New Horizons LOng Range Reconnaissance Imager (LORRI) composite image showing the detection of Pluto’s largest moon, Charon, cleanly separated from Pluto itself. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)
The New Horizons spacecraft is still about 880 million kilometers (550 million miles) from Pluto, but on July 1 and 3, 2013, the spacecraft’s LOng Range Reconnaissance Imager (LORRI) was able to detect not only Pluto, but its largest moon, Charon, visible and cleanly separated from Pluto itself. Charon orbits about 19,000 kilometers (12,000 miles) away from Pluto, and seen from New Horizons, that’s only about 0.01 degrees away.
“The image itself might not look very impressive to the untrained eye, but compared to the discovery images of Charon from Earth, these ‘discovery’ images from New Horizons look great!” said New Horizons Project Scientist Hal Weaver. “We’re very excited to see Pluto and Charon as separate objects for the first time from New Horizons.”
The frame on the left in the grouping of images above is an average of six different LORRI images, each taken with an exposure time of 0.1 second. The frame to the right is the same composite image but with Pluto and Charon circled; Pluto is the brighter object near the center and Charon is the fainter object near its 11 o’clock position. The circles also denote the predicted locations of the objects, showing that Charon is where the team expects it to be, relative to Pluto. No other Pluto system objects are seen in these images.
These images are just a hint of what’s to come when New Horizons gets closer to the Pluto system. On July 14, 2015, the spacecraft is scheduled to pass just 12,500 kilometers (7,750 miles) above Pluto’s surface, where LORRI will be able to spot features about the size of a football field.
“We’re excited to have our first pixel on Charon,” said New Horizons Principal Investigator Alan Stern, “but two years from now, near closest approach, we’ll have almost a million pixels on Charon –and I expect we’ll be about a million times happier too!”
ALMA/Spitzer image of a monster star in the process of forming
Even though it comprises over 99% of the mass of the Solar System (with Jupiter taking up most of the rest) our Sun is, in terms of the entire Milky Way, a fairly average star. There are lots of less massive stars than the Sun out there in the galaxy, as well as some real stellar monsters… and based on new observations from the Atacama Large Millimeter/submillimeter Array, there’s about to be one more.
Early science observations with ALMA have provided astronomers with the best view yet of a monster star in the process of forming within a dark cloud of dust and gas. Located 11,000 light-years away, Spitzer Dark Cloud 335.579-0.292 is a stellar womb containing over 500 times the mass of the Sun — and it’s still growing. Inside this cloud is an embryonic star hungrily feeding on inwardly-flowing material, and when it’s born it’s expected to be at least 100 times the mass of our Sun… a true stellar monster.
The location of SDC 335.579-0.292 in the southern constellation of Norma (ESO, IAU and Sky & Telescope)
The star-forming region is the largest ever found in our galaxy.
“The remarkable observations from ALMA allowed us to get the first really in-depth look at what was going on within this cloud,” said Nicolas Peretto of CEA/AIM Paris-Saclay, France, and Cardiff University, UK. “We wanted to see how monster stars form and grow, and we certainly achieved our aim! One of the sources we have found is an absolute giant — the largest protostellar core ever spotted in the Milky Way.”
SDC 335.579-0.292 had already been identified with NASA’s Spitzer and ESA’s Herschel space telescopes, but it took the unique sensitivity of ALMA to observe in detail both the amount of dust present and the motion of the gas within the dark cloud, revealing the massive embryonic star inside.
“Not only are these stars rare, but their birth is extremely rapid and their childhood is short, so finding such a massive object so early in its evolution is a spectacular result.”
– Team member Gary Fuller, University of Manchester, UK
The image above, a combination of data acquired by both Spitzer and ALMA (see below for separate images) shows tendrils of infalling material flowing toward a bright center where the huge protostar is located. These observations show how such massive stars form — through a steady collapse of the entire cloud, rather than through fragmented clustering.
SDC 335.579-0.292 seen in different wavelengths of light.
