While exoplanets make the news on an almost daily basis, one of the biggest announcements occurred in 2012 when astronomers claimed the discovery of an Earth-like planet circling our nearest neighbor, Alpha Centauri B, a mere 4.3 light-years away. That’s almost close enough to touch.
Of course such a discovery has led to a heated debate over the last three years. While most astronomers remain skeptical of this planet’s presence and astronomers continue to study this system, computer simulations from 2008 actually showed the possibility of 11 Earth-like planets in the habitable zone of Alpha Centauri B.
Now, recent research suggests that five of these computer-simulated planets have a high potential for photosynthetic life.
The 2008 study calculated the likely number of planets around Alpha Centauri B by assuming an initial protoplanetary disk populated with 400 – 900 rocks, or protoplanets, roughly the size of the Moon. They then tracked the disk over the course of 200 million years through n-body simulations — models of how objects gravitationally interact with one another over time — in order to determine the total number of planets that would form from the disk.
While the number and type of exoplanets depended heavily on the initial conditions given to the protoplanetary disk, the eight computer simulations predicted the formation of 21 planets, 11 of which resided within the habitable zone of the star.
A second team of astronomers, led by Dr. Antolin Gonzalez of the Universidad Central de Las Villas in Cuba, took these computer simulations one step further by assessing the likelihood these planets are habitable or even contain photosynthetic life.
The team used multiple measures that asses the potential for life. The Earth Similarity index “is a multi-parameter first assessment of Earth-likeness for extrasolar planets,” Dr. Gonzalez told Universe Today. It predicts (on a scale from zero to one with zero meaning no similarity and one being identical to Earth) how Earth-like a planet is based on its surface temperature, escape velocity, mean radius and bulk density.
Planets with an Earth Similar index from 0.8 – 1 are considered capable of hosting life similar to Earth’s. As an example Mars has an Earth Similar index in the range of 0.6 – 0.8. It is thus too low to support life today.
However, the Earth Similarity index alone is not an objective measure of habitability, Gonzalez said. It assumes the Earth is the only planet capable of supporting life. The team also relied on the P model for biological productivity, which takes into account the planet’s surface temperature and the amount of carbon dioxide present.
At this point in time “there is no way to predict, at least approximately, the partial pressure of carbon dioxide with the known data, or the variations from a planet to another,” Gonzalez said. Instead “we assumed a constant partial pressure of carbon dioxide for all planets simplifying the model to a function of temperature.”
Gonzalez’s team found that of the 11 computer-simulated planets in the habitable zone, five planets are prone for photosynthetic life. Their Earth Similarity index values are 0.92, 0.93, 0.87, 0.91 and 0.86. If we take into account their corresponding P model values we find that two of them have better conditions than Earth for life.
According to this highly theoretical paper: if there are planets circling our nearest neighbor, they’re likely to be teeming with life. It’s important to note that while these indexes may prove to be very valuable years down the road (when we have a handful of Earth-like planets to study), we are currently only looking for life as we know it.
The paper has been published in the Cuban journal: Revista Cubana de Fisica and is available for download here. For more information on Alpha Centauri Bb please read a paper available here published in the Astrophysical Journal.
The Soyuz-U rocket sits ready for launch at the baikonur Cosmodrome earlier today. Credit: The Russian Space Agency.
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The first launch of February 2014 worldwide is about to light up the night skies over the Baikonur Cosmodrome in Kazakhstan, with the launch of a Soyuz-U rocket carrying the uncrewed Progress M-22M spacecraft to the ISS. You can watch the launch live here, as well as the “fast-track” docking just 5 hours and 58 minutes later.
Progress will be carrying 2.8 tons of fuel, oxygen, supplies and experiments to the International Space Station. This will be the 54th Progress flight to the International Space Station since the first Progress launch to the station in 2000.
The launch is set to occur at 16:23:33 Universal Time or 11:23:33 AM EST. NASA TV will go live with the launch at 11:00 AM EST/16:00 UT, and TV Tsenki will also broadcast video from the pad just prior, though the broadcast frequently its sans audio.
Progress is also on a four orbit “fast-track” launch headed to the International Space Station. Tune in to NASA TV at 5:00 PM EST/22:00 UT later today, and you’ll be able to catch the docking of the Progress spacecraft to the Pirs module of the ISS as well. Docking is set to occur at 5:25 PM EST/22:25 UT over the North Atlantic Ocean.
