Can Humans Live on Mars?

Image caption: Curiosity is taking the first ever radiation measurements from the surface of another planet in order to determine if future human explorers can live on Mars – as she traverses the terrain of the Red Planet. Curiosity is looking back to her rover tracks and the foothills of Mount Sharp and the eroded rim of Gale Crater in the distant horizon on Sol 24 (Aug. 30, 2012). This panorama is featured on PBS NOVA ‘Ultimate Mars Challenge’ documentary which premiered on PBS TV on Nov. 14. RAD is located on the rover deck in this colorized mosaic stitched together from Navcam images by the image processing team of Ken Kremer & Marco Di Lorenzo. Credit: NASA / JPL-Caltech / Ken Kremer / Marco Di Lorenzo

Metallic robots constructed by ingenious humans can survive on Mars. But what about future human astronauts?

NASA’s plucky Mars Exploration Rover Opportunity has thrived for nearly a decade traversing the plains of Meridiani Planum despite the continuous bombardment of sterilizing cosmic and solar radiation from charged particles thanks to her radiation hardened innards.

How about humans? What fate awaits them on a bold and likely year’s long expedition to the endlessly extreme and drastically harsh environment on the surface of the radiation drenched Red Planet – if one ever gets off the ground here on Earth? How much shielding would people need?

Answering these questions is one of the key quests ahead for NASA’s SUV sized Curiosity Mars rover – now 100 Sols, or Martian days, into her 2 year long primary mission phase.

Preliminary data looks promising.

Curiosity survived the 8 month interplanetary journey and the unprecedented sky crane rocket powered descent maneuver to touch down safely inside Gale Crater beside the towering layered foothills of 3 mi. (5.5 km) high Mount Sharp on Aug. 6, 2012.

Now she is tasked with assessing whether Mars and Gale Crater ever offered a habitable environment for microbial life forms – past or present. Characterizing the naturally occurring radiation levels stemming from galactic cosmic rays and the sun will address the habitability question for both microbes and astronauts. Radiation can destroy near-surface organic molecules.

Researchers are using Curiosity’s state-of-the-art Radiation Assessment Detector (RAD) instrument to monitor high-energy radiation on a daily basis and help determine the potential for real life health risks posed to future human explorers on the Martian surface.

“The atmosphere provides a level of shielding, and so charged-particle radiation is less when the atmosphere is thicker,” said RAD Principal Investigator Don Hassler of the Southwest Research Institute in Boulder, Colo. See the data graphs herein.

“Absolutely, the astronauts can live in this environment. It’s not so different from what astronauts might experience on the International Space Station. The real question is if you add up the total contribution to the astronaut’s total dose on a Mars mission can you stay within your career limits as you accumulate those numbers. Over time we will get those numbers,” Hassler explained.

The initial RAD data from the first two months on the surface was revealed at a media briefing for reporters on Thursday, Nov. 15 and shows that radiation is somewhat lower on Mars surface compared to the space environment due to shielding from the thin Martian atmosphere.

Image caption: Longer-Term Radiation Variations at Gale Crater. This graphic shows the variation of radiation dose measured by the Radiation Assessment Detector on NASA’s Curiosity rover over about 50 sols, or Martian days, on Mars. (On Earth, Sol 10 was Sept. 15 and Sol 60 was Oct. 6, 2012.) The dose rate of charged particles was measured using silicon detectors and is shown in black. The total dose rate (from both charged particles and neutral particles) was measured using a plastic scintillator and is shown in red. Credit: NASA/JPL-Caltech/ SwRI

RAD hasn’t detected any large solar flares yet from the surface. “That will be very important,” said Hassler.

“If there was a massive solar flare that could have an acute effect which could cause vomiting and potentially jeopardize the mission of a spacesuited astronaut.”

“Overall, Mars’ atmosphere reduces the radiation dose compared to what we saw during the cruise to Mars by a factor of about two.”

RAD was operating and already taking radiation measurements during the spacecraft’s interplanetary cruise to compare with the new data points now being collected on the floor of Gale Crater.

Mars atmospheric pressure is a bit less than 1% of Earth’s. It varies somewhat in relation to atmospheric cycles dependent on temperature and the freeze-thaw cycle of the polar ice caps and the resulting daily thermal tides.