“Even though we already believed that the region was a good candidate for being a massive star-forming cloud, we were not expecting to find such a massive embryonic star at its center,” said Peretto. “This object is expected to form a star that is up to 100 times more massive than the Sun. Only about one in ten thousand of all the stars in the Milky Way reach that kind of mass!”
(Although, with at least 200 billion stars in the galaxy, that means there are still 20 million such giants roaming around out there!)
IBEX observations of spectral slope, where red and yellow indicate lower energy particles and green and blue higher energy ones. The central portion (circle) is looking down the heliotail and shows two lower energy “lobes” on the port and starboard sides and high energy regions at higher northern and southern latitudes.
Figure taken from McComas et al. , Astrophysical Journal, 2013.
Our Solar System is moving through interstellar space and scientists have long thought that the “bubble” around our Solar System – called the heliosphere – might have a tail, similar to how a comet has a tail or how other stars have astrospheres. But that has all been conjecture…. until now.
The IBEX spacecraft (Interstellar Boundary Explorer) has now seen the tail and has mapped out its structure. IBEX scientists were surprised to see the tail has twists and turns, with four separate “lobes,” making it appear somewhat like a four-leaf clover. This downwind region of the heliosphere is called the heliotail.
“Scientists have always presumed that the heliosphere had a tail,” said Eric Christian, IBEX mission scientist, speaking during a Google+ Hangout announcing the new findings. “But this is actually the first real data that we have to give us the shape of the tail.”
IBEX measures the neutral particles created by collisions at the solar system’s boundaries. This technique, called energetic neutral atom imaging, relies on the fact that the paths of neutral particles are not affected by the solar magnetic field. Instead, the particles travel in a straight line from collision to IBEX. Consequently, observing where the neutral particles came from describes what is going on in these distant regions.
“By collecting these energetic neutral atoms, IBEX provides maps of the original charged particles,” said David McComas, lead author on the team’s paper and principal investigator for IBEX at Southwest Research Institute. “The structures in the heliotail are invisible to our eyes, but we can use this trick to remotely image the outermost regions of our heliosphere.”
What they found was unexpected, McComas said.
“By very carefully assembling the statistical observations from the first three years of IBEX data we’ve been able to fill in what we couldn’t see before,” McComas said during the Hangout, “and what we found was that the heliotail was a much larger structure with a much more interesting configuration.
What they found was a tail that appears to have a combination of fast and slow moving particles. There are two lobes of slower particles on the sides, with faster particles above and below. The entire structure is twisted from the pushing and pulling of magnetic fields outside the solar system. McComas likened it to a how a beach ball might twist around if it was attached to a bungee cord.
The IBEX scientists speaking during the Hangout today said this new information will help us understand what the Voyager spacecraft may encounter as they reach the edge of our Solar System.
“IBEX and Voyager are incredibly complimentary missions,” said Christian. “I’ve often said that IBEX is like an MRI, where it can take an image to understand the big picture of what is going on, where the Voyagers are like biopsies, where we can see what is going on in the local area.”
This was the first time a NASA used a Google+ Hangout to broadcast a press briefing. You can watch the full Hangout below:
You can read David McComas’ blog post on the new findings here, and NASA’s press release here.
A thick green arc of aurora settled in for the night last night. It was about 5 degrees thick and some 10 degrees high. A faint but colorful diffuse aurora glowed above it. All photos taken with a 16-35 mm lens at f/2.8 and 30-second time exposure. Credit: Bob King
A burst of energetic particles from the Sun called a coronal mass ejection peppered Earth’s magnetic field yesterday afternoon sparking a modest but beautiful all-night display of the aurora borealis. Another light show may be in the offing tonight for skywatchers living in the northern U.S., Canada and northern Europe.