Fun fact: Neil Armstrong still holds the record for the fastest journey from liftoff to docking at 5 hours and 33 minutes during Gemini 8 way back in 1966.
Update: ISS Astros indeed report during the live broadcast of the launch of Progress M-22M on NASA TV today of catching sight of the first stage of the Soyuz-U at liftoff… we’ll post any pics if and when they surface.
Progress M-20M undocked from the same Pirs compartment earlier this week on Monday in order to make way for the arrival of Progress M-22M. Progress M-20M is still in orbit, and is slated for a fiery destructive reentry on February 11th over the South Pacific. The long span between undocking and reentry for Progress M-20M allows for experiments on the spacecraft’s attitude control system to be carried out by ground controllers.
…and LIFTOFF of the Soyuz-U rocket from the Baikonur Cosmodrome with Progress M-22M! Credit: NASA TV.
This also marks the start of a busy 2014 season at the International Space Station. On March 1st, SpaceX continues its contract to resupply the station with the launch of a Falcon 9 rocket with its fifth Dragon capsule making its third operational delivery to the station on CRS-3. Then later in March on the 12th, Expedition 38 crewmembers Oleg Kotov, Sergey Ryazansky, and NASA astronaut Michael Hopkins will return to Earth aboard Soyuz TMA-10M. The next crewed launch headed to the International Space Station are Expedition 39 cosmonauts Alexander Skvortsov, Oleg Artemyev, and NASA astronaut Steve Swanson launching from Baikonur on March 26th on Soyuz TMA-12M.
Progress M-22M is ultimately slated to undock from the Pirs module of the International Space Station on April 7th for a destructive reentry over the South Pacific. Three additional SpaceX launches utilizing Dragon capsules and two more launches of Orbital Science’s Cygnus cargo spacecraft will be conducted in 2014, as well as visits by the European Space Agency’s ATV-5 Georges Lemaitre in June and JAXA’s HTV-5 in July.
And another launch from the Baikonur Cosmodrome is coming right up on Valentine’s Day, February 14th, with the liftoff of an International Launch Services Proton rocket carrying the Turksat 4A satellite. The launch will be carried live via the ILS website and is slated for 21:09 UT/4:09 PM EST.
And though these are all standard resupply missions to the International Space Station, spaceflight is anything but routine. Avid trackers of live launches will remember the Progress M-12M spacecraft that was lost shortly after launch back in August 2011. To date, Progress M-12M was the only supply craft that failed to reach the International Space Station. Progress M-12M impacted in the Choisk Region of Russia’s Altai Republic in the Far East. The RD-0110 engine began to experience a flight anomaly just over five minutes after launch, causing the flight computer to execute a termination of thrust. Progress M-12M was the first loss of a Progress spacecraft since the start of the program in 1978. Ironically, Progress M-12M carried among its cargo manifest 10 paintings made by the son of Russian artist Alesandr Shilov said to be for “the psychological support of the crew…” There’s also a small cottage industry in Siberia east of Russian launch sites in salvaging rocket parts and boosters for scrap metal as they plummet from the sky.
Tonight’s passage of Progress M-20M and the International Space Station over the US SE and the Caribbean region. Created by the author using Orbitron.
It’s also possible to spot these spacecraft from your backyard as they arrive and depart from the International Space Station. We caught sight of Progress M-20M just last night, passing very near the waxing crescent Moon. Progress was about magnitude +1 when directly overhead, and was about 9 minutes ahead of the International Space Station. We’ve seen the Dragon, HTV, ATV spacecraft, as well as the U.S. Space Shuttle shortly after undocking from the International Space Station when it was in service. In fact, there’s a series of good passes of the ISS at dusk over the next few evenings for the southeastern United States, including a pass at ~6:58 PM EST tonight. Progress M-20M should be about 20 minutes ahead of the station at this point, assuming, of course, it hasn’t maneuvered in its orbit as a part of ongoing thruster control experiments.
We’ll be checking those final orbital corrections just prior to the pass tonight, as well as tracking the launch and docking of Progress M-22M. Follow us on Twitter (@Astroguyz) for further updates.
Be sure to catch all the action at Baikonur and in low Earth orbit today, both online and overhead!
