob King

NASA Loses Contact with New Horizons; Probe Now in Safe Mode

NASA briefly lost touch with the New Horizons spacecraft yesterday. Communications have been reestablished but science data will be delayed. Credit: NASA

For a nail-biting hour and 20 minutes, NASA lost contact yesterday afternoon July 4 with the New Horizons spacecraft just 9 days before its encounter with Pluto. Communication has since been reestablished and the spacecraft is healthy.

(UPDATE July 6: Great news! The mission will return to normal science operations July 7 – more details below.)

At 1:54 p.m. EDT, communications suddenly stopped and weren’t reestablished until 3:15 p.m. through NASA’s Deep Space Network. During the time it was out of contact with mission control, the spacecraft’s autonomous autopilot recognized the problem and did what it was programmed to do, switching from the main to the backup computer, according to NASA officials. The autopilot then commanded the backup computer to put New Horizons in “safe mode” — where all non-essential functions are shut down — and reinitiate communications with Earth.

Success! We’re now back in touch with the spacecraft and engineers are monitoring telemetry to figure out what went wrong. New Horizons is presently almost 3 billion miles (4.9 billion km) from Earth. Due to the 8.8 hour, round trip communication delay, full recovery is expected to take from one to several days. During that time New Horizons will be unable to collect science data.

If there’s any upside to this, it’s that it happened now instead of 9 days from now. On July 14 at 7:49:57 a.m. EDT the spacecraft will pass closest to Pluto.

Check back for updates. In the meantime, you can watch a live connection between New Horizons and the Deep Space Network. The probe is labeled NHPC and the dish 63 (first entry).

UPDATE: July 6. NASA announced earlier this morning that has concluded the glitch that caused the New Horizons spacecraft to go into safe mode was not due to a software or hardware fault.

“The underlying cause of the incident was a hard-to-detect timing flaw in the spacecraft command sequence that occurred during an operation to prepare for the close flyby. No similar operations are planned for the remainder of the Pluto encounter,” according to a NASA release.

No primary science will be lost and secondary goals were only slightly compromised. Mission control expects science operations to resume on July 7 and to conduct the entire close flyby sequence as planned.

“In terms of science, it won’t change an A-plus even into an A,” said New Horizons Principal Investigator Alan Stern.

Whew! What a sense of relief. Onward!

July 4, 2015December 23, 2015 by Bob King

Red-faced Pluto Full of Surprises

New Horizons scientists combined the latest black and white map of Pluto’s surface features (left) with a map of the planet’s colors (right) to produce a detailed color portrait of the planet’s northern hemisphere (center). Credits: NASA/JHUAPL/SWRI

Hey, Mars, you’ve got company. Looks like there’s a second “red planet” in the Solar System — Pluto. Color images returned from NASA’s New Horizons spacecraft, now just 10 days from its encounter with the dwarf planet, show a distinctly ruddy surface with patchy markings that strongly resemble Mars’ appearance in a small telescope.

On Mars, iron oxide or rust colors the planet’s soil, while Pluto’s coloration is likely caused by hydrocarbon molecules called tholins that are formed when cosmic rays and solar ultraviolet light interact with methane in Pluto’s atmosphere and on its surface. Airborne tholins fall out of the atmosphere and coat the surface with a reddish gunk.

Scientists at Johns Hopkins University’s Hörst Laboratory have produced complex chemical compounds called tholins, which may give Pluto its reddish hue. Credits: Chao He, Xinting Yu, Sydney Riemer, and Sarah Hörst, Johns Hopkins University — Scientists at Johns Hopkins University’s Hörst Laboratory have produced complex chemical compounds called tholins, which may give Pluto its reddish hue.
Credits: Chao He, Xinting Yu, Sydney Riemer, and Sarah Hörst, Johns Hopkins University

A particular color or wavelength of UV light called Lyman-alpha is most effective at stimulating the chemical reactions that build hydrocarbons at Pluto. Recent measurements with New Horizons’ Alice instrument reveal the diffuse glow of Lyman-alpha light all around the dwarf planet coming from all directions of space, not just the Sun.

Since one of the main sources of Lyman-alpha light besides the Sun are regions of vigorous star formation in young galaxies, Pluto’s cosmetic rouge may originate in events happening millions of light years away.

Triton's pink too! Montage of Neptune's largest moon, Triton (1,683 miles in diameter) and the planet Neptune showing the moon's sublimating south polar cap (bottom) and enigmatic "cantaloupe terrain". Credit: NASA — Triton’s pink too! Montage of Neptune’s largest moon, Triton (1,683 miles in diameter) and the planet Neptune showing the moon’s sublimating south polar cap (bottom) and enigmatic “cantaloupe terrain”. Photo taken by Voyager 2 in 1989. Credit: NASA

“Pluto’s reddish color has been known for decades, but New Horizons is now allowing us to correlate the color of different places on the surface with their geology and soon, with their compositions,” said New Horizons principal investigator Alan Stern of the Southwest Research Institute, Boulder, Colorado.

