Dream Chaser Spacecraft May Be Used For Hubble Repair Mission

The Dream Chaser Space System, built by the Sierra Nevada Corporation, may be used for one more servicing mission to the Hubble Space Telescope. Image: By NASA - http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=66081, Public Domain, https://commons.wikimedia.org/w/index.php?curid=27237176

The final servicing mission to the venerable Hubble Space Telescope (HST) was in 2009. The shuttle Atlantis completed that mission (STS-125,) and several components were repaired and replaced, including the installation of improved batteries. The HST is expected to function until 2030 – 2040. With the retiring of the shuttle program in 2011, it looked like the Hubble mission was destined to play itself out.

But now there’s talk of another servicing mission to the Hubble, to be performed by the Dream Chaser Space System.

A view of the Hubble Space Telescope from inside space shuttle Atlantis on mission STS-125 in 2009, the final repair mission. Credit: NASA

The Hubble was originally deployed by the Space Shuttle Discovery in 1990. It was serviced by crew aboard the shuttles 5 times on 5 different shuttle missions. Unlike the other observatories in NASA’s Great Observatories, the Hubble was designed to be serviced during its lifetime.

Those servicing missions, which took place in 1993, 1997, 1999, 2002, and 2009, were complex missions which required coordination between the Kennedy Space Center, Johnson Space Center, and the Goddard Space Flight Center. Grasping Hubble with the robotic Canadarm and placing it inside the shuttle bay was a methodical process. So was the repair and replacement of components, and the testing of components once Hubble was removed from the cargo bay. Though complicated, these missions were ultimately successful, and the Hubble is still operating.

The robotic Canadarm during STS-72, as Space Shuttle Endeavour mission in 1996. Image: By NASA – https://archive.org/details/STS072-722-041, Public Domain, https://commons.wikimedia.org/w/index.php?curid=29803999

A future servicing mission to the Hubble would be a sort of insurance policy in case there are problems with NASA’s new flagship telescope, the James Webb Space Telescope (JWST.) The JWST is due to be launched in 2018, and its capabilities greatly exceed those of the Hubble. But the James Webb’s destination is LaGrange Point 2 (L2), a stable point in space about 1.5 million km (932,000 miles) from Earth. It will enter a halo orbit around L2, which makes a repair mission difficult. Though deployment problems with the JWST could be corrected by visiting spacecraft, the Telescope itself is not designed to be repaired like the Hubble is.

Since the JWST is risky, both in terms of its position in space and its unproven deployment method, some type of insurance policy may be needed to ensure NASA has a powerful telescope operating in space. But without Space Shuttles to visit the Hubble and extend its life, a different vehicle would have to be tasked with any potential future servicing missions. Enter the Dream Chaser Space System (DCSS).

The Dream Chaser Space System is like a smaller Space Shuttle. It can carry seven people into Low-Earth Orbit (LEO). Like the Shuttles, it then returns to Earth and lands horizontally on an airstrip. The DCSS, however, does not have a cargo bay or a robotic arm. If it were used for a Hubble repair mission, all repairs would likely have to be done during spacewalks. The DCSS is designed as a cargo and crew resupply ship for the International Space System. The much larger shuttles were designed with the Hubble in mind, as well as other tasks, like building and servicing the ISS and recovering satellites from orbit.

The DCSS is built by Sierra Nevada Corporation. It will be launched on an Atlas V rocket, and will return to Earth by gliding, where it can land on any commercial runway. The DCSS has its own reaction control system for manoeuvering in space. Like other commercial space ventures, the development of the DCSS has been partly funded by NASA.

The primary mirror of the James Webb Space Telescope is unfolded once it's in space. If it fails to deploy properly, NASA may need to use the Dream Chaser to keep the Hubble Telescope operating instead. Image: NASA/Chris Gunn
The primary mirror of the James Webb Space Telescope. Image: NASA/Chris Gunn

The James Webb has a complex deployment. It will be launched on an Ariane 5 rocket, where it will be folded up in order to fit. The primary mirror on the JWST is made up of 18 segments which must unfold in three sections for the telescope to function. The telescope’s sun shield, which keeps the JWST cool, must also unfold after being deployed. Earlier in the mission, the Webb’s solar array and antennae need to be deployed.

This video shows the deployment of the JWST. It reminds one of a giant insect going through metamorphosis.

If either the mirror, the sunshield, or any of the other unfolding mechanisms fail, then a costly and problematic mission will have to be planned to correct the deployment. If some other crucial part of the telescope fails, then it probably can’t be repaired. NASA needs everything to go well.

People have been waiting for the JWST for a long time. It’s had kind of a tortured path to get this far. We all have our fingers crossed that the mission succeeds. But if there are problems, it may be up to the Hubble to keep doing what it’s always done: provide the kinds of science and stunning images that excites scientists and the rest of us about the Universe.

What Will the Voyager Spacecraft Encounter Next? Hubble Helps Provide a Roadmap

An artist's concept of Voyager 1's view of the Solar System. Voyager 1 is one of our first interstellar probes, though it's an inadvertent one. It has no particular destination. Credit: NASA, ESA, and J. Zachary and S. Redfield (Wesleyan University); Artist's Illustration Credit: NASA, ESA, and G. Bacon (STScI).

The twin Voyager spacecraft are now making their way through the interstellar medium. Even though they are going where none have gone before, the path ahead it is not completely unknown.

Astronomers are using the Hubble Space Telescope to observe the ‘road’ ahead for these pioneering spacecraft, to ascertain what various materials may lay along the Voyagers’ paths through space.

Combining Hubble data with the information the Voyagers are able to gather and send back to Earth, astronomers said a preliminary analysis reveals “a rich, complex interstellar ecology, containing multiple clouds of hydrogen laced with other elements.”

“This is a great opportunity to compare data from in situ measurements of the space environment by the Voyager spacecraft and telescopic measurements by Hubble,” said Seth Redfield of Wesleyan University, who led the study. “The Voyagers are sampling tiny regions as they plow through space at roughly 38,000 miles per hour. But we have no idea if these small areas are typical or rare. The Hubble observations give us a broader view because the telescope is looking along a longer and wider path. So Hubble gives context to what each Voyager is passing through.”

The combined data is also providing new insights into how our Sun travels through interstellar space, and astronomers hope that these combined observations will help them characterize the physical properties of the local interstellar medium.

“Ideally, synthesizing these insights with in situ measurements from Voyager would provide an unprecedented overview of the local interstellar environment,” said Hubble team member Julia Zachary of Wesleyan University.

The initial look at the clouds’ composition shows very small variations in the abundances of the chemical elements contained in the structures.

“These variations could mean the clouds formed in different ways, or from different areas, and then came together,” Redfield said.

In this illustration, NASA’s Hubble Space Telescope is looking along the paths of NASA’s Voyager 1 and 2 spacecraft as they journey through the solar system and into interstellar space. Hubble is gazing at two sight lines (the twin cone-shaped features) along each spacecraft’s path. The telescope’s goal is to help astronomers map interstellar structure along each spacecraft’s star-bound route. Each sight line stretches several light-years to nearby stars. Credit: NASA, ESA, and Z. Levy (STScI).

Astronomers are also seeing that the region that we and our solar system are passing through right now contains “clumpier” material, which may affect the heliosphere, the large bubble that is produced by our Sun’s powerful solar wind. At its boundary, called the heliopause, the solar wind pushes outward against the interstellar medium. Hubble and Voyager 1 made measurements of the interstellar environment beyond this boundary, where the wind comes from stars other than our sun.