“We see a daily variation in the radiation dose measured on the surface which is anti-correlated with the pressure of the atmosphere. Mars atmosphere is acting as a shield for the radiation. As the atmosphere gets thicker that provides more of a shield. Therefore we see a dip in the radiation dose by about 3 to 5%, every day,” said Hassler.

Image Caption: Curiosity Self Portrait with Mount Sharp at Rocknest ripple in Gale Crater. Curiosity used the Mars Hand Lens Imager (MAHLI) camera on the robotic arm to image herself and her target destination Mount Sharp in the background. Mountains in the background to the left are the northern wall of Gale Crater. This color panoramic mosaic was assembled from raw images snapped on Sol 85 (Nov. 1, 2012). Credit: NASA/JPL-Caltech/MSSS/Ken Kremer/Marco Di Lorenzo

There are also seasonal changes in radiation levels as Mars moves through space.

The RAD team is still refining the radiation data points.

“There’s calibrations and characterizations that we’re finalizing to get those numbers precise. We’re working on that. And we’re hoping to release that at the AGU [American Geophysical Union] meeting in December.”

Image caption: Daily Cycles of Radiation and Pressure at Gale Crater. This graphic shows the daily variations in Martian radiation and atmospheric pressure as measured by NASA’s Curiosity rover. As pressure increases, the total radiation dose decreases. When the atmosphere is thicker, it provides a better barrier with more effective shielding for radiation from outside of Mars. At each of the pressure maximums, the radiation level drops between 3 to 5 percent. The radiation level goes up at the end of the graph due to a longer-term trend that scientists are still studying. Credit: NASA/JPL-Caltech/SwRI

Radiation is a life limiting factor to habitability. RAD is the first science instrument to directly measure radiation from the surface of a planet other than Earth.

“Curiosity is finding that the radiation environment on Mars is sensitive to Mars weather and climate,” Hassler concluded.

Unlike Earth, Mars lost its magnetic field some 3.5 billion years ago – and therefore most of its shielding capability from harsh levels of energetic particle radiation from space.

Much more data will need to be collected by RAD before any final conclusions on living on Mars, and for how long and in which type habitats, can be drawn.

Learn more about Curiosity and NASA missions at my upcoming free public presentations:

And be sure to watch the excellent PBS NOVA Mars documentary – ‘Ultimate Mars Challenge’ – which also features Curiosity mosaics created by the imaging team of Ken Kremer & Marco Di Lorenzo.

Ken Kremer

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Dec 6: Free Public lecture titled “Atlantis, The Premature End of America’s Shuttle Program and What’s Beyond for NASA” including Curiosity, Orion, SpaceX and more by Ken Kremer at Brookdale Community College/Monmouth Museum and STAR Astronomy club in Lincroft, NJ at 8 PM

Dec 11: Free Public lecture titled “Curiosity and the Search for Life on Mars (in 3 D)” and more by Ken Kremer at Princeton University and the Amateur Astronomers Association of Princeton (AAAP) in Princeton, NJ at 8 PM.

Change of Command on the Space Station

Before the crew of Expedition 32/33 comes home today, astronaut and commander Suni Williams handed over the reins of the International Space Station to Kevin Ford during the traditional change of command ceremony … which was not so traditional. Williams handed out gifts to the new crew, and at times seemed quite emotional. Last week Williams wrote in her blog that she really didn’t want to think about leaving the ISS. “Up to this point I haven’t, and sort of denied it,” she wrote. “And, I am still in denial, but I am going thru the motions because I don’t want to forget something when the hatch closes.”

Williams, Aki Hoshide of the Japanese Aerospace Exploration Agency, and Russian cosmonaut Yuri Malenchenko will return home after what seems like a short 125 days in space, arriving at the ISS on July 17.

They will leave the station today (Sunday, Nov 18), undocking at 22:26 UTC (5:26 p.m. EST) Sunday and land in Kazakhstan at 01:53 UTC on Monday (8:53 p.m EST Sunday). You can watch live coverage on NASA TV.

Remaining onboard the ISS to begin Expedition 34 are Ford, Oleg Novitskiy and Evgeny Tarelkin. They will be joined by Chris Hadfield of the Canadian Space Agency, Russian cosmonaut Roman Romanenko, and NASA’s Tom Marshburn on Dec. 21 to bring the ISS crew compliment back to six. As Ford notes in the video, the new crew are “newbies” with a combined in-space experience of about 3 months, while Williams and her crew have a combined time in space of about 3 years.