Tholins have been found on other bodies in the outer Solar System, including Titan and Triton, the largest moons of Saturn and Neptune, respectively, and made in laboratory experiments that simulate the atmospheres of those bodies.

True color photos showing the two hemispheres of Pluto. At right, you can clearly see the four streaks in a row. New Horizons will approach fly by the hemisphere on the left side. — True color photos showing the two hemispheres of Pluto photographed on June 27, 2015. At left, a large, dark red patch is visible. The four streaks in a row are seen at right. New Horizons will fly by the hemisphere in the left image. Credit: NASA/JHUAPL/SWRI

As you study the photos and animation, you’ll notice that Pluto’s largest dark spot is redder than the most of the surface; you also can’ help but wonder what’s going on with those four evenly-spaced dark streaks in the equatorial zone. When I first saw them, my reaction was “no way!” They look so neatly lined up I assumed it was an image artifact, but after seeing the rotating movie, maybe not. It’s more likely that low resolution enhances the appearance of alignment.

Dark streaks on Triton formed by deposits from ice or cryovolcanos. Credit: NASA — Dark streaks on Triton deposited downwind from ice or cryovolcanos. Credit: NASA

But what are they? Located as they are on the Charon-facing side of Pluto, they may be related to long-ago tidal stresses induced by each body on the other as they slowly settled into their current tidally-locked embrace or something as current as seasonal change.

Voyager 2 photographed cyrovolcanos at Triton during its 1989 flyby of the Neptune system. Nitrogen geysers and plumes of gas and ice as high as 5 miles (8 km) were seen erupting from active volcanoes, leaving dark streaks on its icy surface.

Images showing the increase in detail from late June through July 1 as New Horizons homes in on Pluto. Credit: — Images showing the increase in detail from late June through July 1 as New Horizons homes in on Pluto. That possible big crater (seen in bottom middle photo) now looks more like a large, dark patch, BUT we still don’t know for sure what it is. Credit: NASA / JHUAPL / SwRI / Björn Jónsson

It's instructive to compare these images based on observations with the Hubble Space Telescope made well before New Horizons's arrival. They appear to record the large dark spot and possible the multiple streaks. Credit: NASA/ESA — It’s instructive to compare these images, based on observations with the Hubble Space Telescope made well before New Horizons’s arrival, with current photos. They appear to record the large dark spot and possibly the multiple streaks. Credit: NASA/ESA

Seasonal heating from the Sun is the most likely cause for Triton’s eruptions; Pluto’s dark streaks may have a similar origin.

Animation of Pluto and Charon from images taken between June 23 and June 29. Credit: NASA/JHUAPL/SWR

To give you a better picture in your head how big these small bodies are, Pluto and Charon would both fit within the United States with room to spare. Credit: Laboratory for Atmospheric and Space Physics (LASP) — To better picture in your head how big these small bodies really are, Pluto and Charon would both fit within the United States with room to spare. Credit: Laboratory for Atmospheric and Space Physics (LASP)

Today, New Horizons lies just 7.4 million miles (11.9 million km) from its target. Sharpness and detail visible will rapidly improve in just a few days.

“Even at this resolution, Pluto looks like no other world in our Solar System,” said mission scientist Marc Buie of the Southwest Research Institute, Boulder in a recent press release.

Indeed!

June 30, 2015December 23, 2015 by David Dickinson

See Pluto for Yourself Ahead of New Horizons’ Historic Encounter

Are you ready for July? The big ticket space event of the year is coming right up, as NASA’s New Horizons spacecraft is set to make its historic flyby targeting a pass 12,500 kilometres (7,750 miles) from the surface of Pluto at 11:50 UT on July 14^th. Already, Pluto and its moons are growing sharper by the day, as New Horizons closes in on Pluto at over 14 kilometres per second.

And the good news is, this flyby of the distant world occurs just eight days after Pluto reaches opposition for 2015, marking a prime season to track down the distant world with a telescope.

Pluto and its large moon Charon are snapping into focus as we reach the two week out mark. Discovered in 1930 by astronomer Clyde Tombaugh while working at the Lowell observatory in Flagstaff Arizona, these far off worlds are about to become real places in the public imagination. It’s going to be an exciting—if tense—few weeks, as new details and features are seen on these brave new worlds, all calling out for names. Are there undiscovered moons? Does Pluto host a ring system? What is the history of Pluto?

