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.
Artist's conception of NASA's Space Launch System with Orion crewed deep space capsule. Credit: NASA
NASA’s future in fuels will see less heavy metal. Literally.
The agency just finished testing on a composite propellant tank that holds cryogenics, or super-chilled gases that are commonly used as rocket fuel (such as for the space shuttle). The agency brought the test tank down to -423 degrees Fahrenheit, put it through a few cycles and ramped up the internal pressure.
Composites are lighter material than the traditional metals that are used to hold these gases. NASA is excitedly throwing out descriptors such as “game-changing” when it talks about this, and has some reason to do so: composites are lighter than metals.
The light weight of composite tanks makes them lighter to lift off the ground. This reduces the costs of launch, which in turn reduces the overall cost of a mission. That will make penny-counters at the agency happier as the agency battles for funding dollars in fiscal 2014 and beyond.
The first of these tanks is likely to be used in the upper stage of NASA’s Space Launch System rocket, which is under development right now. That’s the rocket that’s supposed to send the Orion spacecraft (aiming for a 2014 test flight) into space in the latter years of this decade.
“The tank manufacturing process represents a number of industry breakthroughs, including automated fiber placement of oven-cured materials, fiber placement of an all-composite tank wall design that is leak-tight, and a tooling approach that eliminates heavy joints,” stated Dan Rivera, the Boeing cryogenic tank program manager at Marshall.
Boeing and NASA are now working on another composite tank that should be tested at Marshall later in 2013.
This photomosic shows NASA’s Curiosity departing at last for Mount Sharp- her main science destination. Note the wheel tracks on the Red Planet’s surface. The navcam camera images were taken on July 4, 2013 (Sol 324). Credit: NASA/JPL-Caltech/Ken Kremer (kenkremer.com)/Marco Di Lorenzo
NASA’s Curiosity rover has at last begun her epic trek to the layered slopes of mysterious Mount Sharp – the mission’s primary destination which looms supreme inside the Gale Crater landing site.
Scientists expect to discover signatures of the chemical ingredients that potentially are markers for a Martian habitable zone, while climbing up Mount Sharp.
On July 4 (Sol 324), the six wheeled robot started driving away from the Glenelg and Yellowknife Bay areas where she has worked more than half a year investigating the alien terrain and drilling into Martian rocks for the first time in history.
“We have started the long traverse to the base of Mt. Sharp (Aeolis Mons), the long-term goal of the mission!” announced science team member Ken Herkenhoff of the USGS.
So far the NASA rover already driven more than 190 feet (58 meters) over two excursions on July 4 and 7, away from her last science campaign at the Shaler outcrop of cross-bedded, sedimentary outcrops. Another drive is planned today.
Billions of years of Mars geologic history are preserved in the sedimentary layers of Mount Sharp- including the ancient time period when the Red Planet was far wetter and warmer than today, and thus more hospitable to the origin of life.
Billion-Pixel View From Curiosity at Rocknest, Raw Color. This full-circle view combined nearly 900 images taken by NASA’s Curiosity Mars rover, generating a panorama with 1.3 billion pixels in the full-resolution version. The view is centered toward the south, with north at both ends. It shows Curiosity at the “Rocknest” site where the rover scooped up samples of windblown dust and sand. Curiosity used three cameras to take the component images on several different days between Oct. 5 and Nov. 16, 2012. Credit: NASA/JPL-Caltech/MSSS
The huge mountain rises about 3.4 miles (5.5 km) from the center of Gale Crater. Its taller than Mount Ranier in Washington State.
The overland journey could take nearly a year or even longer into 2014 to arrive at the base of Mount Sharp, depending on what the 1 ton behemoth sees along the way.
And the scientists are eager to make as many discoveries as possible.
“The mission is discovery driven,” says John Grotznger of the California Institute of Technology in Pasadena, Calif., who leads NASA’s Curiosity Mars Science Laboratory mission. “We will go to where the science takes us.”