JAXA astronaut Aki Hoshide during an EVA on Nov. 1, 2012, where he and Suni Williams worked to troubleshoot problems with an ammonia leak outside the ISS. Credit: NASA

The time Williams, Hoshide and Malenchenko were on board saw the October arrival the first official commercial spacecraft, SpaceX’s Dragon. Williams and Hoshide also carried out two spacewalks, with Williams now holding the record for total spacewalk time by a female at 50 hours and 40 minutes over seven career spacewalks. Malenchenko is a space veteran with several Soyuz flights, a flight on the Space Shuttle and three stints on the ISS.

Here’s the scene as Williams, Hoshide and Malenchenko say goodbye and close the hatches between the ISS and Soyuz:

Watch: Ultimate Mars Challenge

The PBS special “Ultimate Mars Challenge” that aired this week in the US is now available on YouTube. The production crew did a great job capturing the challenges of putting this mission together, and included scenes from building and testing the rover here on Earth to the nail-biting landing to even including some of the most recent images and discoveries from the mission.

Note: if the video above doesn’t play in your country, try going to the PBS NOVA website and watching it there. You can read more information about the episode here. As we mentioned previously, some of the mosaics and panoramas put together by Universe Today writer Ken Kremer, along with his imaging team partner Marco Di Lorenzo, were used in the PBS show. Congrats to Ken and Marco! Below is one of their images that was used:

Curiosity looks back to her rover tracks and the foothills of Mount Sharp and the eroded rim of Gale Crater in the distant horizon on Sol 24 (Aug. 30, 2012). This panorama is featured on PBS NOVA Ultimate Mars Challenge’ documentary premiering on Nov. 14. The colorized mosaic was stitched together from Navcam images. Credit: NASA / JPL-Caltech / Ken Kremer / Marco Di Lorenzo

HUGE New Gale Crater Panoramas from Curiosity

The image above is a gorgeous view of the Curiosity rover’s surroundings in Gale Crater. However, it is just a sliver of an entire gigantic panorama put together by imaging wizard Stuart Atkinson. It’s made from 34 different images as Curiosity took in a full view of its environs. You can see the full panorama at Stu’s Gale Gazette website, where you can click on it to enlarge it, and as Stu says, “then take a good long look at the beautiful hills forming the rim of the crater. Just magnificent, aren’t they?”

Sure are. Stu told me via email that all this view is missing are “some sand ships hissing over the distant plain, glinting and flashing gold, sapphire and emerald in the sunlight, and a line of sword-swinging Tharks rushing towards the rover!”

Ah, I love Stu’s Barsoomian imagination…

Another imaging wizard from UnmannedSpaceflight.com, James Canvin, is also working on a Gigapan of some of the latest images and at last count has put together 371 images into one huge panorama! The Gigapan technology allows you to pan around and zoom in to see incredible details. Check it out.

UT writer Ken Kremer is also working on some new panoramas, along with his imaging partner Marco Di Lorenzo. Congrats are in order to Ken and Marco for the images, mosaics and panoramas they put together from the MSL mission being used in the PBS NOVA special presentation that aired this week, Ultimate Mars Challenge. The show is now available to watch online: on Universe Today here, or at the PBS website here. There is additional information about the show here.

Astrophoto: Angel of the North Gets a Halo

Halo (Comets and Starry Sky Edition). Credit: Peter Greig (St1nkyPete on Flickr)

What a stunning shot! It took much of the night, but astrophotographer Peter Greig has now given this angel a halo, in the form of star trails. The Angel of the North is a gigantic sculpture located in Gateshead, England. It is a 200 ton steel sculpture of an angel/being with airplane wings that measures 20 meters (66 feet) in height, with wings measuring 54 meters (177 ft) across — making it as tall as 4 double-decker London buses with a wingspan as big as a jumbo jet. The only mystery is, who is sitting at this angel’s feet?

The sculpture was designed by Antony Gormley and was completed in 1998. You can find out more about it here.

Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.

Giant Spiders on Mars!