“I’m really intrigued by the interaction between stars and the interstellar environment,” Redfield said. “These kinds of interactions are happening around most stars, and it is a dynamic process.”

Both Voyagers 1 and 2 launched in 1977 and both explored Jupiter and Saturn. Voyager 2 went on to visit Uranus and Neptune.

Voyager 1 is now 13 billion miles (20 billion km) from Earth, and entered interstellar space in 2012, the region between the stars that is filled with gas, dust, and material recycled from dying stars. It is the farthest a human-made spacecraft has even traveled. Next big ‘landmark’ for Voyager 2 is in about 40,000 years when it will come within 1.6 light-years of the star Gliese 445, in the constellation Camelopardalis.

Voyager 2, is 10.5 billion miles (16.9 billion km) from Earth, and will pass 1.7 light-years from the star Ross 248 in about 40,000 years.

Of course, neither spacecraft will be operational by then.

But scientists hope that for at least the next 10 years, the Voyagers will be making measurements of interstellar material, magnetic fields, and cosmic rays along their trajectories. The complimentary Hubble observations will help to map interstellar structure along the routes. Each sight line stretches several light-years to nearby stars. Sampling the light from those stars, Hubble’s Space Telescope Imaging Spectrograph measured how interstellar material absorbed some of the starlight, leaving telltale spectral fingerprints.

When the Voyagers run out of power and are no longer able to communicate with Earth, astronomers still hope to use observations from Hubble and subsequent space telescopes to characterize the environment where our robotic emissaries to the cosmos will travel.

Source: HubbleSite

Europa’s Venting Global Ocean May Be Easier To Reach Than We Thought

Artist's impression of a water vapor plume on Europa. Credit: NASA/ESA/K. Retherford/SWRI

Last week, on Tuesday, September 20th, NASA announced that they had made some interesting findings about Jupiter’s icy moon Europa. These were based on images taken by the Hubble Space Telescope, the details of which would be released on the following week. Needless to say, since then, the scientific community and general public have been waiting with baited breath.

Earlier today (September 26th) NASA put an end to the waiting and announced the Hubble findings during a NASA Live conference. According to the NASA panel, which was made up of members of the research team, this latest Europa-observing mission revealed evidence of plumes of saline water emanating from Europa’s surface. If true, this would mean that the moon’s subsurface ocean would be more accessible than previously thought.

Using Hubble’s Space Telescope Imaging Spectrograph (STIS) instrument, the team conducted observations of Jupiter and Europa in the ultra-violet spectrum over the course of 15 months. During that time, Europa passed in front of Jupiter (occulted the gas giant) on 10 separate occasions.

And on three of these occasions, the team saw what appeared to be plumes of water erupting from the surface. These plumes were estimated to be reaching up to 200 km (125 miles) from the southern region of Europa before (presumably) raining back onto the surface, depositing water ice and material from the interior.

The purpose of the observation was to examine Europa’s possible extended atmosphere (aka. exosphere). The method the team employed was similar to the one used to detect atmospheres around extra-solar planets. As William Sparks of the Space Telescope Science Institute (STScI) in Baltimore (and the team leader), explained in a NASA press release:

“The atmosphere of an extrasolar planet blocks some of the starlight that is behind it. If there is a thin atmosphere around Europa, it has the potential to block some of the light of Jupiter, and we could see it as a silhouette. And so we were looking for absorption features around the limb of Europa as it transited the smooth face of Jupiter.”

When they looked at Europa using this same technique, they noted that small patches on the surface were dark, indicating the absorption of UV light. This corresponded to previous work done by Lorenz Roth (of the Southwest Research Institute) and his team of researchers in 2012. At this time, they detected evidence of water vapor coming from Europa’s southern polar region.

Europa transit illustration. Europa orbits Jupiter every 3 and a half days, and on every orbit it passes in front of Jupiter, raising the possibility of plumes being seen as silhouettes absorbing the background light of Jupiter. Credits: A. Field (STScI)
Europa transit illustration. Europa orbits Jupiter every 3 and a half days, and on every orbit it passes in front of Jupiter, raising the possibility of plumes being seen as silhouettes absorbing the background light of Jupiter. Credits: A. Field (STScI)

As they indicated in a paper detailing their results – titled “Transient Water Vapor at Europa’s South Pole” – Roth’s team also relied on UV observations made using the Hubble telescope. Noting a statistically coincident amount of hydrogen and oxygen emissions, they concluded that this was the result of ejected water vapor being broken apart by Jupiter’s radiation (a process known as radiolysis).

Though their methods differed, Sparks and his research team also found evidence of these apparent water plumes, and in the same place no less. Based on the latest information from STIS, most of the apparent plumes are located in the moon’s southern polar region while another appears to be located in the equatorial region.

“When we calculate in a completely different way the amount of material that would be needed to create these absorption features, it’s pretty similar to what Roth and his team found,” Sparks said. “The estimates for the mass are similar, the estimates for the height of the plumes are similar. The latitude of two of the plume candidates we see corresponds to their earlier work.”

Another interesting conclusion to come from this and the 2012 study is the likelihood that these water plumes are intermittent. Basically, Europa is tidally-locked world, which means the same side is always being presented to us when it transits Jupiter. This occus once every 3.5 days, thus giving astronomers and planetary scientists plenty of viewing opportunities.

 This composite image shows suspected plumes of water vapor erupting at the 7 o’clock position off the limb of Jupiter’s moon Europa. The Hubble data were taken on January 26, 2014. Credit: Credits: NASA/ESA/W. Sparks (STScI)/USGS Astrogeology Science Center
This composite image shows suspected plumes of water vapor erupting at the 7 o’clock position off the limb of Jupiter’s moon Europa. The Hubble data were taken on January 26, 2014. Credit: Credits: NASA/ESA/W. Sparks (STScI)/USGS Astrogeology Science Center

But the fact that plumes have been observed at some points and not others would seem to indicate that they are periodic. In addition, Roth’s team attempted to spot one of the plume’s observed by Sparks and his colleagues a week after they reported it. However, they were unable to locate this supposed water source. As such, it would appear that the plumes, if they do exist, are short-lived.

These findings are immensely significant for two reasons. On the one hand, they are further evidence that a warm-water, saline ocean exists beneath Europa’s icy surface. On the other, they indicate that any future mission to Europa would be able to access this salt-water ocean with greater ease.

Ever since the Galileo spacecraft conducted a flyby of the Jovian moon, scientists have believed that an interior ocean is lying beneath Europa’s icy surface – one that has between two and three times as much water as all of Earth’s oceans combined. However, estimates of the ice’s thickness range from it being between 10 to 30 km (6–19 mi) thick – with a ductile “warm ice” layer that increases its total thickness to as much as 100 km (60 mi).

Knowing the water periodically reaches the surface through fissures in the ice would mean that any future mission (which would likely include a submarine) would not have to drill so deep. And considering that Europa’s interior ocean is considered to be one of our best bets for finding extra-terrestrial life, knowing that the ocean is accessible is certainly exciting news.