This is a cropped, reduced version of panorama from NASA’s Mars rover Curiosity with 1.3 billion pixels in the full-resolution version see full panorama above. It shows Curiosity at the “Rocknest” site where the rover scooped up samples of windblown dust and sand. Curiosity used three cameras to take the component images on several different days between Oct. 5 and Nov. 16, 2012. Viewers can explore this image with pan and zoom controls at http://mars.nasa.gov/bp1/. Credit: NASA/JPL-Caltech/MSSS
NASA chose Gale Crater as the landing site specifically to dispatch Curiosity to investigate the sedimentary layers of Mount Sharp because in surveys from Mars orbit it exhibited signatures of clay minerals that form in neutral water and that could possibly support the origin and evolution of simple Martian life forms, past or present.
“We have a real desire to get to Mount Sharp because there we see variations in the mineralogy as we go up from the base to higher levels and a change in the record of the environment,” explained Joy Crisp of JPL, Curiosity’s deputy project scientist.
“If we pass something amazing and compelling we might turn around and drive back,” Crisp added.
“The challenge for the science team will be to identify the most important targets along the way, and to study them without delaying drive progress too much,” notes Herkenoff.
Mount Sharp lies about 5 miles (8 kilometers) distant – as the Martian crow flies.
And Curiosity must also pass through a potentially treacherous dune field to get there.
“We are looking for the best path though,” said Curiosity Project Manager Jim Erickson of NASA’s Jet Propulsion Laboratory, Pasadena, Calif. at a recent media briefing.
Fisheye view of Mount Sharp from the hazcam camera on July 6, 2013 (Sol 326). Credit: NASA/JPL-Caltech
11 months ago on Aug. 6 , 2012, Curiosity made an unprecedented pinpoint touchdown inside Gale Crater using the never before used Sky crane descent thrusters.
Long before even arriving at destination Mount Sharp, Curiosity has already successfully accomplished the key science objective of the mission when she discovered that liquid water flowed at this spot on Mars, it possesses the key chemical ingredients required for life and was habitable in the past.
Drill samples from the ‘John Klein’ outcrop at Yellowknife Bay analyzed by Curiosity’s pair of onboard chemistry labs – SAM & Chemin – revealed that this location contains clay minerals required to support microbial life forms.
“We have found a habitable environment [at John Klein] which is so benign and supportive of life that probably if this water was around, and you had been on the planet, you would have been able to drink it,” said Grotzinger.
And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, sign up to be a host. Send an email to the above address.
In our previous episode, week we explored the various ways spacecraft can die. But this week, we explore the spacecraft (and the scientists) who never give up, snatching victory from the jaws of defeat. We’ll look at clever solutions to potential spacecraft catastrophes.
The waxing crescent Moon joins the evening sky early this week. (Photo by author).
The planets are slowly returning into view this month, bashfully peeking out from behind the Sun in the dawn & dusk sky. This month offers a bonanza of photogenic conjunctions, involving the Moon, planets and bright stars.
The action begins tonight on July 8th, as the waxing crescent Moon joins the planet Venus in the dusk sky. The razor thin Moon will be a challenge on Monday night, as it just passed New on the morning of the 8th at 3:14AM EDT/7:14 Universal Time (UT). The record for spotting the thin crescent with the naked eye currently stands at 15 hours and 32 minutes, completed by Stephen O’Meara on May 1990. Binoculars help considerably in this endeavor. Wait until 15 minutes after local sunset, and then begin patiently sweeping the horizon.
Mr. Thierry Legault completed an ultimate photographic challenge earlier today, capturing the Moon at the precise moment of New phase!
The Moon & Venus on the evening of July 9th as seen from latitude 30 degrees north, about 30 minutes after sunset. (Created by the author using Stellarium).
This week marks the start of lunation 1120. The Moon will be much easier to nab for observers worldwide on Tuesday night, July 9th for observers worldwide. The sighting of the waxing crescent Moon will also mark the start of the Muslim month of Ramadan for 2013. Due to the angle of the ecliptic in July, many northern hemisphere observers may not spot the Moon until Wednesday night on July 10th, about 6.7 degrees south west of -4.0 magnitude Venus.