Eek, spiders! All right, so it’s not actually little green arachnids we’re talking about here, but they are definitely spidery features. Called araneiform terrain, these clusters of radially-branching cracks in Mars’ south polar surface are the result of the progressing spring season, when warmer temperatures thaw subsurface CO2 ice.

As dry ice below the surface warms it can sublimate rapidly and burst through the frozen ground above, creating long cracks. If the material below is dark it can be carried upwards by the escaping gas, staining the surface.

Each dark splotch is around 100 meters wide.

This image was acquired by the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter on September 26, from a distance of 262 km (163.8 miles). See the full-size scan here, and check out more recent HiRISE images in the November PDS release here.

Credit: NASA/JPL/University of Arizona

Are Dust Devils Whirling Around the Curiosity Rover?

In this latest update from the MSL team, Ashwin Vasavada, the Deputy Project Scientist, explains how Curiosity has been monitoring the winds and radiation levels in Gale Crater. Curiosity has also been looking for dust devils — the small dust storms that have been seen by other spacecraft as they whirl around Mars. While Curiosity hasn’t been able to ‘see’ them by taking images directly, other instruments indicate dust devils may be whirling right over the rover.

The team said that during the first 12 weeks after Curiosity landed in Gale Crater, they have analyzed data from more than 20 atmospheric events with at least one characteristic of a whirlwind recorded by the Rover Environmental Monitoring Station (REMS) instrument. Those characteristics can include a brief dip in air pressure, a change in wind direction, a change in wind speed, a rise in air temperature or a dip in ultraviolet light reaching the rover. Two of the events included all five characteristics.

Vasavada said that the winds blow from all directions where the rover sits, in between the central mound of Gale Crater (Aeolis Mons/Mt. Sharp) and the rim of the crater, which makes it an area ripe for dust devils.

Vasavada also points out that the Spirit and Opportunity rovers were able to capture dust devils in their own vicinity, which was an exciting accomplishment. Curiosity’s MastCams can take 720p (1280×720 pixels) high-definition video at a rate of about 10 frames per second, so if the team was ever lucky enough to capture a dust devil in action, it would be our best-ever view of a dust devil on the surface of Mars, and would be tremendously exciting.

Here’s a huge dust devil captured from orbit by the HiRISE camera on the Mars Reconnaissance Orbiter:

A Martian dust devil roughly 12 miles (20 kilometers) high was captured winding its way along the Amazonis Planitia region of Northern Mars on March 14, 2012 by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter. Despite its height, the plume is little more than three-quarters of a football field wide (70 yards, or 70 meters). Image credit: NASA/JPL-Caltech/UA

2012 Leonid Meteor Shower Peaks This Weekend

Early Leonids captured on Nov. 14, 2012 in Ohio. Credit: John Chumack

The annual Leonid Meteor Shower has already begun, according to astrophotographer John Chumack in Ohio, who said he captured a dozen or so via his night sky video cameras earlier this week. But the peak for the Leonids this year is expected to be this weekend, and the best viewing should be during the hours before dawn on November 17, according to the editors of StarDate magazine at the University of Texas at Austin McDonald Observatory

Every year about this time Earth passes through the debris field left by Comet Tempel-Tuttle. The tiny grains of dust enter Earth’s atmosphere and burn up, sometimes leaving glowing dust trails, which we call meteors.

Graphic via StarDate magazine of the Leonid meteor shower.

If you wait until the hours before dawn this weekend, the Moon will be below the horizon, so its light will not interfere with seeing meteors. Astronomers says that with clear skies, viewers can expect to see about 15 to 20 meteors per hour, though the shower has proved highly variable in recent years.

Though the meteors will appear to originate from the constellation Leo, which will be in the eastern sky in the early morning hours, the meteors can be seen in all parts of the sky.

If you capture any images of the meteor shower, share them with Universe Today by uploading them on our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.

Here’s another look at John Chumack’s early Leonids.

Hunting for High Life: What Lives in Earth’s Stratosphere?

The Moon photographed through the layers of the atmosphere from the ISS in December 2003 (NASA/JSC)

What lives at the edge of space? Other than high-flying jet aircraft pilots (and the occasional daredevil skydiver) you wouldn’t expect to find many living things over 10 kilometers up — yet this is exactly where one NASA researcher is hunting for evidence of life.