A comparison of 2014 transit and 2012 Europa aurora observations. The raw transit image, left, has dark fingers or patches of possible absorption in the same place that a different team (led by Lorenz Roth) found auroral emission from hydrogen and oxygen, the dissociation products of water. Credits: NASA, ESA, W. Sparks (left image) L. Roth (right image)
A comparison of 2014 transit and 2012 Europa aurora observations. Credits: NASA, ESA, W. Sparks (left image) L. Roth (right image)

And the news is certainly causing its fair share of excitement for the people who are currently developing NASA’s proposed Mission to Europa, which is scheduled to launch sometime in the 2020s. As Dr. Cynthia B. Phillips, a Staff Scientist and the Science Communications Lead for the Europa Project, told Universe Today via email:

“This new discovery, using Hubble Space Telescope data, is an intriguing data point that helps lend support to the idea that there are active plumes on Europa today. While not an absolute confirmation, the new Sparks et al. result, in combination with previous observations by Roth et al. (also using HST but with a different technique), is consistent with the presence of intermittent plumes ejecting water vapor from the Southern Hemisphere of Europa. Such observations are difficult to perform from Earth, however, even with Hubble, and thus these results remain inconclusive.

“Confirming the presence or absence of plumes on Europa, as well as investigating many other mysteries of this icy ocean world, will require a dedicated spacecraft in the Jupiter system.   NASA currently plans to send a multiple-flyby spacecraft to Europa, which would make many close passes by Europa in the next decade. The spacecraft’s powerful suite of scientific instruments will be able to study Europa’s surface and subsurface in unprecedented detail, and if plumes do exist, it will be able to observe them directly and even potentially measure their composition.  Until the Europa spacecraft is in place, however, Earth-based observations such as the new Hubble Space Telescope results will remain our best technique to observe Jupiter’s mysterious moon.”

Naturally, Sparks was clear that this latest information was not entirely conclusive. While he believes that the results were statistically significant, and that there were no indications of artifacts in the data, he also emphasized that observations conducted in the UV wavelength are tricky. Therefore, more evidence is needed before anything can be said definitively.

In the future, it is hoped that future observation will help to confirm the existence of water plumes, and how these could have helped create Europa’s “chaos terrain”. Future missions, like NASA’s James Webb Space Telescope (scheduled to launch in 2018) could help confirm plume activity by observing the moon in infrared wavelengths.

As Paul Hertz, the director of the Astrophysics Division at NASA Headquarters in Washington, said:

“Hubble’s unique capabilities enabled it to capture these plumes, once again demonstrating Hubble’s ability to make observations it was never designed to make. This observation opens up a world of possibilities, and we look forward to future missions — such as the James Webb Space Telescope — to follow up on this exciting discovery.”

Other team members include Britney Schmidt, an assistant professor at the School of Earth and Atmospheric Sciences at Georgia Institute of Technology in Atlanta; and Jennifer Wiseman, senior Hubble project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Their work will be published in the Sept. 29 issue of the Astrophysical Journal.

And be sure to enjoy this video by NASA about this exciting find:

Further Reading: NASA Live

Hubble Detects A Planet Around Binary Star System

This artist's illustration shows a planet circling a pair of distant red dwarf stars, representing the the system OGLE-2007-BLG-349 system, about 8,000 lightyears from Earth. Credit: NASA, ESA, and G. Bacon (STScI).

Binary stars are common throughout the galaxy, as it has been estimated about half the stars in our sky consist of two stars orbiting each other. Therefore, it’s also thought that about half of all exoplanet host stars are binaries as well. However, only about 10 of these so called circumbinary planets have been found so far in the 3,000-plus confirmed extrasolar planets that have been discovered.

But chalk up one more circumbinary planet, and this one bodes well for a technique that could help scientists find planets that orbit far away from their stars. Astronomers using the Hubble Space Telescope have confirmed a very interesting “three-body” system where two very close stars have a planet that orbits them both at a rather large distance.

The two red dwarf stars are just 7 million miles apart, or about 14 times the diameter of the Moon’s orbit around Earth. The planet orbits roughly 300 million miles from the stellar duo, about the distance of the asteroid belt from the Sun. The planet completes an orbit around both stars roughly every seven years.

Will China's new space telescope out-perform the Hubble? Image:
The Hubble Space Telescope. Image: NASA

Hubble used the a technique called gravitational microlensing, where the gravity of a foreground star bends and amplifies the light of a background star that momentarily aligns with it. The light magnification can reveal clues to the nature of the foreground star and any associated planets.

The system, called OGLE-2007-BLG-349, was originally detected in 2007 by the Optical Gravitational Lensing Experiment (OGLE), a telescope at the Las Campanas Observatory in Chile that searches for and observes microlensing effects from small distortions of spacetime, caused by stars and exoplanets.

However, the original OGLE observations could not confirm the details of the OGLE-2007-BLG-349 system. OGLE and several other ground-based observations determined there was a star and a planet in this system, but they couldn’t positively identify what the observed third body was.

“The ground-based observations suggested two possible scenarios for the three-body system: a Saturn-mass planet orbiting a close binary star pair or a Saturn-mass and an Earth-mass planet orbiting a single star,” said David Bennett, from NASA’s Goddard Space Flight Center, who is the first author in a new paper about the system, to be published in the Astrophysical Journal.

With Hubble’s sharp eyesight, the research team was able to separate the background source star and the lensing star from their neighbors in the very crowded star field. The Hubble observations revealed that the starlight from the foreground lens system was too faint to be a single star, but it had the brightness expected for two closely orbiting red dwarf stars, which are fainter and less massive than our sun.

“So, the model with two stars and one planet is the only one consistent with the Hubble data,” Bennett said.
“OGLE has detected over 17,000 microlensing events, but this is the first time such an event has been caused by a circumbinary planetary system,” explains Andrzej Udalski from the University of Warsaw, Poland, co-author of the study and leader of the OGLE project.

The team said this first-ever confirmation of an exoplanet system using the gravitational microlensing technique suggests some intriguing possibilities. While data from the Kepler Space Telescope is more likely to reveal planets that orbit close to their stars, microlensing allows planets to be found at distances far from their host stars.

“This discovery, suggests we need to rethink our observing strategy when it comes to stellar binary lensing events,” said Yiannis Tsapras, another member of the team, from the Astronomisches Recheninstitut in Heidelberg, Germany. “This is an exciting new discovery for microlensing”.

The team said that since this observation has shown that microlensing can successfully detect circumbinary planets, Hubble could provide an essential new role in the continued search for exoplanets.

OGLE-2007-BLG-349 is located 8,000 light-years away, towards the center of our galaxy.

(And, you’re welcome… I didn’t mention Tatooine in this article, until now!)

Further reading: Hubblesite, ESA Hubble,

Hubble’s Surprising Find On Europa To Be Announced By NASA Monday

Europa as imaged by the Galileo spacecraft. Europa is a prime target in the search for life because of its sub-surface ocean. Image: NASA/JPL-Caltech/SETI Institute

NASA will make a “surprising” announcement about Jupiter’s moon Europa on Monday, Sept. 26th, at 2:00 PM EDT. They haven’t said much, other than there is “surprising evidence of activity that may be related to the presence of a subsurface ocean on Europa.” Europa is a prime target for the search for life because of its subsurface ocean.

The new evidence is from a “unique Europa observing campaign” aimed at the icy moon. The Hubble Space Telescope captured the images in these new findings, so maybe we’ll be treated to some more of the beautiful images that we’re accustomed to seeing from the Hubble.