Itokawa, a peanut-shaped asteroid that has different densities in its small body. Credit: ESO/JAXA
From directly inferring the inside of an asteroid for the first time, astronomers have discovered these space rocks can have strange variations in density. The observations of Itokawa — which you may remember from the Japanese Hayabusa mission that landed on the asteroid in 2005 — not only teach us more about how asteroids came to be, but could help protect Earth against stray space rocks in the future, the researchers said.
“This is the first time we have ever been able to to determine what it is like inside an asteroid,” stated Stephen Lowry, a University of Kent scientist who led the research. “We can see that Itokawa has a highly varied structure; this finding is a significant step forward in our understanding of rocky bodies in the solar system.”
It’s not clear why Itokawa has such different densities at opposite sides of its peanut shape; perhaps it was two asteroids that rubbed up against each other and merged. At just shy of six American football fields long, the space rock has density varying from 1.75 to 2.85 grams per cubic centimetre. This precise measurement came courtesy of the European Southern Observatory’s New Technology Telescope in Chile.
The telescope calculated the speed and speed changes of Itokawa’s spin and combined that information with data on how sunlight can affect the spin rate. Asteroids are generally tiny and irregularly shaped sorts of bodies, which means the effect of heat on the body is not evenly distributed. That small difference makes the asteroid’s spin rate change.
This heat effect (more properly called the Yarkovsky-O’Keefe-Radzievskii-Paddack effect) is slowly making Itokawa’s spin rate go faster, at a rate of 0.045 seconds every Earth year. This change, previously unexpected by scientists, is only possible if the peanut bulges have different densities, the scientists said.
“Finding that asteroids don’t have homogeneous interiors has far-reaching implications, particularly for models of binary asteroid formation,” added Lowry. “It could also help with work on reducing the danger of asteroid collisions with Earth, or with plans for future trips to these rocky bodies.”
Depiction of NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) observatory as it approaches lunar orbit.Credit: NASA Ames/Dana Berry
Depiction of NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE) observatory as it approaches lunar orbit.Credit: NASA Ames/Dana Berry
LADEE will now orbit far lower than ever before – details below![/caption]
LADEE, NASA’s latest lunar orbiter, is getting a new lease on life and will live a little longer to study the mysteries of the body’s tenuous atmosphere, or exosphere, and make surprising new discoveries while hugging Earth’s nearest neighbor even tighter than ever before, the team told Universe Today.
NASA has announced that the Lunar Atmosphere and Dust Environment Explorer (LADEE) mission will be granted a month long extension since the residual rocket fuel is more than anticipated due to the expertise of LADEE’s navigation engineers.
This is great news because it means LADEE’s three research instruments will collect a big bonus of science measurements about the pristine lunar atmosphere and dust during an additional 28 days in an ultra tight low orbit skimming around the Moon.
And the extension news follows closely on the heels of LADEE being photographed in lunar orbit for the first time by a powerful camera aboard NASA’s five year old Lunar Reconnaissance Orbiter (LRO), her orbital NASA sister – detailed here.
This dissolve animation compares the LRO image (geometrically corrected) of LADEE captured on Jan 14, 2014 with a computer-generated and labeled image of LADEE . LRO and LADEE are both NASA science spacecraft currently in orbit around the Moon. Credit: NASA/Goddard/Arizona State University
LADEE is currently flying around the moon’s equator at altitudes ranging barely eight to 37 miles (12-60 kilometers) above the surface which crosses over from lunar day to lunar night approximately every two hours.
During the extended mission lasting an additional full lunar cycle, LADEE will fly even lower to within a few miles (km) thereby allowing scientists an exceptional vantage point to unravel the mysteries of the moon’s atmosphere.
Just how low will LADEE fly?
I asked Rick Elphic, LADEE project scientist at NASA Ames Research Center, Moffett Field, Calif.
“We will be taking LADEE from its nominal 20 to 50 kilometer periapsis right down to the treetops — we want to get data from 5 kilometers or even less!” Elphic told me.
“So far we’ve been keeping a healthy margin for spacecraft safety, but after the nominal mission is completed, we will relax those requirements in the interest of new science.”
With the measurements collected so far the science team has already established a baseline of data for the tenuous lunar atmosphere, or exosphere, and dust impacts, says NASA.
Therefore the LADEE team is free to fly the spacecraft much lower than ever before.
And why even go to lower altitudes? I asked Elphic.