Earth’s stratosphere is not a place you’d typically think of when considering hospitable environments. High, dry, and cold, the stratosphere is the layer just above where most weather occurs, extending from about 10 km to 50 km (6 to 31 miles) above Earth’s surface. Temperatures in the lowest layers average -56 C (-68 F) with jet stream winds blowing at a steady 100 mph. Atmospheric density is less than 10% that found at sea level and oxygen is found in the form of ozone, which shields life on the surface from harmful UV radiation but leaves anything above 32 km openly exposed.

Sounds like a great place to look for life, right? Biologist David Smith of the University of Washington thinks so… he and his team have found “microbes from every major domain” traveling within upper-atmospheric winds.

Smith, principal investigator with Kennedy Space Center’s Microorganisms in the Stratosphere (MIST) project, is working to take a census of life tens of thousands of feet above the ground. Using high-altitude weather balloons and samples gathered from Mt. Bachelor Observatory in central Oregon, Smith aims to find out what kinds of microbes are found high in the atmosphere, how many there are and where they may have come from.

“Life surviving at high altitudes challenges our notion of the biosphere boundary.”

– David Smith, Biologist, University of Washington in Seattle

Although reports of microorganisms existing as high as 77 km have been around since the 1930s, Smith doubts the validity of some of the old data… the microbes could have been brought up by the research vehicles themselves.

“Almost no controls for sterilization are reported in the papers,” he said.

But while some researchers have suggested that the microbes could have come from outer space, Smith thinks they are terrestrial in origin. Most of the microbes discovered so far are bacterial spores — extremely hardy organisms that can form a protective shell around themselves and thus survive the low temperatures, dry conditions and high levels of radiation found in the stratosphere. Dust storms or hurricanes could presumably deliver the bacteria into the atmosphere where they form spores and are transported across the globe.

If they land in a suitable environment they have the ability to reanimate themselves, continuing to survive and multiply.

Although collecting these high-flying organisms is difficult, Smith is confident that this research will show how such basic life can travel long distances and survive even the harshest environments — not only on Earth but possibly on other worlds as well, such as the dessicated soil of  Mars.

“We still have no idea where to draw the altitude boundary of the biosphere,” said Smith. This research will “address how long life can potentially remain in the stratosphere and what sorts of mutations it may inherit while aloft.”

Read more on Michael Schirber’s article for Astrobiology Magazine here, and watch David Smith’s seminar “The High Life: Airborne Microbes on the Edge of Space” held May 2012 at the University of Washington below:

Inset images – Top: layers of the atmosphere, via the Smithsonian/NMNH. Bottom: Scanning electron microscope image of atmospheric bacterial spores collected from Mt. Bachelor Observatory (NASA/KSC)

Now Even Further: Ancient Galaxy is Latest Candidate for Most Distant

It seems that every few months or so comes a new discovery of a new “most distant galaxy ever found.” It’s not really a surprise that new benchmarks are reached with such an amazing frequency as our telescopes get better and astronomers refine their techniques for observing faraway and ancient objects. This latest “most distant” is pretty interesting in that it was found by combining observations from two space telescopes – Hubble and Spitzer – as well as using massive galaxy clusters as gravitational lenses to magnify the distant galaxy behind them. It’s also extremely small and may not even be a fully developed galaxy at the time we are seeing it.

While this galaxy, named MACS0647-JD, appears as a diminutive blob in the new images, astronomers say it offers a peek back into a time when the universe was just 3 percent of its present age of 13.7 billion years. This newly discovered galaxy was observed 420 million years after the Big Bang, and its light has traveled 13.3 billion years to reach Earth.

“This object may be one of many building blocks of a galaxy,” said Dan Coe of the Space Telescope Science Institute, lead author of a new paper on the observations. “Over the next 13 billion years, it may have dozens, hundreds, or even thousands of merging events with other galaxies and galaxy fragments.”

The discovery comes from the Cluster Lensing And Supernova Survey with Hubble (CLASH), a program that combines the power of space telescopes with the natural zoom of gravitational lensing to reveal distant galaxies in the early Universe. Observations with Spitzer’s infrared eyes allowed for confirmation of this object.