Did you know? There are Guidelines for the Performance of Islamic Rites for Muslims aboard the International Space Station. It’s interesting to note that the timing of the rituals follows the point from which the astronaut originally embarked from the Earth, which is exclusively the Baikonur Cosmodrome in Kazakhstan for the foreseeable future of manned spaceflight.
Malaysia’s first astronaut, Sheikh Muszaphar Shukor observed Ramadan aboard the International Space Station in 2007.
From there, the crescent Moon fattens, meeting up with Saturn and Spica on the evenings of July 15th and 16th. The Moon will actually occult (pass in front of) the bright star Spica on the evening of July 15/16th at ~3:33UT/11:33PM EDT (on the 15th) for observers in Central America and western South America. The rest of us will see a near miss worldwide.
The waxing crescent Moon nearing Spica on the evening of the 15th at 10PM EDT. The Moon reaches 1st Quarter phase on the same evening at 11:18PM EDT. (Created by the author using Starry Night).
This is the 13th in a cycle of 18 occultations of Spica by our Moon spanning 2012-2013. Spica is one of four stars brighter than magnitude +1.4 that lie close enough to the ecliptic to be occulted by our Moon, the others being Antares, Regulus and Aldebaran. Saturn will lie 3 degrees from the Moon on the evening of July 16th.
Can you nab Spica and Saturn near the Moon with binoculars in the daytime around the 15th? It can be done, using the afternoon daytime Moon as a guide. Crystal clear skies (a rarity in the northern hemisphere summertime, I know) and physically blocking the Sun behind a building or hill helps.
The waxing gibbous Moon will also occult +2.8 Alpha Librae for South Africa on July 17th around 17:09UT & +4.4th magnitude Xi Ophiuchi for much of North America on the night of July 19th-20th.
And speaking of Regulus, the brightest star in the constellation Leo lies only a little over a degree (two Full Moon diameters) from Venus only the evenings of July 21st & the 22nd. 77.5 light years distant, Regulus is currently over 100 times fainter at magnitude +1.4. Can you squeeze both into the field of view of your telescope at low power? Venus’s mythical ‘moon’ Neith lives!
Venus can even occult Regulus on rare occasions, as last occurred on July 7th, 1959 and will happen next on October 1st, 2044.
But there’s morning action afoot as well. The planets Mars and Jupiter have emerged from solar conjunction on April 18th and June 19th, 2013 respectively, and can now be seen low in the dawn skies about 30 minutes before sunrise.
Mars and Jupiter in a close conjunction on the morning of July 22nd, about 30 minutes before sunrise as seen from latitude 30 degrees north. (Created by the author using Starry Night).
Mars approaches Jupiter in the dawn until the pair is only 0.79 degrees (about 48 arc minutes) apart on Monday, July 22nd. Mars shines at magnitude +1.6 and shows a tiny 3.9” disk, while Jupiter displays a 32.5” disk shining at magnitude -1.9 on this date. Conjunction occurs at about 7:00 UT/3:00 AM EDT, after which the two will begin to race apart. Mercury is visible beginning its morning apparition over 5 degrees to the lower right of the pair (see above).
Jupiter will reach opposition and reenter the evening sky on January 5th, 2014, while Mars won’t do the same until April 8th of next year. Weird factoid alert: neither Jupiter or Mars reach opposition in 2013! What effect does this have on terrestrial affairs? Absolutely none, well unless you’re a planetary imager/observer…
Mars also reaches its most northern declination of 2013 of 24 degrees in the constellation Gemini on July 16th at 7:00 AM EDT/11:00 UT. Mars can wander as far as declination 27 degrees north, as last happened in 1993.
Finally, are you observing from southern Mexico this week and up for a true challenge? The asteroid 238 Hypatia occults a +7.4 magnitude star from 10:13-10:49 UT on July 10th in the constellation Pisces for up to 29 seconds. This event will be bright enough to watch with binoculars- check out our best prospects for asteroid occultations of stars in 2013 here and here.