Hunting for Pluto with a backyard telescope is difficult, though not impossible. We suggest an aperture of 10-inches or greater, though the tiny world has been reliably spotted using a 6-inch reflector. Pluto reaches opposition on July 6^th at 10:00 UT/6:00 AM EDT, marking a period when it will rise opposite to the setting Sun and transit highest near local midnight. Pluto spends all of 2015 in the constellation Sagittarius. This presents two difficulties: 1). We’re currently looking at Pluto against the very star-rich backdrop towards the center of the Milky Way Galaxy, and 2). Its southerly declination means that it won’t really ‘clear the weeds’ much for northern hemisphere observers.

But don’t despair. With a good finder chart and patience, you too can cross Pluto off of your life list. In fact, the month of July sees Pluto thread its way between the 27’ wide +4^th magnitude pair Xi Sagittarii, making a great guidepost to spot the 14^th magnitude world.

Don’t own a telescope? You can still wave in the general direction of New Horizons and Pluto on the evening of July 1^st, using the nearby Full Moon as a guide:

Pluto orbits the Sun once every 248 years, and reaches opposition every 367 days. A testament to this slow motion is the fact that Mr. Tombaugh first spied Pluto south of the star Delta Gemini, and it has only moved as far as Sagittarius in the intervening 85 years. Pluto also passed perihelion in 1989, when it was about half a magnitude brighter than it currently is now. Pluto’s distance from the Sun varies from 30 AU to 49 AU, and Pluto will reach aphelion just under a century from now on 2114.

Up for a challenge? Hunting down Pluto’s elusive moon Charon is an ultimate feat of astronomical athletics. Amazingly, this has actually been done before, as reported here in 2008 on Universe Today.

Charon reaches greatest elongation 0.8” from Pluto once every three days. Shining at +16^th magnitude, Charon is a faint catch, though not impossible. We’re already seeing supporting evidence from early New Horizons images that these two worlds stand in stark contrast, with dark Charon covered in relatively low albedo dirty water-ice and while brighter Pluto is coated with reflective methane snow.

Greatest elongation times and dates for Charon through the month of July 2015. Credit: Ed Kotapish

The current forward-looking view from New Horizons of Pluto is amazing to consider. As of July 1^st, the spacecraft is 0.11 AU (17 million kilometres) from Pluto and closing, and the world appears as a +1.7 magnitude object about 30 arc seconds across. The views of Pluto are courtesy of New Horizons’ LORRI (Long Range Reconnaissance Imager), which in many ways is very similar to a familiar backyard 8-inch Schmidt-Cassegrain telescope. It’s interesting to note that the views we’re currently getting very closely resemble amateur views of Mars near opposition, though we suspect that will change radically in about a week.

And it will take months for all of the New Horizons data to make its way back to Earth. The real nail-biter will be the 20 hour period of close rendezvous on July 14^th, a period in which the spacecraft will have to acquire Pluto and Charon, do its swift ballet act, and carry out key observations—all on its own before phoning home. This will very likely be the only mission to Pluto in our lifetimes, as New Horizons will head out to rendezvous with several Kuiper Belt Objects in the 2020 time frame before joining the Voyager I & II and Pioneer 10 & 11 spacecraft in an orbit around the Milky Way Galaxy.

Just think, in less than a few weeks time, science writers will (at last!) have a wealth of Plutonian imagery to choose from courtesy of New Horizons, and not just a few blurry pics and artist’s conceptions that we’ve recycled for decades… let us know of your tales of tribulation and triumph as you attempt to hunt down Pluto this summer!

June 30, 2015December 23, 2015 by Bob King

Is That a Big Crater on Pluto? Pyramidal Mountain Found on Ceres

Pluto with its enigmatic "crater" photographed on June 27. The apparent row of three depressions near the bottom of the globe are most likely artifacts from processing. Credit:

You’re probably as eager as I am for new images of Pluto and Ceres as both New Horizons and Dawn push ever closer to their respective little worlds. Recent photos, of which there are only a few, reveal some wild new features including what appears to a large crater on Pluto.

The latest photo of Pluto (lower left) and its largest moon Charon taken on June 29. A large possible crater-like feature is visible at lower right. Charon shows intriguing dark markings. Pluto's diameter is 1,471 miles (700 miles smaller than Earth's Moon); Charon is 750 miles across. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute — The latest photo of Pluto (lower left) and its largest moon Charon taken on June 29. A large possible crater-like feature is visible at lower right. Charon shows intriguing dark markings. Pluto’s diameter is 1,471 miles (700 miles smaller than Earth’s Moon); Charon is 750 miles across. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

In the end, this apparent large impact might only be a contrast effect or worse, an artifact of over-processing, but there’s no denying its strong resemblance to foreshortened, shadow-filled craters seen on the Moon and other moons. It’s also encouraging that an earlier photo from June 27 shows the same feature. But the “crater” is just so … big! Its size seems disproportionate to the Pluto’s globe and recalls Saturn’s 246-mile-wide moon Mimas with its 81-mile-wide crater Herschel.