Around 1 a.m. the arc became more active, sending up occasional rays that lasted from about a minute before fading away and being replaced by another. Credit: Bob King
Pale green fingers of light splayed across the northern sky at twilight’s end came as a surprise. NOAA space weather forecasters had predicted little activity. These soon faded but a thick, fuzzy arc persisted throughout the night. It arched from horizon to horizon across the northern sky like a pallid, monochromatic rainbow. Such arcs are common. Often the aurora never gets past this stage and simmers quietly or even fades away during the night.
Not this one. Around local midnight (1 a.m. CDT) here in Duluth, Minn. small bright spots and a series of tall, faint rays punctuated the arc and over the span of a half-hour completely reshaped it into loopy rayed arcs resembling a crown.
I wasn’t alone when the northern lights peaked about 1:20-2 a.m. At upper left you’ll see the trails of a couple of fireflies. Credit: Bob King
To the eye, the brightest parts of the aurora appeared green, but the taffy-stretched rays were colorless. The camera’s sensitivity coupled with a 30-second time exposure revealed striking pinks and hints of blue. Both pink and green colors are caused by the emission of light from oxygen atoms.
An especially beautiful ray sticks up above the arc. Shorter exposures coupled with shorter shutter speeds are the best way to capture fine details of a northern lights display. Credit: Bob King
Bombarded by high-speed solar wind electrons and protons, they get jazzed into higher energy states. When the atoms return to rest, each spits out a photon of green or red light. All those tiny flashes add up. Multiplied by the billions of atoms that exist even in the rarefied air at the aurora’s typical 60-150 mile (100-250 km) altitude and you get heavenly eye candy.
When we see an auroral arc – and associated rays – we really seeing a small section of the much larger, permanent aurora called the auroral oval. The northern oval is centered over the geomagnetic north pole located in northern Canada. Credit: NASA
I started watching the northern lights at 11 from home then took a drive to darker skies. Even at dawn’s 3 a.m. start, the green arc held its own shot through with rays that occasionally towered halfway up the northern sky. While this display wasn’t a grand spectacle like some auroras, it possessed a certain majesty the same way a long, slow movement concludes a great symphony.
Chances for more of the same continues through tonight and possibly into tomorrow, so keep a watch on the northern sky before you hit the hay tonight. If you see something green and glowing it you might be in for a treat.
In another installment, I’ll share tips on how best to see the northern lights and share several excellent tools you can use for predicting when they might occur.
The Milky Way and airglow seen in the Dark Sky Alqueva Reserve in Portugal. Credit and copyright: Miguel Claro.
Look closely at this beautiful serene view taken by Miguel Claro from Portugal. Not only is it a stunning view of the skies over Lake Alqueva in the Dark Sky Alqueva Reserve in Portugal, but there are also several scientifically interesting features here. Of course, visible is the arc of the Milky Way, filled with colors and light. Seen here is the most central region of the Milky Way, located near the constellations of Scorpio and Sagittarius, where you might recognize many deep sky objects like the Lagoon Nebula (M8) and the Trifid Nebula (M20).
The “glow” seen here is not the aurora borealis, but instead it is airglow (atmospheric chemiluminescence), which is a photochemical reaction that occurs high in the atmosphere when various atoms get excited from the ultraviolet radiation from the Sun. Miguel explained via email that the yellow light is from emissions from sodium atoms in a layer at 92 km, and above it, is green light from oxygen atoms in a layer 90-100 km high. This emission layer is clearly visible from earth orbit, which we’ve seen in many images and videos taken from the ISS.
An annotated version of the Milky Way and airglow seen in the Dark Sky Alqueva Reserve in Portugal. Credit and copyright: Miguel Claro.
“Reflected in the peaceful lake and due to the polarization effect of water, we could clearly see the entire constellation of Scorpius with the real color of each star naturally saturated,” Miguel said via email, “due to this polarization and blurred effect, caused by the slowly movement of water during the long exposure. The orange color of the Red Supergiant Antares could be easily distinguished from the blue color of the Subgiant star, Shaula, in the end of tail.”