Images from NASA's Galileo spacecraft show the intricate detail of Europa's icy surface. Image: NASA/JPL-Caltech/ SETI Institute
Images from NASA’s Galileo spacecraft show the intricate detail of Europa’s icy surface. Image: NASA/JPL-Caltech/ SETI Institute

We always welcome beautiful images, of course. But the real interest in Europa lies in its suitability for harboring life. Europa has a frozen surface, but underneath that ice there is probably an ocean. The frozen surface is thought to be about 10 – 30 km thick, and the ocean may be about 100 km (62 miles) thick. That’s a lot of water, perhaps double what Earth has, and that water is probably salty.

Back in 2012, the Hubble captured evidence of plumes of water vapor escaping from Europa’s south pole. Hubble didn’t directly image the water vapor, but it “spectroscopically detected auroral emissions from oxygen and hydrogen” according to a NASA news release at the time.

This artist's illustration shows what plumes of water vapour might look like being ejected from Europa's south pole. Image: NASA, ESA, L. Roth (Southwest Research Institute, USA/University of Cologne, Germany) and M. Kornmesser.
This artist’s illustration shows what plumes of water vapour might look like being ejected from Europa’s south pole. Image: NASA, ESA, L. Roth (Southwest Research Institute, USA/University of Cologne, Germany) and M. Kornmesser.

There are other lines of evidence that support the existence of a sub-surface ocean on Europa. But there are a lot of questions. Will the frozen top layer be several tens of kilometres thick, or only a few hundred meters thick? Will the sub-surface ocean be warm, liquid water? Or will it be frozen too, but warmer than the surface ice and still convective?

Two models of the interior of Europa. Image: NASA/JPL.
Two models of the interior of Europa. Image: NASA/JPL.

Hopefully, new evidence from the Hubble will answer these questions definitively. Stay tuned to Monday’s teleconference to find out what NASA has to tell us.

These are the scientists who will be involved in the teleconference:

  • Paul Hertz, director of the Astrophysics Division at NASA Headquarters in Washington
  • William Sparks, astronomer with the Space Telescope Science Institute in Baltimore
  • Britney Schmidt, assistant professor at the School of Earth and Atmospheric Sciences at Georgia Institute of Technology in Atlanta
  • Jennifer Wiseman, senior Hubble project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland

The NASA website will stream audio from the teleconference.

More About Europa:

Hubble Captures The Sharpest Image Of A Disintegrating Comet Ever

Comet 332P breakup. Credit: NASA, ESA, and D. Jewitt (UCLA)
This NASA Hubble Space Telescope image reveals the ancient Comet 332P/Ikeya-Murakami disintegrating as it approaches the sun. The observations represent one of the sharpest views of an icy comet breaking apart. The comet debris consists of a cluster of building-size chunks near the center of the image. They form a 3,000-mile-long trail, larger than the width of the continental U.S. The fragments are drifting away from the comet at a leisurely pace, roughly the walking speed of an adult. The main nucleus of Comet 332P is the bright object at lower left. It measures 1,600 feet across, about the length of five football fields. Credit: NASA, ESA, and D. Jewitt (UCLA)
This Hubble Space Telescope image reveals the ancient Comet 332P/Ikeya-Murakami disintegrating as it approaches the sun. The comet debris consists of a cluster of building-size chunks near the center of the image. They form a trail larger than the width of the continental U.S. The fragments are drifting away from the comet at a leisurely pace of just a few miles an hour. The main nucleus of Comet 332P is the bright object at lower left. It measures 1,600 feet across, about the length of five football fields. Credit: NASA, ESA, and D. Jewitt (UCLA)

Breaking up isn’t hard to do if you’re a comet. They’re fragile creatures subject to splitting, cracking and vaporizing when heated by the Sun and yanked on by its powerful gravitational pull.

Recently, the Hubble Space Telescope captured one of the sharpest, most detailed observations of a comet breaking apart, which occurred 67 million miles from Earth. In a series of images taken over a three-day span in January 2016, Hubble revealed 25 building-size blocks made of a mixture of ice and dust that are drifting away from the main nucleus of the periodic comet 332P/Ikeya-Murakami at a leisurely pace, about the walking speed of an adult.

332P on UT 2016 January 26, 27 and 28, showing fragments measured in this work. The images are displayed consecutively as an animated gif in order to show the motion of the fragments relative to the parent nucleus (visible as the bright object to the lower left). The actual motions are very slow, of order 1 m/s, and show a fan-like divergence from the parent. Notice that some of the fragments also change in brightness and even shape from day to day. We think this is due to continuing outgassing, rotation and breakup of the fragments.
This animation shows the movement of individual comet fragments relative to the parent nucleus, the bright object at lower left, on January 26, 27 and 28 UT. The true motions are very slow, on the order of several miles an hour, and show a fan-like divergence from the parent. Look closely and you’ll see that some of the fragments change in brightness and even shape from day to day. Researcher David Jewitt thinks this is due to continuing outgassing, rotation and breakup of the fragments. Credit: NASA, ESA, and D. Jewitt (UCLA)

The observations suggest that the comet may be spinning so fast that material is ejected from its surface. The resulting debris is now scattered along a 3,000-mile-long trail, larger than the width of the continental U.S. Much the same happens with small asteroids, when sunlight absorbed unequally across an asteroid’s surface spins up its rotation rate, either causing it to fall apart or fling hunks of itself into space.

Being made of loosely bound frothy ice, comets may be even more volatile compared to the dense rocky composition of many asteroids. The research team suggests that sunlight heated up the comet, causing jets of gas and dust to erupt from its surface. We see this all the time in comets in dramatic images taken by the Rosetta spacecraft of Comet 67P/Churyumov-Gerasimenko. Because the nucleus is so small, these jets act like rocket engines, spinning up the comet’s rotation. The faster spin rate loosened chunks of material, which are drifting off into space.

Comet 168P-Hergenrother was imaged by the Gemini telescope on Nov. 2, 2012 at about 6 a.m. UTC. Image Credit: NASA/JPL-Caltech/Gemini
Comet 168P/Hergenrother was photographed by the Gemini telescope on Nov. 2, 2012 and shows three fragments that broke away from the nucleus streaming from the coma down the tail. Credit: NASA/JPL-Caltech/Gemini

“We know that comets sometimes disintegrate, but we don’t know much about why or how they come apart,” explained lead researcher David Jewitt of the University of California at Los Angeles. “The trouble is that it happens quickly and without warning, and so we don’t have much chance to get useful data. With Hubble’s fantastic resolution, not only do we see really tiny, faint bits of the comet, but we can watch them change from day to day. And that has allowed us to make the best measurements ever obtained on such an object.”

In the animation you can see the comet splinters brighten and fade as icy patches on their surfaces rotate in and out of sunlight. Their shapes even change! Being made of ice and crumbly as a peanut butter cookie, they continue to break apart to spawn a host of smaller cometary bits. The icy relics comprise about 4% of the parent comet and range in size from roughly 65 feet wide to 200 feet wide (20-60 meters). They are moving away from each other at a few miles per hour.

Crack on 67P - a sign of a coming breakup?
The European Space Agency’s Rosetta probe photographed this big crack in the neck region of the double-lobed comer 67P. It’s several feet wide and about 700 feet long. Could it be an indicator that the comet will break into two in the future? Credit: ESA/Rosetta

Comet 332P was slightly beyond the orbit of Mars when Hubble spotted the breakup. The surviving bright nucleus completes a rotation every 2-4 hours, about four times as fast as Comet 67P/Churyumov-Gerasimenko (a.k.a. “Rosetta’s Comet”). Standing on its surface you’d see the sun rise and set in about an hour, akin to how frequently astronauts aboard the International Space Station see sunsets and sunrises orbiting at over 17,000 mph.