Pluto (right) and Charon, with its unusual dark north polar cap or “anti-cap” in a photo taken by New Horizons’ long-range camera on June 19, 2015. Pluto’s 1,471 miles in diameter; Charon’s half that size. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute — Pluto (right) and Charon, showing an unusual dark north polar cap or “anti-cap” in a photo taken by New Horizons’ long-range camera on June 19, 2015. The two were about 20 million miles away at the time. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Astronomers speculate the impact that gouged out Herschel came perilously close to shattering the moon to pieces. If it does turn out to be an crater, Pluto’s surface opposite the impact will likely show many fractures. Not to be outdone, the dwarf planet’s largest moon, Charon, is starting to show a personality of its own with a prominent dark north polar cap.

Since polar caps are normally bright, icy features, some have referred to this one as an “anti-polar cap”. Speaking of ice, the bright rim around Pluto in the photo above may be nitrogen frost condensing out of Pluto’s scant atmosphere as it slowly recedes from the Sun. Think how cold it must have to get for nitrogen to freeze out. How about -346° F (-210° C)! For new images of the Pluto system, be sure to check the New Horizons LORRI gallery page.

Dawn took this photo of an intriguing pyramidal mountain on Ceres on June 14 from an altitude of 2,700 miles. It rises 3 miles above a relatively smooth surface. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA — Dawn took this photo of an intriguing pyramidal mountain (top center) on Ceres on June 14 from an altitude of 2,700 miles. It rises 3 miles above a relatively smooth surface. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Closer to home, new photos of Ceres show a peculiar, pyramid-shaped mountain towering 3 miles (5 km) high from a relatively smooth region between two large craters. Mountains poking from crater floors aren’t unusual. They’re tossed up after the crust later rebounds after a large impact. What makes this one unusual is the lack of an associated crater. Moreover, the mountain’s pale hue could indicate it’s younger than the surrounding landscape. As far as we can tell, it’s the only tall mountain on the face of the dwarf planet.

Another more overhead view of the mountain (right of center) taken by NASA's Dawn probe on June 6. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA — Another more overhead view of the mountain (right of center) taken by NASA’s Dawn probe on June 6. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Cropped version of the photo above. Notice the striations on the mountainside possibly from landslides. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

The Dawn team also photographed that cluster of white spots again, this time with a very shot exposure in to eke out more details. What do you think? If you’re as interested in asteroids as I am, Italian astrophysicist Gianluca Masi, a frequent photo contributor to Universe Today, will host a special live Asteroid Day event today starting at 6 p.m. CDT (23:00 UT). Masi will review near-Earth asteroids, explain discovery techniques and observe several in real time.

The Dawn team greatly underexposed Ceres in order to tease out more details from the white spot cluster in this image made on June 15 from 2,700 miles altitude. I've lightened the limb of Ceres, so you can see the context better. Credit: — The Dawn team greatly underexposed Ceres in order to tease out more details from the white spot cluster in this image made on June 15 from 2,700 miles altitude. I’ve lightened the limb of Ceres to provide context. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Dawn photographed the large crater at left along with an interesting chain of craters and possible fault or collapse features. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute — Dawn photographed the large crater at left along with an interesting chain of craters and possible fault or collapse structures. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

June 23, 2015December 23, 2015 by Nancy Atkinson

“Oh Pluto” Will Tug at Your Heartstrings

I’m as guilty as anyone for anthropomorphizing Pluto — as well as spacecraft like New Horizons, which is currently preparing to fly by the dwarf planet. But since spacecraft are really just extensions of ourselves, perhaps I can be forgiven for my non-scientific projections.

But now I know I’m among friends.

A new song by folk musician Craig Werth called “Oh Pluto” is “inspired by NASA’s New Horizons Mission to Pluto and the quest for knowledge and understanding in the human spirit,” says Werth. The song underscores how we want to “grow our understanding, to learn all that we can.”

A noble goal, indeed.

Look for some familiar faces in the video.

Werth is joined on “Oh Pluto” by other notables Christine Lavin, Emily Bindiger and Grammy-winner, Julie Gold.

New Horizons is also inspiring other works of art, such as poetry by our pal Stu Atkinson who says “Soon we will Know You; soon we will swoon to pin-sharp views.”