Miguel used a Canon 60Da – ISO 1600; 35mm lens at f/2; Exp. 15 secs. Mosaic of 23 images, taken on June 15, at 02:35 AM.
Artist's Concept of NASA’s Mars 2020 Rover envisions a basic structure that capitalizes on re-using the design and engineering work done for the NASA rover Curiosity, which landed on Mars in 2012, but with new science instruments for accomplishing different science objectives with the 2020 mission. Credit: NASA/JPL-Caltech
NASA’s next Mars rover set for liftoff in 2020 should focus on three primary objectives; seeking signs of past life, collecting a cache of carefully chosen samples for eventual return to Earth and developing technologies that will help enable future human missions to the Red Planet some two decades from now.
The 2020 goals were laid out publicly today (July 9) by a panel of scientists on the ‘Science Definition Team’ and charged by NASA with defining the key science objectives for the new mission.
The science objectives and how to accomplish them are outlined in considerable detail in a newly issued 154 page report handed over to the space agency and discussed at today’s NASA briefing for the media.
Looking for signs of ancient life and preserved biosignatures on Mars at a place that was once habitable is the top priority of the 2020 mission. The SDT report states that the landing site should be chosen specifically to “explore the geology of a once habitable site.”
“We need a highly mobile rover that can make ‘in situ’ science measurements,” said Jack Mustard, chairman of the Science Definition Team and a professor at the Geological Sciences at Brown University in Providence, R.I., at the briefing.
“The rover would use its own instruments on Mars for visual, mineralogical and chemical analysis down to a microscopic scale to identify candidate features that may have been formed by past life,” states the SDT report.
“We can’t do this now with Curiosity,” explained Mustard. “We need higher resolution.”
Looking for ‘extant’ life, that is life surviving on Mars today, would be a by-product of the search for organic molecules and preserved biosignatures of life – past or present.
The Mars 2020 ‘Science Definition Team’ (SDT) is comprised of 19 scientists and engineers from academia and industry. They were appointed by NASA in January 2013 to thoroughly and quickly evaluate a wide range of options to accomplish the highest priority planetary science objectives and achieve President Obama’s challenge to send humans to Mars in the 2030s.
Retrieving soil and rock samples from Mars for analysis back on Earth by research teams worldwide using all the most advanced analytical instruments available to humankind with unprecedented capability has been the ‘Holy Grail’ of Mars exploration for several decades.
But the enormous cost and technical complexity of a Mars Sample Return (MSR) mission has caused it to be repeatedly postponed.
Creating a Returnable Cache of Martian Samples is a major objective for NASA’s Mars 2020 rover. This prototype show hardware to cache samples of cores drilled from Martian rocks for possible future return to Earth. The 2020 rover would be to collect and package a carefully selected set of up to 31 samples in a cache that could be returned to Earth by a later mission. The capabilities of laboratories on Earth for detailed examination of cores drilled from Martian rocks would far exceed the capabilities of any set of instruments that could feasibly be flown to Mars. The exact hardware design for the 2020 mission is yet to be determined. For scale, the diameter of the core sample shown in the image is 0.4 inch (1 centimeter). Credit: NASA/JPL-Caltech
The 2020 rover will be designed to make real progress on sample return for the first time. It will be capable of coring into rocks and storing 31 highly compelling Martian samples for return by a follow on mission to the Red Planet.
“But the timing on actually returning those samples to Earth is yet to be determined,” said John Grunsfeld, NASA’s associate administrator for science in Washington.
Everything NASA does is budget driven and the fiscal climate is rather gloomy right now.
“Crafting the science and exploration goals is a crucial milestone in preparing for our next major Mars mission,” said John Grunsfeld, NASA’s associate administrator for science in Washington, in a statement.
Work on the new rover must begin soon in order to achieve the mandatory 2020 launch deadline. Launch opportunities to Mars only open every 26 months and delays could balloon the costs by several hundred million dollars.