Don’t jump for joy though. Since the comet’s just 1,600 feet (488 meters) across, its gravitational powers are too meek to allow visitors the freedom of hopping about lest they find themselves hovering helplessly in space above the icy nucleus.

This illustration shows one possible explanation for the disintegration of asteroid P/2013 R3. It is likely that over the past 4.5 billion years the asteroid was fractured by collisions with other asteroids. The effects of sunlight will have caused the asteroid to slowly increase its rotation rate until the loosely bound fragments drifted apart due to centrifugal forces. Dust drifting off the pieces makes the comet-looking tails. This process may be common for small bodies in the asteroid belt.
This illustration shows one possible explanation for the disintegration of asteroids and comets. The effects of sunlight can cause an asteroid to slowly increase its rotation rate until the loosely bound fragments drift apart due to centrifugal forces. In the case of comets, jets of vaporizing ice have a rocket-like effect that can spin up a nucleus to speeds fast enough for the comet to eject pieces of itself. Credit: NASA, ESA, D. Jewitt (UCLA), and A. Feild (STScI)

Comet 332P was discovered in November 2010, after it surged in brightness and was spotted by two Japanese amateur astronomers, Kaoru Ikeya and Shigeki Murakami. Based on the Hubble data, the team calculated that the comet probably began shedding material between October and December 2015. From the rapid changes seen in the shards over the three days captured in the animation, they probably won’t be around for long.


Spectacular breakup of Comet 73P in 2006

More changes may be in the works. Hubble’s sharp vision also spied a chunk of material close to the comet, which may be the first salvo of another outburst. The remnant from still another flare-up, which may have occurred in 2012, is also visible. The fragment may be as large as Comet 332P, suggesting the comet split in two.

“In the past, astronomers thought that comets die when they are warmed by sunlight, causing their ices to simply vaporize away,” Jewitt said. “Either nothing would be left over or there would be a dead hulk of material where an active comet used to be. But it’s starting to look like fragmentation may be more important. In Comet 332P we may be seeing a comet fragmenting itself into oblivion.”


During its closest approach to the Sun on November 28, 2013, Comet ISON’s nucleus broke apart and soon vaporized away, leaving little more than a ghostly head and fading tail.

Astronomers using the Hubble and other telescopes have seen breakups before, most notably in April 2006 when 73P/Schwassmann-Wachmann 3, which crumbled into more than 60 pieces.  Unlike 332P, the comet wasn’t observed long enough to track the evolution of the fragments, but the images are spectacular!

The researchers estimate that Comet 332P contains enough mass to endure another 25 outbursts. “If the comet has an episode every six years, the equivalent of one orbit around the sun, then it will be gone in 150 years,” Jewitt said. “It’s the blink of an eye, astronomically speaking. The trip to the inner Solar System has doomed it.”

332P on UT 2016 January 26, 27 and 28, showing fragments measured in this work. The images are displayed consecutively as an animated gif in order to show the motion of the fragments relative to the parent nucleus (visible as the bright object to the lower left). The actual motions are very slow, of order 1 m/s, and show a fan-like divergence from the parent. Notice that some of the fragments also change in brightness and even shape from day to day. We think this is due to continuing outgassing, rotation and breakup of the fragments.NASA, ESA, and D. Jewitt (UCLA)
This annotated image shows the fragments measured by Jewitt and team and their direction of movement. Credit: NASA, ESA, and D. Jewitt (UCLA)

332P/Ikeya-Murakami hails from the Kuiper Belt, a vast swarm of icy asteroids and comets beyond Neptune. Leftover building blocks from early Solar System and stuck in a deep freeze in the Kuiper Belt, you’d think they’d be left alone to live their solitary, chilly lives but no. After nearly 4.5 billion years in this icy deep freeze, chaotic gravitational perturbations from Neptune kicked Comet 332P out of the Kuiper Belt.

As the comet traveled across the solar system, it was deflected by the planets, like a ball bouncing around in a pinball machine, until Jupiter’s gravity set its current orbit. Jewitt estimates that a comet from the Kuiper Belt gets tossed into the inner solar system every 40 to 100 years.

I wish I could tell you to grab your scope for a look, but 332P is currently fainter than 15th magnitude and located in Libra low in the southwestern sky at nightfall. Hopefully, we’ll see more images in the coming weeks and months as Jewitt and the team continue to follow the evolution of its icy scraps.

Two Nearby Potentially Habitable Planets Are Rocky Worlds

An artist’s depiction of planets transiting a red dwarf star in the TRAPPIST-1 System. Credit: NASA/ESA/STScl

When Hubble first observed the atmospheric conditions of an extrasolar planet in 2000, it opened up that entire field of study. Now, Hubble has conducted the first preliminary study of the atmospheres of Earth-sized, relatively nearby worlds and found “indications that increase the chances of habitability on two exoplanets,” say the researchers.

The planets, TRAPPIST-1b and TRAPPIST-1c, were discovered earlier this year and are approximately 40 light-years away. At the time of their discovery, it was unknown if the worlds were gas planets or rocky worlds, but Hubble’s most recent observations suggest that both planets have compact atmospheres, similar to those of rocky planets such as Earth, Venus, and Mars instead of thick, puffy atmospheres, similar to that of the gas planets like Jupiter.

“Now we can say that these planets are rocky. Now the question is, what kind of atmosphere do they have?” said Julien de Wit of the Massachusetts Institute of Technology, who led a team of scientists to observe the planets in near-infrared light using Hubble’s Wide Field Camera 3. “The plausible scenarios include something like Venus, with high, thick clouds and an atmosphere dominated by carbon dioxide, or an Earth-like atmosphere dominated by nitrogen and oxygen, or even something like Mars with a depleted atmosphere. The next step is to try to disentangle all these possible scenarios that exist for these terrestrial planets.”

Structure of the TRAPPIST-1 exosystem. The green is the star's habitable zone. Credit: Planetary Habitability Lab.
Structure of the TRAPPIST-1 exosystem. The green is the star’s habitable zone. Credit: Planetary Habitability Lab.

The exoplanets were originally discovered by the TRAPPIST telescope at ESO’s La Silla observatory in Chile, which, like the Kepler telescope, looks for planetary transits (TRAPPIST stands for Transiting Planets and Planetesimals Small Telescope) observing dips in a star’s light from planets passing in front of it from Earth’s point of view.

The star, TRAPPIST-1, is an ultracool dwarf star and is very small and dim. TRAPPIST-1b completes an orbit around the star in just 1.5 days and TRAPPIST-1c in 2.4 days, and the planets are between 20 and 100 times closer to their star than the Earth is to the sun. Both are tidally locked, where one side of these worlds might be hellish and uninhabitable, but conditions might permit a limited region of habitability on the other side. And because of the star’s faintness, researchers think that TRAPPIST-1c may be within the star’s habitable zone, where moderate temperatures could allow for liquid water to pool.

“A rocky surface is a great start for a habitable planet, but any life on the TRAPPIST-1 planets is likely to have a much harder time than life on Earth,” said Joanna Barstow, an astrophysicist at University College London, who was not involved with the research. “Of course, our ideas of habitability are very narrow because we only have one planet to look at so far, and life might well surprise us by flourishing in what we think of as unlikely conditions.”