Basically because the team hopes to see changes in the particle density and composition.
“The density depends on the species. For instance, argon-40 is heavier than neon-20, and has a lower scale height. That means we should see a big increase in argon compared to neon.”
“And we may see the heavier species for the first time at these really low altitudes.”
“It’s remotely possible we’ll see krypton, for instance.”
“But the real boon will be in the dust measurements.”
“LDEX (The Lunar Dust Experiment) will be measuring dust densities very close to the surface, and we will see if something new shows up. Each time we’ve dropped our orbit down to lower altitudes, we’ve been surprised by new things,” Elphic told Universe Today.
The Neutral Mass Spectrometer (NMS) instrument will measure the identity and abundances of the exospheres constituents, such as argon, neon and krypton.
LADEE Science Instrument locations
With the extension, LADEE is expected to continue capturing data in orbit until about April 21, 2014, depending on the usage of the declining on board fuel to feed its maneuvering thrusters.
“LADEE is investigating the moons tenuous exosphere, trace outgases like the sodium halo and lofted dust at the terminator,” Jim Green, Planetary Science Division Director at NASA HQ, told me earlier in an exclusive interview.
“The spacecraft has a mass spectrometer to identify the gases, a physical dust detector and an imager to look at scattered light from the dust. These processes also occur at asteroids.”
The Lunar Dust Experiment (LDEX) recorded dust impacts as soon as its cover opened, says NASA and is also seeing occasional bursts of dust impacts caused by meteoroid showers, such as the Geminids.
By studying the raised lunar dust, scientists also hope to solve a 40 year old mystery – Why did the Apollo astronauts and early unmanned landers see a glow of rays and streamers at the moon’s horizon stretching high into the lunar sky.
The science mission duration had initially been planned to last approximately 100 days and finish with a final impact on the Moon on about March 24th.
And the team had told me before launch that an extension was rather unlikely since the spacecraft would be flying in such a very low science orbit of about 50 kilometers altitude above the moon that it will require considerable fuel to maintain.
“LADEE is limited by the amount of onboard fuel required to maintain orbit,” Doug Voss, launch manager, Wallops, told me.
So what accounts for the extension?
Basically it’s because of the expert navigation by NASA’s engineers and the Orbital Sciences Minotaur V rocket and upper stages following the spectacular night time LADEE blastoff from NASA Wallops, VA, on Sept. 6, 2013 and subsequent insertion into lunar orbit.
“The launch vehicle performance and orbit capture burns using LADEE’s onboard engines were extremely accurate, so the spacecraft had significant propellant remaining to enable extra science,” said Butler Hine, LADEE project manager at NASA’s Ames where the mission was designed, built, tested, in a NASA statement.
“This extension represents a tremendous increase in the amount of science data returned from the mission.”
Launch of NASA’s LADEE lunar orbiter on Friday night Sept. 6, at 11:27 p.m. EDT on the maiden flight of the Minotaur V rocket from NASA Wallops, Virginia, viewing site 2 miles away. Antares rocket launch pad at left. Credit: Ken Kremer/kenkremer.com
“LADEE launched with 134.5 kilograms of fuel. After the third lunar orbit insertion burn (LOI-3), 80% of our fuel had been consumed,” said Dawn McIntosh, LADEE deputy project manager at NASA Ames Research Center, in an exclusive interview with Universe Today.
“Additional orbit-lowering maneuvers with the orbital control system (OCS) and reaction control system (RCS) of approximately 40 seconds were used to get LADEE into the science orbit.
And LADEE’s orbit capture was accomplished amidst the ridiculous US government shutdown with a skeleton crew.
The spacecraft finally entered its planned two hour science orbit around the moon’s equator on Nov. 20.
So LADEE’s orbital lifetime depends entirely on the remaining quantity of rocket fuel.
“LADEE has about 20 kg of propellant remaining today,” Butler Hine told Universe Today.
The 844 pound (383 kg) robot explorer is the size of a couch and was assembled at NASA’s Ames Research Center, Moffett Field, Calif., and is a cooperative project with NASA Goddard Spaceflight Center in Maryland.
Full scale model of NASA’s LADEE lunar orbiter on display at the free visitor center at NASA’s Wallops Flight Facility in Virginia. Credit: Ken Kremer/kenkremer.com
The $280 million probe is built on a revolutionary ‘modular common spacecraft bus’, or body, that could dramatically cut the cost of exploring space and also be utilized on space probes to explore a wide variety of inviting targets in the solar system.