Good luck, clear skies, and be sure to post those astro-pics in the Universe Today’s Flickr community!
The belly of space shuttle Atlantis in the new exhibit at the Kennedy Space Center. Credit: Steven Coates
Two years after space shuttle Atlantis launched into space, it’s still looking like it returned from a long journey. It “bears the scars, scorch marks and space dust of its last mission,” writes the Kennedy Space Center Visitors’ Center.
That’s deliberate, though. In late June, visitors to the Orlando-area attraction got the chance to get nose-to-nose with this orbiter in a new exhibit. Atlantis, unlike similar exhibits of other shuttles so far, is perched on a precise 43.21-degree angle to give a view previously afforded only to astronauts.
The $100 million, 90,000-square-foot exhibit also has an International Space Station gallery, a simulated shuttle launch ride, and training simulators for landing, space station docking and moving the robotic Canadarm.
Today (July 8) marked the two-year launch anniversary of STS-135, the last journey of both Atlantis and the shuttle program. Its main goal was to haul a huge load of supplies and spare parts to the space station. The event also generated a NASA Social, which many of the participants (including Universe Today‘s Jason Major) recalled today:
There is almost nothing that could completely destroy the earth.
Follow your instincts and ignore anyone raising alarms about its imminent demise.
Oh sure, there’s a pile of events that could make life more difficult, and a laundry list of things that could wipe out all of humanity. Including: asteroid strikes, rising temperatures, or global plagues
In order to actually destroy the Earth, you would need significantly more energy, and there just happens to be enough, a short 150 million kilometers away: the Sun.
The Sun has been in the main sequence of its life for the last 4.5 billion years, converting hydrogen into helium. For stars this massive, that phase lasts for about 10 billion years, meaning we’re only halfway through.
When the Sun does finally run out of hydrogen to burn, it’ll begin fusing helium into carbon, expanding outward in the process. It will become a cooler, larger, red giant star, consuming the orbits of Mercury and Venus.
Scientists are still unsure if the red giant phase of the Sun will consume the Earth. If it does, the Earth’s story ends there. It’ll get caught up inside the Sun, and spiral inward to its demise.
Death by red giant in 5.5 billion years.
If the Sun doesn’t consume the Earth then we’ll have a long, cold future ahead of us. The Sun will shrink down to a white dwarf and begin cooling down to the background temperature of the Universe. The Earth and the rest of the surviving planets will continue orbiting the dying Sun for potentially trillions of years.
Planet orbiting a dead star. Credit: NASAIf we’re exceedingly lucky, the Sun will get too close to another star, and the gravitational interactions will capture Earth in orbit, giving our planet a second chance for life. If not, the Earth will continue following the dying Sun around and around the Milky Way for an incomprehensible amount of time.
At this point, the main risk to the planet is a collision. Or maybe it’ll spiral inward over vast periods of time to be destroyed by the Sun, or collide with another planet. Or perhaps the entire Solar System will slowly make its way into the supermassive black hole at the center of the Milky Way.
One last possibility. Physicists think that protons – the building blocks of atoms – might eventually decay, becoming smaller particles and pure energy. After an undecillion years – a 1 followed by 36 zeros – half of the Earth will have just melted away into energy.
But if protons don’t decay, the Earth could theoretically last forever.
Sunspot regions 1785 and 1787, with Earth shown to scale. Credit: Guillermo Abramson
Do you feel like you’re in the firing gallery? These sunspots are practically square-on to Earth right now. Although they haven’t shown much sign of erupting, if they did our planet would be right in the line of fire if a flare or stream of solar particles erupted.
These groups (known as 1785 and 1787) are so big that they are easily visible in amateur telescopes. 1785 alone is more than 11 Earth-diameters across, according to SpaceWeather.com! Just make sure you have the proper solar filters in place before you gaze at these dark smudges.