The researchers used spectroscopy to decode the light and reveal clues to the chemical makeup of the planets’ atmospheres. While the content of the atmospheres is unknown and are scheduled for more observations, the low concentration of hydrogen and helium has scientists excited about the implications.

The team realized a rare double transit was going to take place, when the two planets would almost simultaneously pass in front of their star, but they only knew two weeks in advance. They took a chance, and taking advantage of Hubble’s ability to do observations on short notice, they wrote up a proposal in a day.

“We thought, maybe we could see if people at Hubble would give us time to do this observation, so we wrote the proposal in less than 24 hours, sent it out, and it was reviewed immediately,” de Wit said. “Now for the first time we have spectroscopic observations of a double transit, which allows us to get insight on the atmosphere of both planets at the same time.”

Using Hubble, the team recorded a combined transmission spectrum of TRAPPIST-1b and c, meaning that as first one planet then the other crossed in front of the star, they were able to measure the changes in wavelength as the amount of starlight dipped with each transit.

“The data turned out to be pristine, absolutely perfect, and the observations were the best that we could have expected,” de Wit says. “The force was certainly with us.”

“These initial Hubble observations are a promising first step in learning more about these nearby worlds, whether they could be rocky like Earth, and whether they could sustain life,” says Geoff Yoder, acting associate administrator for NASA’s Science Mission Directorate in Washington. “This is an exciting time for NASA and exoplanet research.”

The team’s paper was published in Nature.

Sources: MIT, NASA

The Hubble Constant Just Got Constantier

A team of astronomers using the Hubble Space Telescope have found that the current rate of expansion of the Universe could be almost 10 percent faster than previously thought. Image: NASA, ESA, A. Feild (STScI), and A. Riess (STScI/JHU)
A team of astronomers using the Hubble Space Telescope have found that the current rate of expansion of the Universe could be almost 10 percent faster than previously thought. Image: NASA, ESA, A. Feild (STScI), and A. Riess (STScI/JHU)

Just when we think we understand the Universe pretty well, along come some astronomers to upend everything. In this case, something essential to everything we know and see has been turned on its head: the expansion rate of the Universe itself, aka the Hubble Constant.

A team of astronomers using the Hubble telescope has determined that the rate of expansion is between five and nine percent faster than previously measured. The Hubble Constant is not some curiousity that can be shelved until the next advances in measurement. It is part and parcel of the very nature of everything in existence.

“This surprising finding may be an important clue to understanding those mysterious parts of the universe that make up 95 percent of everything and don’t emit light, such as dark energy, dark matter, and dark radiation,” said study leader and Nobel Laureate Adam Riess of the Space Telescope Science Institute and The Johns Hopkins University, both in Baltimore, Maryland.

But before we get into the consequences of this study, let’s back up a bit and look at how the Hubble Constant is measured.

Measuring the expansion rate of the Universe is a tricky business. Using the image at the top, it works like this:

  1. Within the Milky Way, the Hubble telescope is used to measure the distance to Cepheid variables, a type of pulsating star. Parallax is used to do this, and parallax is a basic tool of geometry, which is also used in surveying. Astronomers know what the true brightness of Cepheids are, so comparing that to their apparent brightness from Earth gives an accurate measurement of the distance between the star and us. Their rate of pulsation also fine tunes the distance calculation. Cepheid variables are sometimes called “cosmic yardsticks” for this reason.
  2. Then astronomers turn their sights on other nearby galaxies which contain not only Cepheid variables, but also Type 1a supernova, another well-understood type of star. These supernovae, which are of course exploding stars, are another reliable yardstick for astronomers. The distance to these galaxies is obtained by using the Cepheids to measure the true brightness of the supernovae.
  3. Next, astronomers point the Hubble at galaxies that are even further away. These ones are so distant, that any Cepheids in those galaxies cannot be seen. But Type 1a supernovae are so bright that they can be seen, even at these enormous distances. Then, astronomers compare the true and apparent brightnesses of the supernovae to measure out to the distance where the expansion of the Universe can be seen. The light from the distant supernovae is “red-shifted”, or stretched, by the expansion of space. When the measured distance is compared with the red-shift of the light, it yields a measurement of the rate of the expansion of the Universe.
  4. Take a deep breath and read all that again.

The great part of all of this is that we have an even more accurate measurement of the rate of expansion of the Universe. The uncertainty in the measurement is down to 2.4%. The challenging part is that this rate of expansion of the modern Universe doesn’t jive with the measurement from the early Universe.

The rate of expansion of the early Universe is obtained from the left over radiation from the Big Bang. When that cosmic afterglow is measured by NASA’s Wilkinson Microwave Anisotropy Probe (WMAP) and the ESA’s Planck satellite, it yields a smaller rate of expansion. So the two don’t line up. It’s like building a bridge, where construction starts at both ends and should line up by the time you get to the middle. (Caveat: I have no idea if bridges are built like that.)

This Hubble Telescope image shows one of the galaxies used in the study. It contains two types of stars used to measure distances between galaxies. The red circles are pulsing Cepheid variable stars, and the blue X is a Type 1a supernova. Image: NASA, ESA, and A. Riess (STScI/JHU)
This Hubble Telescope image shows one of the galaxies used in the study. It contains two types of stars used to measure distances between galaxies. The red circles are pulsing Cepheid variable stars, and the blue X is a Type 1a supernova. Image: NASA, ESA, and A. Riess (STScI/JHU)

“You start at two ends, and you expect to meet in the middle if all of your drawings are right and your measurements are right,” Riess said. “But now the ends are not quite meeting in the middle and we want to know why.”

“If we know the initial amounts of stuff in the universe, such as dark energy and dark matter, and we have the physics correct, then you can go from a measurement at the time shortly after the big bang and use that understanding to predict how fast the universe should be expanding today,” said Riess. “However, if this discrepancy holds up, it appears we may not have the right understanding, and it changes how big the Hubble constant should be today.”

Why it doesn’t all add up is the fun, and maybe maddening, part of this.

What we call Dark Energy is the force that drives the expansion of the Universe. Is Dark Energy growing stronger? Or how about Dark Matter, which comprises most of the mass in the Universe. We know we don’t know much about it. Maybe we know even less than that, and its nature is changing over time.

“We know so little about the dark parts of the universe, it’s important to measure how they push and pull on space over cosmic history,” said Lucas Macri of Texas A&M University in College Station, a key collaborator on the study.

The team is still working with the Hubble to reduce the uncertainty in measurements of the rate of expansion. Instruments like the James Webb Space Telescope and the European Extremely Large Telescope might help to refine the measurement even more, and help address this compelling issue.

Space Weather Causing Martian Atmospherics

Hubble Space Telescope view of a plume high in the martian atmosphere seen in May 1997. Credit: NASA/ESA
A curious plume-like feature was observed on Mars on 17 May 1997 by the Hubble Space Telescope. It is similar to the features detected by amateur astronomers in 2012, although appeared in a different location. Credit: JPL/NASA/STScI
A curious plume-like feature was observed on Mars on May 17, 1997 by the Hubble Space Telescope. It is similar to the features detected by amateur astronomers in 2012, although appeared in a different location. Credit: JPL/NASA/STScI

Strange plumes in Mars’ atmosphere first recorded by amateur astronomers four year ago have planetary scientists still scratching their heads. But new data from European Space Agency’s orbiting Mars Express points to coronal mass ejections from the Sun as the culprit.