“LADEE is the first in a new class of interplanetary exploration missions,” NASA Ames Center Director Pete Worden told me in an interview. “It will study the pristine moon to study significant questions.”
“This is probably our last best chance to study the pristine Moon before there is a lot of human activity there changing things.”
To date LADEE has traveled over 1 million miles and in excess of 1200 equatorial orbits around the Moon.
LADEE is also searching for any changes caused to the exosphere and dust by the landing of China’s maiden Chang’e-3 lander and Yutu moon rover in December 2013.
Stay tuned here for Ken’s continuing LADEE, Chang’e-3, Orion, Orbital Sciences, SpaceX, commercial space, Mars rover and more news.
Paul Mahaffy, LADEE Neutral Mass Spectrometer instrument, principal investigator, and Ken Kremer/Universe Today discuss LADEE science at NASA Wallops Flight Facility, VA. Credit: Ken Kremer/kenkremer.com
Diagram of Kepler-413b's unusual orbit around red and orange dwarf stars. Its orbit "wobbles" or precesses around the stars every 11 years. Credit: NASA, ESA, and A. Feild (STScI)
We’re lucky to live on a planet where it’s predictably warmer in the summer and colder in the winter in many regions, at least within a certain range. On Kepler-413b, it’s a world where you’d have to check the forecast more frequently, because its axis swings by a wild 30 degrees every 11 years. On Earth, by comparison, it takes 26,000 years to tilt by a somewhat lesser amount (23.5 degrees).
The exoplanet, which is 2,300 light-years away in the constellation Cygnus, orbits two dwarf stars — an orange one and a red one — every 66 days. While it would be fun to imagine a weather forecast on this planet, in reality it’s likely too hot for life (it’s close to its parent stars) and also huge, at 65 Earth-masses or a “super-Neptune.”
What’s even weirder is how hard it was to characterize the planet. Normally, astronomers spot these worlds either by watching them go across the face of their parent star(s), or by the gravitational wobbles they induce in those stars. The orbit, however, is tilted 2.5 degrees to the stars, which makes the transits far more unpredictable. It took several years of Kepler space telescope data to find a pattern.
“What we see in the Kepler data over 1,500 days is three transits in the first 180 days (one transit every 66 days), then we had 800 days with no transits at all,” stated Veselin Kostov, the principal investigator on the observation. “After that, we saw five more transits in a row,” added Kostov, who works both with the the Space Telescope Science Institute and Johns Hopkins University in Baltimore, Md.
It will be an astounding six years until the next transit happens in 2020, partly because of that wobble and partly because the stars have small diameters and aren’t exactly “edge-on” to our view from Earth. As for why this planet is behaving the way it does, no one is sure. Maybe other planets are messing with the orbit, or a third star is doing the same thing.
The next major question, the astronomers added, is if there are other planets out there like this that we just can’t see because of the gap between transit periods.
You can read more about this finding in The Astrophysical Journal (a Jan. 29 publication that doesn’t appear to be on the website yet) or in preprint version on Arxiv.
Sunspot region 1967 is so big it easily popped into view through a "cloud filter" Sunday afternoon Feb. 2. The group is visible with the naked eye properly shielded by a safe solar filter. Details: 350mm lens at f/11, ISO 200 and 1/2000". Credit: Bob King
What a crazy sunspot cycle. Weeks go by with only a few tiny spots freckling the sun, then all at once a monster group big enough to swallow 10 Earths rounds the eastern limb and we’re back in business. I’m happy to report we’ve got another behemoth snapping and crackling with M-class (moderately strong) flares – Active Region 1967, a hunk-a-hunk of burnin’ funk that rounded the solar limb a week ago.
NOAA weather forecasters predict an 80% chance of continued M-flares and a 50% chance over the next 3 days for considerably more powerful X-class flares. This sunspot group has a delta classification magnetic field, the Facebook equivalent of “It’s complicated”.