“The objectives determined by NASA with the input from this team will become the basis later this year for soliciting proposals to provide instruments to be part of the science payload on this exciting step in Mars exploration,” adds Grunsfeld.
“The 2020 rover will take a major step in ‘seeking signs of life” said Jim Green, director of NASA’s Planetary Science Division in Washington, at the briefing. “NASA will issue a call for science instruments this fall.”
The new mission would build upon the demonstrated science accomplishments of earlier missions like Curiosity, Spirit, Opportunity and Phoenix while vastly advancing the capabilities of the robots research instruments.
“Here’s the bottom line. Questions drive science,” explained Lindy Elkins-Tanton, SDT member and director of the Carnegie Institution for Science’s Department of Terrestrial Magnetism, Washington.
“We should be seeking to answer the very biggest questions. And one of the very biggest questions for all of humankind is – ‘Are we alone?’ And that is the question we’re hoping to make really big advances with on with this Mars 2020 mission.”
Grunsfeld explained that NASA has budgeted “for a mission cost of $1.5 Billion plus the cost of the launcher.”
The 2020 rover chassis, with some modifications, will be based on the blueprints of the highly successful Curiosity rover to keep down the cost and minimize risks. But the science instruments will be completely new and updated.
NASA’s 1 ton Curiosity rover touched down nearly a year ago and has already discovered that the Red Planet has the chemical ingredients and environmental conditions for a habitable zone that could have supported living Martian microbes.
The next logical step is to look for the ancient signs of life that would be preserved in the rock record on Mars.
NASA’s 2020 Mars rover would be based on the Curiosity rover which touched down inside Gale Crater on Aug. 6, 2012 and discovered a habitable zone here. This photomosic shows NASA’s Curiosity departing Glenelg work site area at last for Mount Sharp- her main science destination, seen at top left. Note the wheel tracks on the Red Planet’s surface. The mosaic of navcam camera images was stitched from photos taken on July 4, 2013 (Sol 324). Credit: NASA/JPL-Caltech/Ken Kremer (kenkremer.com)/Marco Di Lorenzo
Those of us with long tresses have wondered, how do you wash that floating mass of hair in space? Astronaut and Expedition 36 crewmember Karen Nyberg provides a how-to video direct from the International Space Station. Obviously, Nyberg’s crewmate Luca Parmitano doesn’t have to go through this process.
But wash your hair today, have drinking water or coffee tomorrow!
NASA Orion spacecraft blasts off atop 1st Space Launch System rocket in 2017 - attached to European provided service module – on an enhanced m mission to Deep Space where an asteroid could be relocated as early as 2021. Credit: NASA
NASA Orion spacecraft blasts off atop 1st Space Launch System rocket in 2017 – attached to European provided service module – on an ambitious mission to explore Deep Space some 40,000 miles beyond the Moon, where an asteroid could be relocated as early as 2021. Credit: NASA Story updated with further details[/caption]
NASA managers have announced a bold new plan to significantly alter and upgrade the goals and complexity of the 1st mission of the integrated Orion/Space Launch System (SLS) human exploration architecture – planned for blastoff in late 2017.
The ambitious first flight, called Exploration Mission 1 (EM-1), would be targeted to send an unpiloted Orion spacecraft to a point more than 40,000 miles (70,000 kilometers) beyond the Moon as a forerunner supporting NASA’s new Asteroid Redirect Initiative – recently approved by the Obama Administration.
The EM-1 flight will now serve as an elaborate harbinger to NASA’s likewise enhanced EM-2 mission, which would dispatch a crew of astronauts for up close investigation of a small Near Earth Asteroid relocated to the Moon’s vicinity.
Orion crew module separates from Space Launch System (SLS) upper stage. Credit: NASA
Until recently NASA’s plan had been to launch the first crewed Orion atop the 2nd SLS rocket in 2021 to a high orbit around the moon on the EM-2 mission, said NASA Associate Administrator Lori Garver in an prior interview with me at the Kennedy Space Center.