A black-and-white view of the string of sunspots facing Earth right now. Credit: Paul M. Hutchinson
“Sunspots” — so called because they appear as dark smudges on the face of the sun — are areas of intense magnetic activity on the sun (thousands of times stronger than that of Earth’s magnetic field.)
At times, these regions can get so intense that the energy builds up and releases in the form of a flare and/or a coronal mass ejection — a burst of gas and magnetism that hurls solar material away from the sun.
If these flares hit the area of the Earth, a bunch of things can happen. Particles can flow along Earth’s magnetic lines and lead to the creation of aurora, or Northern/Southern lights. (Here’s an aurora that happened in June.) More severe storms can short out satellites or disable power lines.
“Could it be the calm before the storm?” SpaceWeather.com asked on its homepage, before giving forecasts of strong types of flares: “NOAA forecasters estimate a 55% chance of M-flares and a 10% chance of X-flares on July 8.”
We’ll keep our eyes peeled and let you know if something interesting happens. In the meantime, these pictures came from Universe Today readers, and we’d love to see your images, too! Feel free to add your snapshots to our Flickr page.
Update, 2:39 EDT: Among the pictures in our Flickr pool is this new stunner below from Ron Cottrell of Oro Valley, Arizona. “These sunspots are so magnificent that I get striking detail with my small 40mm Hydrogen-alpha telescope,” he wrote us.
A large sunspot group taken in July 2013 with a 40mm Hydrogen-alpha telescope. Credit: Ron Cottrell
This image shows the tiny lunar crescent at the precise moment of the New Moon, in full daylight at 7h14min UTC on July 8 2013. Credit and copyright: Thierry Legault.
It’s always striking to see a tiny sliver of the New Moon. But you’ve probably never seen a sliver this tiny or a Moon this “new” before. This brand new image by astrophotographer extraordinaire Thierry Legault was taken this morning and is the youngest possible lunar crescent, with the “age” of the Moon at this instant being exactly zero — at the precise moment of the New Moon. The image was taken in full daylight at 07:14 UTC on July 8, 2013.
Normally it is just about impossible (and dangerous) to see this, as when the Moon is this “new,” the Moon is between the Earth and the Sun and it is so close to the Sun in our sky that it can’t be seen because of the Sun’s glare. Plus, the New Moon appears as an extremely thin crescent which is barely brighter than the blue sky. But Thierry has designed a special sunshade to prevent sunlight from entering the telescope (see it below).
Thierry says the irregularities and discontinuities seen in the edge of the crescent are caused by the relief at the edge of the lunar disk; i.e. mountains and craters on the Moon. Very cool!
The “New Moon” is defined as the instant when the Moon is at the same ecliptic longitude as the Sun. When we refer to the “age” of the Moon, it is the number of hours (or days) since New Moon.
From Thierry’s shooting site in Elancourt, France (a suburb of Paris), the angular separation between the Moon and the Sun was only 4.4° (nine solar diameters).
“At this very small separation, the crescent is extremely thin (a few arc seconds at maximum) and, above all, it is drowned in the solar glare, the blue sky being about 400 times brighter than the crescent itself in infrared (and probably more than 1000 times in visible light),” Thierry writes on his website. “In order to reduce the glare, the images have been taken in close infrared and a pierced screen, placed just in front of the telescope, prevents the sunlight from entering directly in the telescope.”
Thierry Legault with his special telescope filter for blocking the Sun’s rays. Image courtesy Thierry Legault.
Thierry cautions anyone trying to see this with the naked eye. Basically, don’t try it.
“The very thin crescent of the New Moon cannot be observed visually whatever the instrument (naked eye, binoculars, telescope, etc),” he said. “Moreover, pointing a celestial object that close to the Sun is dangerous for the observer and his equipment if it is not performed under the control of an experienced astronomer and with the proper equipment.”
If you want to keep track of what the Moon will look like each night (or day!), Universe Today has a great app for that, our Phases of the Moon app, available for iOS or Android.