Sunspots are made of a dark umbra and lighter penumbra. Very tiny spots with no penumbrae are called pores. A close up of the sun’s photosphere shows a finely granulated texture. Granules are cells of hot gas about the size of Texas that rise from below, cool and sink. Each lasts from 8 to 20 minutes. Credit: NASA
Sunspots have two parts: a dark core (or cores) called an umbra surrounded by a paler skirt of magnetic energy, the penumbra. They can look impressive like this one, but it’s hard to call a sunspot a “thing”. It’s really more of a locale on the sun’s bright white photosphere where bundles of powerful magnetic energy bob up from below the surface and insulate a region of the sun’s fiery hydrogen gas from the rest of the flaming globe.
We’re talking insulate as in staying cool. While the photosphere cooks at around 11,000 degrees Fahrenheit, sunspots are some 3,000 degrees cooler. That’s why they appear dark to the eye. If you could rip them away from the sun and see them alone against the sky, they’d be too bright to look at safely.
Close up of AR 1967 photographed by the Solar Dynamics Observatory at 8:45 p.m. CST Feb. 4, 2014. Credit: NASA
A delta-class spot group has umbrae of both polarities, north and south, corralled within the penumbra. Like bringing opposite poles of a two magnets so close they snap together, something similar can happen inside delta-class groups. Only instead of a snap, a titanic thermonuclear explosion called a flare goes kaboom.The biggest flares release the equivalent of a billion hydrogen bombs.
The huge sunspot group 1967 straddles the center of the solar disk on Feb. 3, 2014. The smaller group, AR 1968, lies to its north. Through a filtered telescope, AR 1967 is packed with fascinating details. Photo made with a 6-inch reflector, Baader solar filter, 1/2000 exposure, ISO 400. Credit: John Chumack
We thank our lucky stars for Earth’s iron heart, which generates our protective magnetic shield, and the 93 million miles that separate us from the sun. AR 1967 has paraded right in front of our noses as it rotated with the sun. Yesterday it squarely faced the Earth – a good thing when it comes to the particle blasts that fire up the northern lights. Let’s hope it showers us with a magnetic goodness in the coming days. I really miss seeing the aurora. You too? NOAA space weather forecasters are calling for a 25% chance of auroras in Arctic latitudes overnight Feb. 4-5. We at mid-latitudes will try to be patient.
U.S. president Barack Obama (foreground, left) with SpaceX CEO Elon Musk during a 2010 tour at the Kennedy Space Center in Florida. (Credit: Chuck Kennedy)
SpaceX CEO Elon Musk is a huge fan of Mars exploration and Mars colonies, and in a new interview he says a launch system to send people to the Red Planet could be available in 10 to 12 years. Requirements: it has to be big, and it has to be launched frequently to send millions of people and tons of cargo spaceward.
“We need to develop a much larger vehicle, which would be a sort of Mars colonial transport system, and this would be, we’re talking about rockets on a bigger scale than has ever been done before. It will make the Apollo moon rocket look small,” said Musk in a recent CBS interview, referring to the 363-foot (110-meter) behemoth that was the Saturn V.
In the short term, Musk said he is focused on making a crew transportation system that will reduce NASA’s reliance on Soyuz vehicles to bring astronauts into space (a situation that arose in 2011 after the agency retired the shuttle.) SpaceX is one of three companies funded by NASA to develop a spacecraft able to launch people (with the other two being Boeing and Sierra Nevada.)
Musk said SpaceX’s Dragon should be ready to do that in a couple of years. Meanwhile, there are abort tests to perform and other steps this year to get the spacecraft ready for that milestone.
Artists impression of a Super-Earth, a class of planet that has many times the mass of Earth, but less than a Uranus or Neptune-sized planet. Credit: NASA/Ames/JPL-Caltech
Alien planets that are slightly bigger than Earth could be more life-friendly than exoplanets closer to our own size, a new study implies. These so-called “super-Earths” that are about two to three times that of our own planet could be “superhabitable” — implying that our own planet is a rare bird indeed when it comes to being good for life.
Bigger rocky planets would have a host of advantages, argue McMaster University’s Rene Heller and Weber State University’s John Armstrong in a paper recently published in Astrobiology. Among them: These worlds would have tectonic activity that takes longer to happen, meaning that the conditions would be more stable for life. Also, a bigger mass implies it’s easier to hang on to a thick atmosphere and to have “enhanced magnetic shielding” to hold a planet’s own against solar flares.
“Our argumentation can be understood as a refutation of the Rare Earth hypothesis. Ward and Brownlee (2000) claimed that the emergence of life required an extremely unlikely interplay of conditions on Earth, and they concluded that complex life would be a very unlikely phenomenon in the Universe,” stated the authors in their paper “Superhabitable Worlds.”