Concept of NASA spacecraft with Asteroid capture mechanism deployed to redirect a small space rock to a stable lunar orbit for later study by astronauts aboard Orion crew capsule. Credit: NASA.
The enhanced EM-1 flight would involve launching an unmanned Orion, fully integrated with the Block 1 SLS to a Deep Retrograde Orbit (DRO) near the moon, a stable orbit in the Earth-moon system where an asteroid could be moved to as early as 2021.
Orion’s mission duration would be nearly tripled to 25 days from the original 10 days.
“The EM-1 mission with include approximately nine days outbound, three to six days in deep retrograde orbit and nine days back,” Brandi Dean, NASA Johnson Space Center spokeswoman told Universe Today exclusively.
The proposed much more technologically difficult EM-1 mission would allow for an exceptionally more vigorous work out and evaluation of the design of all flight systems for both Orion and SLS before risking a flight with humans aboard.
Asteroid Capture in Progress
A slew of additional thruster firings would exercise the engines to change orbital parameters outbound, around the moon and inbound for reentry.
The current Deep Retrograde Orbit (DRO) plan includes several thruster firings from the Orion service module, including a powered lunar flyby, an insertion at DRO, an extraction maneuver from the DRO and a powered flyby on return to Earth.
Orion would be outfitted with sensors to collect a wide variety of measurements to evaluate its operation in the harsh space environment.
“EM-1 will have a compliment of both operational flight instrumentation and development flight instrumentation. This instrumentation suite gives us the ability to measure many attributes of system functionality and performance, including thermal, stress, displacement, acceleration, pressure and radiation,” Dean told me.
The EM-1 flight has many years of planning and development ahead and further revisions prior to the 2017 liftoff are likely.
“Final flight test objectives and the exact set of instrumentation required to meet those objectives is currently under development,” Dean explained.
Orion is NASA’s next generation manned space vehicle following the retirement of NASA’s trio of Space Shuttles in 2011.
The SLS launcher will be the most powerful and capable rocket ever built by humans – exceeding the liftoff thrust of the Apollo era Moon landing booster, the mighty Saturn V.
“We sent Apollo around the moon before we landed on it and tested the space shuttle’s landing performance before it ever returned from space.” said Dan Dumbacher, NASA’s deputy associate administrator for exploration systems development, in a statement.
“We’ve always planned for EM-1 to serve as the first test of SLS and Orion together and as a critical step in preparing for crewed flights. This change still gives us that opportunity and also gives us a chance to test operations planning ahead of our mission to a relocated asteroid.”
Both Orion and SLS are under active and accelerating development by NASA and its industrial partners.
The 1st Orion capsule is slated to blast off on the unpiloted EFT-1 test flight in September 2014 atop a Delta IV Heavy rocket on a two orbit test flight to an altitude of 3,600 miles above Earth’s surface.
Technicians work on mockups of the Orion crew capsule, Service Module and 6 ton Launch Abort System (LAS) to simulate critical assembly techniques inside the Vehicle Assembly Building (VAB) at NASA’s Kennedy Space Center (KSC) in Florida for the EFT-1 mission due to liftoff in September 2014. Credit: Ken Kremer/kenkremer.com
It will then reenter Earth’s atmosphere at speeds of about 20,000 MPH (11 km/sec) and endure temperatures of 4,000 degrees Fahrenheit in a critical test designed to evaluate the performance of Orion’s heatshield and numerous spacecraft systems.
Orion EFT-1 is already under construction at the Kennedy Space Center (KSC) by prime contractor Lockheed Martin – read my earlier story here.
Integration and stacking tests with Orion’s emergency Launch Abort System are also in progress at KSC – details here.
NASA says the SLS is also in the midst of a extensive review process called the Preliminary Design Review (PDR) to ensure that all launch vehicle components and systems will achieve the specified performance targets and be completed in time to meet the 2017 launch date. The PDR will be completed later this summer.