The light from MACS0647-JD was magnified by a massive galaxy cluster named MACS J0647+7015, and without the cluster’s magnification powers, astronomers would not have seen the remote galaxy. Because of gravitational lensing, the CLASH research team was able to observe three magnified images of MACS0647-JD with the Hubble telescope. The cluster’s gravity boosted the light from the faraway galaxy, making the images appear about eight, seven, and two times brighter than they otherwise would that enabled astronomers to detect the galaxy more efficiently and with greater confidence.

“This cluster does what no manmade telescope can do,” said Marc Postman, also from STScI. “Without the magnification, it would require a Herculean effort to observe this galaxy.”

MACS0647-JD is just a fraction of the size of our Milky Way galaxy, and is so small it may not even be a fully formed galaxy. Data show the galaxy is less than 600 light-years wide. Based on observations of somewhat closer galaxies, astronomers estimate that a typical galaxy of a similar age should be about 2,000 light-years wide. For comparison, the Large Magellanic Cloud, a dwarf galaxy companion to the Milky Way, is 14,000 light-years wide. Our Milky Way is 150,000 light-years across.

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The galaxy was observed with 17 filters, spanning near-ultraviolet to near-infrared wavelengths, using Hubble’s Wide Field Camera 3 (WFC3) and Advanced Camera for Surveys (ACS). Coe discovered the galaxy in February while poring over a catalogue of thousands of gravitationally lensed objects found in Hubble observations of 17 clusters in the CLASH survey. But the galaxy appeared only in the two reddest filters.

“So either MACS0647-JD is a very red object, only shining at red wavelengths, or it is extremely distant and its light has been ‘redshifted’ to these wavelengths, or some combination of the two,” Coe said. “We considered this full range of possibilities.”

The CLASH team identified multiple images of eight galaxies lensed by the galaxy cluster. Their positions allowed the team to produce a map of the cluster’s mass, which is primarily composed of dark matter. Dark matter is an invisible form of matter that makes up the bulk of the universe’s mass. “It’s like a big puzzle,” said Coe. “We have to arrange the mass in the cluster so that it deflects the light of each galaxy to the positions observed.” The team’s analysis revealed that the cluster’s mass distribution produced three lensed images of MACS0647-JD at the positions and relative brightness observed in the Hubble image.

Coe and his collaborators spent months systematically ruling out these other alternative explanations for the object’s identity, including red stars, brown dwarfs, and red (old or dusty) galaxies at intermediate distances from Earth. They concluded that a very distant galaxy was the correct explanation.

Redshift is a consequence of the expansion of space over cosmic time. Astronomers study the distant universe in near-infrared light because the expansion of space stretches ultraviolet and visible light from galaxies into infrared wavelengths. Coe estimates MACS0647-JD has a redshift of 11, the highest yet observed.

Images of the galaxy at longer wavelengths obtained with the Spitzer Space Telescope played a key role in the analysis. If the object were intrinsically red, it would appear bright in the Spitzer images. Instead, the galaxy barely was detected, if at all, indicating its great distance. The research team plans to use Spitzer to obtain deeper observations of the galaxy, which should yield confident detections as well as estimates of the object’s age and dust content.

MACS0647-JD galaxy, however, may be too far away for any current telescope to confirm the distance based on spectroscopy, which spreads out an object’s light into thousands of colors. Nevertheless, Coe is confident the fledgling galaxy is the new distance champion based on its unique colors and the research team’s extensive analysis. “All three of the lensed galaxy images match fairly well and are in positions you would expect for a galaxy at that remote distance when you look at the predictions from our best lens models for this cluster,” Coe said.

The new distance champion is the second remote galaxy uncovered in the CLASH survey, a multi-wavelength census of 25 hefty galaxy clusters with Hubble’s ACS and WFC3. Earlier this year, the CLASH team announced the discovery of a galaxy that existed when the universe was 490 million years old, 70 million years later than the new record-breaking galaxy. So far, the survey has completed observations for 20 of the 25 clusters.

The team hopes to use Hubble to search for more dwarf galaxies at these early epochs. If these infant galaxies are numerous, then they could have provided the energy to burn off the fog of hydrogen that blanketed the universe, a process called re-ionization. Re-ionization ultimately made the universe transparent to light.

Read the team’s paper (pdf).

Sources: HubbleSite, ESA Hubble