Information about Alpha Centauri Bb. Information about Alpha Centauri Bb. Credit: Planetary Habitability Laboratory/University of Puerto Rico/Arecibo
“While we agree that the occurrence of another truly Earth-like planet is trivially impossible, we hold that this argument does not constrain the emergence of other inhabited planets. We argue here in the opposite direction and claim that Earth could turn out to be a marginally habitable world. In our view, a variety of processes exists that can make environmental conditions on a planet or moon more benign to life than is the case on Earth.”
As a start, the scientists suggest looking at the Alpha Centauri system, where researchers in 2012 discovered a planet close to Earth’s size that is likely not habitable because it orbits so close to its sun.
The star system, however, is about the right age and has low enough radiation to allow life to occur on a planet or moon that “evolved similarly as it did on Earth”, providing the planet or moon “had the chance to collect water from comets and planetesimals beyond the snowline.” Further, it’s just four light-years from Earth, making it a good target for telescopic observations.
European Space Agency astronaut Alexander Gerst (left, in mask) and NASA astronaut Reid Wiseman during fire drill training at NASA's Johnson Space Center in Houston. Credit: NASA
Facing a fire in space? It’s among the most catastrophic situations possible, according to NASA, so the agency spends a lot of time thinking of what to do. Here’s what you do with NASA training: Don a mask, grab an emergency book, and head quickly but calmly to the nearest control post to plot an attack.
This is presumably what is happening in the recent picture above, where Alexander Gerst (from the European Space Agency, on the left) and NASA’s Reid Wiseman are doing a fire drill on the ground.
Astronauts practice emergency procedures so often that their first instinct is to go to the procedures, Gerst said in a previous Universe Today interview. “They sink in and become a memorized response or a natural reaction,” he said in August. And in his case, Gerst has training from a previous career that would come in handy if a fire broke out on the International Space Station.
Gerst was a volunteer firefighter when he was attending school, and although Expedition 40/41 this year will be his first spaceflight, he’s well-used to extreme environments: he also has done science in Antarctica, where researchers are essentially responsible for themselves for months at a time.
NASA strives to make the fire training as real as possible to keep astronauts on their toes, including creative combinations of smoke machines. Gerst said the agency won’t go to extremes, however: “We don’t light our modules on fire,” he said.
Check out more about emergency training in this past Universe Today article, which also explains the difference between fighting a fire on the space station and dealing with one in a Soyuz spacecraft. Gerst and Reid (both rookie astronauts) and Russian astronaut Maxim Suraev (who was on Expeditions 21 and 22) are supposed to head into space in May.
At left, Photograph of Jupiter's enormous Great Red Spot in 1879 from Agnes Clerk's Book " A History of Astronomy in the 19th Century".
Watch out! One day it may just go away. Jupiter’s most celebrated atmospheric beauty mark, the Great Red Spot (GRS), has been shrinking for years. When I was a kid in the ’60s peering through my Edmund 6-inch reflector, not only was the Spot decidedly red, but it was extremely easy to see. Back then it really did span three Earths. Not anymore.
Drawing of Jupiter made on Nov. 1, 1880 by French artist and astronomer Etienne Trouvelot showing transiting moon shadows and a much larger Great Red Spot.
In the 1880s the GRS resembled a huge blimp gliding high above white crystalline clouds of ammonia and spanned 40,000 km (25, 000 miles) across. You couldn’t miss it even in those small brass refractors that were the standard amateur observing gear back in the day. Nearly one hundred years later in 1979, the Spot’s north-south extent has remained virtually unchanged, but it’s girth had shrunk to 25,000 km (15,535 miles) or just shy of two Earth diameters. Recent work done by expert astrophotographer Damian Peach using the WINJUPOS program to precisely measure the GRS in high resolution photos over the past 10 years indicates a continued steady shrinkage:
2003 Feb – 18,420km (11,445 miles)
2005 Apr – 18,000km (11,184)
2010 Sep – 17,624km (10,951)
2013 Jan – 16,954km (10,534)
2013 Sep – 15,894km (9,876)
2013 Dec – 15,302km (9,508) = 1.2 Earth diameters
Voyager 1 Jupiter time lapse animation, a reprocessed high-resolution view. Enlarge to full screen to see the GRS rotation best. Credit: NASA / JPL / Bjorn Jonsson / Ian Regan
If these figures stand up to professional scrutiny, it make one wonder how long the spot will continue to be a planetary highlight. It also helps explain why it’s become rather difficult to see in smaller telescopes in recent years. Yes, it’s been paler than normal and that’s played a big part, but combine pallor with a hundred-plus years of downsizing and it’s no wonder beginning amateur astronomers often struggle to locate the Spot in smaller telescopes . This observing season the Spot has developed a more pronounced red color, but unless you know what to look for, you may miss it entirely unless the local atmospheric seeing is excellent.