Mystery plume in Mars’ southern hemisphere photographed by amateur astronomer Wayne Jaeschke on March 20, 2012. The feature extended between 310-620 miles and lasted for about 10 days.
Mystery plume in Mars’ southern hemisphere photographed and animated by amateur astronomer Wayne Jaeschke on March 20, 2012. The feature lasted for about 10 days. Credit: Wayne Jaeschke

On two occasions in 2012 amateurs photographed cloud-like features rising to altitudes of over 155 miles (250 km) above the same region of Mars. By comparison, similar features seen in the past haven’t exceeded 62 miles (100 km). On March 20th of that year, the cloud developed in less than 10 hours, covered an area of up to 620 x 310 miles (1000 x 500 kilometers), and remained visible for around 10 days.

Back then astronomers hypothesized that ice crystals or even dust whirled high into the Martian atmosphere by seasonal winds might be the cause. However, the extreme altitude is far higher than where typical clouds of frozen carbon dioxide and water are thought to be able to form.

Indeed at those altitudes, we’ve entered Mars’ ionosphere, a rarified region where what air there is has been ionized by solar radiation. At Earth, charged particles from the Sun follow the planet’s global magnetic lines of force into the upper atmosphere to spark the aurora borealis. Might the strange features observed be Martian auroras linked to regions on the surface with stronger-than-usual magnetic fields?

Mars has magnetized rocks in its crust that create localized, patchy magnetic fields (left). In the illustration at right, we see how those fields extend into space above the rocks. At their tops, auroras can form. Credit: NASA
Mars has magnetized rocks in its crust that create localized, patchy magnetic fields (left). In the illustration at right, we see how those fields extend into space above the rocks. At their tops, auroras can form. Credit: NASA

Once upon a very long time ago, Mars may have had a global magnetic field generated by electrical currents in a liquid iron-nickel core much like the Earth’s does today. In the current era, the Red Planet has only residual fields centered over regions of magnetic rocks in its crust.

Copyright: W. Jaeschke and D. Parker The top image shows the location of the mysterious plume on Mars, identified within the yellow circle (top image, south is up), along with different views of the changing plume morphology taken by W. Jaeschke and D. Parker on 21 March 21 2012.
The top image shows the location of the mysterious plume on Mars, identified within the yellow circle (top image, south is up), along with different views of the changing plume morphology on March 21, 2012. Copyright: W. Jaeschke and D. Parker

Instead of a single, planet-wide field that funnels particles from the Sun into the atmosphere to generate auroras, Mars is peppered with pockets of magnetism, each potentially capable of connecting with the wind of particles from the Sun to spark a modest display of the “northern lights.” Auroras were first discovered on Mars in 2004 by the Mars Express orbiter, but they’re faint compared to the plumes, which were too bright to be considered auroras.

Still, this was a step in the right direction. What was needed was some hard data of a possible Sun-Earth interaction which scientists ultimately found when they looked into plasma and solar wind measurements collected by Mars Express at the time. David Andrews of the Swedish Institute of Space Physics, lead author of a recent paper reporting the Mars Express results, found evidence for a large coronal mass ejection or CME from the Sun striking the martian atmosphere in the right place and at around the right time.

Examples of Earth-based observations of the mysterious plume seen on 21 March 2012 (top right) and of Mars Express solar wind observations during March and April 2012 (bottom right).
Earth-based observations of the plume on March 21, 2012 (top right) and of Mars Express solar wind observations during March and April 2012 (bottom right). The left-hand graphics show Mars as seen by Mars Express. Green represents the planet’s dayside and gray, the nightside. Magnetic areas of the crust are shown in blue and red. The white box indicates the area in which the plume observations were made. Together, these graphics show that the amateur observations were made during the martian daytime, along the dawn terminator, while the spacecraft observations were made along the dusk terminator, approximately half a martian ‘day’ later.The black line on Mars is the ground track of the Mars Express orbiter. The plot on the lower right shows Mars Express’s solar wind measurements. The peaks marked by the horizontal blue line indicate the increase in the solar wind properties as a result of the impact of the coronal mass ejection. Credit: Copyright: visual images: D. Parker (large Mars image and bottom inset) & W. Jaeschke (top inset). All other graphics courtesy D. Andrews

CMEs are enormous explosions of hot solar plasma — a soup of electrons and protons — entwined with magnetic fields that blast off the Sun and can touch off geomagnetic storms and auroras when they encounter the Earth and other planets.

“Our plasma observations tell us that there was a space weather event large enough to impact Mars and increase the escape of plasma from the planet’s atmosphere,” said Andrews. Indeed, the plume was seen along the day–night boundary, over a region of known strong crustal magnetic fields.

Locations of 19 auroral detections (white circles) made by the SPICAM instrument on Mars Express during 113 nightside orbits between 2004 and 2014, over locations already known to be associated with residual crustal magnetism. The data is superimposed on the magnetic field line structure (from NASA’s Mars Global Surveyor) where red indicates closed magnetic field lines, grading through yellow, green and blue to open field lines in purple. The auroral emissions are very short-lived, they are not seen to repeat in the same locations, and only occur near the boundary between open and closed magnetic field lines. Credit: ESA / Copyright Based on data from J-C. Gérard et al (2015)
Locations of 19 auroral detections (white circles) made by Mars Express during 113 nightside orbits between 2004 and 2014, over locations already known to be associated with residual crustal magnetism. The data is superimposed on the magnetic field line structure (from NASA’s Mars Global Surveyor) where red indicates closed magnetic field lines, grading through yellow, green and blue to open field lines in purple. The auroral emissions are very short-lived, they are not seen to repeat in the same locations. Credit: ESA / Copyright Based on data from J-C. Gérard et al (2015)

But again, a Mars aurora wouldn’t be expected to shine so brightly. That’s why Andrews thinks that the CME prompted a disturbance in the ionosphere large enough to affect dust and ice grains below:

“One idea is that a fast-traveling CME causes a significant perturbation in the ionosphere resulting in dust and ice grains residing at high altitudes in the upper atmosphere being pushed around by the ionospheric plasma and magnetic fields, and then lofted to even higher altitudes by electrical charging,” according to Andrews.

A colossal CME departs the Sun in February 2000. erupting filament lifted off the active solar surface and blasted this enormous bubble of magnetic plasma into space. Credit NASA/ESA/SOHO
A colossal CME, composed of a magnetized cloud of subatomic particles, departs the Sun in February 2000. Credit NASA/ESA/SOHO

With enough dust and ice twinkling high above the planet’s surface, it might be possible for observers on Earth to see the result as a wispy plume of light. Plumes appear to be rare on Mars as a search through the archives has revealed. The only other, seen by the Hubble Space Telescope in May 1997, occurred when a CME was hitting the Earth at the same time. Unfortunately, there’s no information from Mars orbiters at the time about its effect on that planet.

Observers on Earth and orbiters zipping around the Red Planet continue to monitor Mars for recurrences. Scientists also plan to use the webcam on Mars Express for more frequent coverage. Like a dog with a bone, once scientists get a bite on a tasty mystery, they won’t be letting go anytime soon.