NASA’s goal with Orion/SLS is to send humans to the Moon and other Deep Space destinations like Asteroids and Mars for the first time in over forty years since the final manned lunar landing by Apollo 17 back in 1972.
NASA Headquarters will make a final decision on upgrading the EM-1 mission after extensive technical reviews this summer.
Astronaut Karen Nyberg helps Chris Cassidy (left) and Luca Parmitano suit up for their spacewalk on July 9, 2013. Credit: NASA
Want a “you are there” view of today’s EVA that took place outside the International Space Station? Take a look at this great video of astronaut Chris Cassidy getting a ride on the station’s Canadarm-2 to make repairs and prepare for a new Russian laboratory. There are several great “over the shoulder” views during this short highlight video.
During their 6-hour and 7-minute spacewalk, Cassidy of NASA and Luca Parmitano of the European Space Agency worked on replacing a failed communications receiver, relocating grapple bars for future spacewalks and stringing cables for the when the Russian laboratory module arrives later this year.
The Ku-band communications receiver replaces one that failed last December. There was already a redundant backup system now in use, and this new one will become the backup.
The new Russian lab, called Nauka, will replace the Pirs airlock. It is scheduled to launch on a Proton rocket booster late this year, although the flight could be delayed a bit until early next year as because of assembly delays in Russia.
This spacewalk was the first of two in as many weeks for the duo. They will again venture outside the Quest airlock on July 16 for more upgrades and repairs. This was Parmitano’s first spacewalk, and he has now become the first Italian astronaut to walk in space. Old pro Cassidy has now been on five spacewalks, and this was the 170th spacewalk in support of space station assembly and maintenance.
An artist's conception of how common exoplanets are throughout the Milky Way Galaxy. Image Credit: Wikipedia
A new study suggests that the number of habitable exoplanets within the Milky Way alone may reach 60 billion.
Previous research performed by a team at Harvard University suggested that there is one Earth-sized planet in the habitable zone of each red dwarf star. But researchers at the University of Chicago and Northwestern University have now extended the habitable zone and doubled this estimate.
The research team, lead by Dr. Jun Yang considered one more variable in their calculations: cloud cover. Most exoplanets are tidally locked to their host stars – one hemisphere continually faces the star, while one continuously faces away. These tidally locked planets have a permanent dayside and a permanent nightside.
One would expect the temperature gradient between the two to be very high, as the dayside is continuously receiving stellar flux, while the nightside is always in darkness. Computer simulations that take into account cloud cover show that this is not the case.
The dayside is covered by clouds, which lead to a “stabilizing cloud feedback” on climate. It has a higher cloud albedo (more light is reflected off the clouds) and a lower greenhouse effect. The presence of clouds actually causes the dayside to be much cooler than expected.
“Tidally locked planets have low enough surface temperatures to be habitable,” explains Jang in his recently published paper. Cloud cover is so effective it even extends the habitable zone to twice the stellar flux. Planets twice as close to their host star are still cool enough to be habitable.
But these new statistics do not apply to just a few stars. Red dwarfs “represent about ¾ of the stars in the galaxy, so it applies to a huge number of planets,” Dr. Abbot, co-author on the paper, told Universe Today. It doubles the number of planets previously thought habitable throughout the entire galaxy.
Not only is the habitable zone around red dwarfs much larger, red dwarfs also live for much longer periods of time. In fact, the Universe is not old enough for any of these long-living stars to have died yet. This gives life the amount of time necessary to form. After all, it took human beings 4.5 billions years to appear on Earth.
Another study we reported on earlier also revised and extrapolated the habitable zone around red dwarf stars.
Future observations will verify this model by measuring the cloud temperatures. On the dayside, we will only be able to see the high cool clouds. A planet resembling this model will therefore look very cold on the dayside. In fact, “a planet that does show the cloud feedback will look hotter on the nightside than the dayside,” explains Abbot.
This effect will be testable with the James Webb Space Telescope. All in all, the Milky Way is likely to be teeming with life.