Reprocessed view by Bjorn Jonsson of the Great Red Spot made by Voyager 1 in 1979 reveals an incredible wealth of detail. The Spot is a vast, long-lived. hurricane-like storm located between opposing jet streams in Jupiter’s southern hemisphere. Click to enlarge. Credit: NASA/
Not only has the Spot been shrinking, its rotation period has been speeding up. Older references give the period of one rotation at 6 days. John Rogers (British Astronomical Assn.) published a 2012 paper on the evolution of the GRS and discovered that between 2006 to 2012 – the same time as the Spot has been steadily shrinking – its rotation period has spun up to 4 days. As it shrinks, the storm appears to be conserving angular momentum by spinning faster the same way an ice skater spins up when she pulls in her arms.
Drawings by Cassini of what is presumably the Great Red Spot from 1665 to 1677. South is up. In size and shape it greatly resembles the current Red Spot. (From Amedee Guillemin’s “Le Ciel” 1877)
Rogers also estimated a max wind speed of 300 mph, up from about 250 mph in 2006. Despite its smaller girth, this Jovian hurricane’s winds pack more punch than ever. Even more fascinating, the Great Red Spot may have even disappeared altogether from 1713 to 1830 before reappearing in 1831 as a long, pale “hollow”. According to Rogers, no observations or sketches of that era mention it. Surely something so prominent wouldn’t be missed. This begs the question of what happened in 1831. Was the “hollow” the genesis of a brand new Red Spot unrelated to the one first seen by astronomer Giovanni Cassini in 1665? Or was it the resurgence of Cassini’s Spot?
14-frame animation showing the circulation of Jupiter’s atmosphere spans 24 Jovian days, or about 10 Earth days. The passage of time is accelerated by a factor of 600,000. Credit: Voyager 1 / NASA
Clearly, the GRS waxes and wanes but exactly what makes it persist? By all accounts, it should have dissipated after just a few decades in Jupiter’s turbulent environment, but a new model developed by Pedram Hassanzadeh, a postdoctoral fellow at Harvard University, and Philip Marcus, a professor of fluid dynamics at the University of California-Berkeley, may help to explain its longevity. At least three factors appear to be at play:
* Jupiter has no land masses. Once a large storm forms, it can sustain itself for much longer than a hurricane on Earth, which plays itself out soon after making landfall.
* Eat or be eaten: A large vortex or whirlpool like the GRS can merge with and absorb energy from numerous smaller vortices carried along by the jet streams.
* In the Hassanzadeh and Marcus model, as the storm loses energy, it’s rejuvenated by vertical winds that transport hot and cold gases in and out of the Spot, restoring its energy. Their model also predicts radial or converging winds within the Spot that suck air from neighboring jet streams toward its center. The energy gained sustains the GRS.
Feb. 1 photo of Oval BA, a.k.a. Red Spot Jr. It’s the first significant new red spot ever observed on Jupiter and located at longitude 332 degrees (Sys. II) The spot about half the width of the more familiar Great Red Spot. Credit: Christopher GoIf the shrinkage continues, “Great” may soon have to be dropped from the Red Spot’s title. In the meantime, Oval BA (nicknamed Red Spot Jr.) and about half the size of the GRS, waits in the wings. Located along the edge of the South Temperate Belt on the opposite side of the planet from the GRS, Oval BA formed from the merger of three smaller white ovals between 1998 and 2ooo. Will it give the hallowed storm a run for its money? We’ll be watching.
Time-lapse of Jupiter’s atmospheric motions centered on the Great Red Spot photographed by Paolo Porcellana. Each cylindrical/spherical map of the planet is a mosaic of 4-6 pictures made with 11 and 14-inch telescopes.