Hubble Telescope Zooms In On Mars

Mars snapped with the Hubble Space Telescope on May 12 just days before opposition. Credit: NASA/ESA
This image shows our neighbouring planet Mars, as it was observed shortly before opposition in 2016 by the NASA/ESA Hubble Space Telescope. Some prominent features of the planet are clearly visible: the ancient and inactive shield volcano Syrtis Major; the bright and oval Hellas Planitia basin; the heavily eroded Arabia Terra in the centre of the image; the dark features of Sinus Sabaeous and Sinus Meridiani along the equator; and the small southern polar cap.
On May 12, the Hubble Space Telescope took this photo of Mars. Some prominent features of the planet are clearly visible: the ancient and inactive shield volcano Syrtis Major (far right and partly covered by clouds); the heavily eroded Arabia Terra in the center of the image; the dark features of Sinus Sabaeous and Sinus Meridiani below center and the small north polar cap (top).

We’re in store for an exciting weekend as the Earth and Mars get closer to each other than at any time in the last ten years. To take advantage of this special opportunity, the Hubble Space Telescope, normally busy eyeing remote galaxies, was pointed at our next door neighbor to capture this lovely close-up image.

Opposition occurs when Mars and Earth line up on the same side of the Sun. The two planets are closest together at that time. Mars opposition occurs on May 22, when the planet will shine at magnitude -2.0 and with an apparent diameter of 18.6 arc seconds, its largest in years. Credit: Bob King
Opposition occurs when Mars and Earth line up on the same side of the Sun. The two planets are closest together around that time. Mars opposition occurs on May 22, when the planet will shine at magnitude -2.0 and with an apparent diameter of 18.6 arc seconds, its largest in over 10 years. Credit: Bob King

As Universe Today writer David Dickinson described in his excellent Mars guide, the planet reaches opposition on Sunday morning May 22. That’s when the planet will be directly opposite the Sun in the sky and rise in the east around the same time the Sun sets in the west. Earth sits squarely in between. Opposition also marks the planet’s close approach to Earth, so that Mars appears bigger and brighter in the sky than usual. A perfect time for detailed studies whether through both amateur and professional telescopes.

Although opposition for most outer planets coincides with the date of closest approach, that’s not true in the case of Mars. If Mars is moving away from the Sun in its orbit when Earth laps it, closest approach occurs a few days before opposition.  But if the planet is moving toward the Sun when our planet passes by, closest approach occurs a few days after opposition. This time around, Mars is headed sunward, so the date of closest approach of the two planets occurs on May 30.

It’s all goes back to Mars’ more eccentric orbit, which causes even a few days worth of its orbital travels to make a difference in the distance between the two planets when Earth is nearby.  On May 22, Mars will be 47.4 million miles away vs. 46.77 million on the 30th, a difference of about 700,000 miles.

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Every 26 months Mars reaches opposition. This mosaic of photos taken by Hubble show seven different oppositions since 1995. Because of Mars’ elliptical orbit, it shows variations in apparent size from opposition to opposition.  Mars was the closest in 2003 when it came within 34.8 million miles (56 million kilometer) of Earth. The part of Mars that is tilted towards the Earth also shifts over time, resulting in the changing visibility of the polar caps. Clouds and dust storms, as well as the size of the ice caps, can change the appearance of Mars on time scales of days, weeks, and months. Other features of Mars, such as some of the large dark markings, have remained unchanged for centuries. Credit: NASA/ESA

On May 12, Hubble took advantage of this favorable alignment and turned its gaze towards Mars to take an image of our rusty-hued neighbor, From this distance the telescope could see Martian features as small as 18.6 miles (30 kilometers) across. The image shows a sharp, natural-color view of Mars and reveals several prominent geological features, from smaller mountains and erosion channels to immense canyons and volcanoes.

This image shows our neighbouring planet Mars, as it was observed shortly before opposition in 2016 by the NASA/ESA Hubble Space Telescope. Some prominent features on the surface of the planet have been annotated.
Some of the more prominent features in the Hubble photo of Mars are marked here. Limb hazes are visible in modest-sized telescopes as a pale edging around the planet’s rim. The planet’s distinctive red color is created by rust. Billions of years ago, it’s thought that ultraviolet light from the Sun split water in the Martian atmosphere into hydrogen and oxygen. The hydrogen escaped, but the oxygen combined with iron in the planet’s surface rocks to form iron oxide or rust. Many of Earth’s red rock formations are similarly “oxidized.” Credit: NASA/ESA

The orange area in the center of the image is Arabia Terra, a vast upland region. The landscape is densely cratered and heavily eroded, indicating that it could be among the oldest features on the planet.

While the polar caps aren't currently visible, telescope users will be treated to nice views of India-shaped Syrtis Major. The large crater Hellas at the top (south) limb is currently covered in winter clouds. Credit: Christopher Go
While the polar caps aren’t currently visible, telescope users will be treated to nice views of India-shaped Syrtis Major. The large crater Hellas at the top (south) limb is currently covered in winter clouds. Credit: Christopher Go

South of Arabia Terra, running east to west along the equator, is the long dark feature named Sinus Sabaeus that terminates in a larger, dark blob called and Sinus Meridiani. These darker regions are covered by bedrock from ancient lava flows and other volcanic features. An extended blanket of clouds can be seen over the southern polar cap where it’s late winter. The icy northern polar cap has receded to a comparatively small size because it’s now late summer in the northern hemisphere.

Mars on May 2 shows Syrtis Major off to the east (right). Crossing the top of the photo are Mare Tyrrhenum to the right of the planet's central meridian and Mare Cimmerium, to the left. Credit: Christopher Go
Mars on May 2 shows Syrtis Major off to the east (right). Crossing the top of the photo are Mare Tyrrhenum to the right of the planet’s central meridian and Mare Cimmerium, to the left. Credit: Christopher Go

So the question now is how much will you see as we pull up alongside the Red Planet this weekend? With the naked eye, Mars looks like a fiery “star” in the head of Scorpius the scorpion not far from the similarly-colored Antares, the brightest star in the constellation. It’s unmistakable. Even through the haze it caught my eye last night, rising in the southeast around 10 o’clock with its signature hue.

Through a 4-inch or larger telescope, you can see limb hazes/clouds and prominent dark features such as Syrtis Major, Utopia, clouds over Hellas, Mare Tyrrhenum (to the west of Syrtis Major) and Mare Cimmerium (west of M. Tyrrhenum).

Expert imager Damian Peach created this photographic map of Mars labeled with its most prominent features visible in amateur telescopes. Click for a larger version. Credit: Damian Peach
Expert astroimager Damian Peach created this photographic map of Mars labeled with its most prominent features visible in amateur telescopes. Click for a large version. Credit: Damian Peach

These features observers across the America will see this week and early next between about 11 p.m. and 2 a.m. local time. As Mars rotation period is 37 minutes longer than Earth’s, these markings will gradually rotate out of view, and we’ll see the opposite hemisphere in the coming weeks. You can use the map to help you identify particular features or Sky & Telescope’s handy Mars Profiler to know which side of the planet’s visible when.

The Full Moon, Mars only hours before opposition, Saturn and Antares gather in the southern sky for a special, diamond-shaped grouping. Diagram: Bob King, source: Stellarium
The Full Moon, Mars only hours before opposition, Saturn and Antares gather in the southern sky for a special, diamond-shaped grouping. Diagram: Bob King, source: Stellarium

To top off all the good stuff happening with Mars, the Full Flower Moon will join up with that planet, Saturn and Antares Saturday night May 21 to create what I like to call a “diamond of celestial lights” visible all night. Don’t miss it!

Italian astronomer Gianluca Masi will offer up two online Mars observing sessions in the coming week, on May 22 and 30, starting at 5 p.m. CDT (22:00 UT). Yet another opportunity to get acquainted with your inner Mars.