Credits: NASA/ISAS/DSS/A. Simionescu et al.; inset: NASA/CXC/A. Fabian et al.
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The Japanese Suzaku X-ray telescope has just taken a close look at the Perseus galaxy cluster, and revealed it’s got a bit of a spare tire.
Suzaku explored faint X-ray emission of hot gas across two swaths of the Perseus Galaxy Cluster. The resulting images, which record X-rays with energies between 700 and 7,000 electron volts in a combined exposure of three days, are shown in the two false-color strips above. Bluer colors indicate less intense X-ray emission. The dashed circle is 11.6 million light-years across and marks the so-called virial radius, where cold gas is now entering the cluster. Red circles indicate X-ray sources not associated with the cluster.
The results appear in today’s issue of Science.
The Perseus cluster (03hh 18m +41° 30‘) is the brightest extragalactic source of extended X-rays.
Lead author Aurora Simionescu, an astrophysicist at Stanford, and her colleagues note that until now, most observations of galaxy clusters have focused on their bright interiors. The Suzaku telescope was able to peer more closely at the outskirts of the Perseus cluster. The resulting census of baryonic matter (protons and neutrons of gas and metals) compared to dark matter offers some surprising observations.
It turns out the fraction of baryonic matter to dark matter at Perseus’s center was consistent with measurements for the universe as a whole, but the baryonic fraction unexpectedly exceeds the universal average on the cluster’s outskirts.
“The apparent baryon fraction exceeds the cosmic mean at larger radii, suggesting a clumpy distribution of the gas, which is important for understanding the ongoing growth of clusters from the surrounding cosmic web,” the authors write in the new paper.
Artist's impression of the Cygnus-X1 binary. Credit: NASA / Honeywell Max-Q Digital Group / Dana Berry
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Using the IBIS telescope onboard the European Space Agency’s INTEGRAL satellite, researchers have reported the first measurements of polarization from a black hole binary system, which comprises a black hole and a normal star orbiting around a common center of mass.
The new observations reveal that the chaotic region is threaded by magnetic fields, and represent the first time magnetic fields have been identified so close to a black hole. Most importantly, Integral shows they are highly structured magnetic fields that are forming an escape tunnel for hot matter that would otherwise plunge into the black hole within milliseconds.
Credit: ESA, courtesy of Philippe Laurent
Philippe Laurent is a researcher with the Institute for Research into the Fundamental Laws of the Universe (IRFU), of the CEA in France. He is lead author on the paper, which appears today in Science Express.
Laurent and his colleagues detected polarized gamma-ray photons coming from Cygnus X-1 (19h 58m 21.6756s +35° 12′ 05.775″), a well-known black hole X-ray binary system in the constellation Cygnus. They suggest the polarized emission is originating from a jet of relativistic particles in close proximity to the black hole.
The graph above refers to the team’s results: “whereas the low energy photons seem not to be polarized (the inset line at the left is merely flat), the higher energy ones are strongly polarized (the inset line in the right seems to be sinusoidal), and thus should related to the jet,” Laurent wrote in an email.
The authors reveal more detail through the paper: “Spectral modeling of the data reveals two emission mechanisms: The 250-400 keV data are consistent with emission dominated by Compton scattering on thermal electrons and are weakly polarized,” they write. “The second spectral component seen in the 400keV-2MeV band is by contrast strongly polarized, revealing that the MeV emission is probably related to the jet first detected in the radio band.”
Their evidence points to the black hole’s magnetic field being strong enough to tear away particles from the black hole’s gravitational clutches and funnel them outwards, creating jets of matter that shoot into space, according to an ESA press release. The particles in the jets are being drawn into spiral trajectories as they climb the magnetic field to freedom and this is affecting a property of their gamma-ray light known as polarization.
A gamma ray, like ordinary light, is a kind of wave, and the orientation of the wave is known as its polarization. When a fast particle spirals in a magnetic field it produces a kind of light, known as synchrotron emission, which displays a characteristic pattern of polarization. It is this polarization that the team have found in the gamma rays. It was a difficult observation to make.
“We had to use almost every observation Integral has ever made of Cygnus X-1 to make this detection,” says Laurent.
Amassed over seven years, these repeated observations of the black hole now total over five million seconds of observing time, the equivalent of taking a single image with an exposure time of more than two months. Laurent’s team added them all together to create just such an exposure.
“We still do not know exactly how the infalling matter is turned into the jets. There is a big debate among theoreticians; these observations will help them decide,” says Laurent.
Jets around black holes have been seen before by radio telescopes but such observations cannot see the black hole in sufficient detail to know exactly how close to the black hole the jets originate. That makes these new observations invaluable. Such polarization measurements can provide direct insights into the nature of many astrophysical processes and the researchers say that, in the future, their discovery could further our understanding of the emission mechanisms of Cygnus X-1, a model for other black-hole binaries in the universe.
Source: Science. The paper appears today, at the Science Express website.
Sea ice data through mid- March 2011. Credit: National Snow and Ice Data Center
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Bad news for what is now the beginning of the “melt season” in the Arctic. Right now, the sea ice extent maximum appears to be tied for the lowest ever measured by satellites as the spring begins, according to scientists at the University of Colorado Boulder’s National Snow and Ice Data Center. And because of the trend of how the amount of Arctic sea ice has been spiraling downward in the last decade, some scientists are predicting the Arctic Ocean may be ice free in the summers within the next several decades.
“I’m not surprised by the new data because we’ve seen a downward trend in winter sea ice extent for some time now,” said Walt Meier, a research scienitist with the NSIDC.
The seven lowest maximum Arctic sea ice extents measured by satellites all have occurred in the last seven years, and the from the latest data, the NSIDC research team believes the lowest annual maximum ice extent of 5,650,000 square miles occurred on March 7 of this year.
The maximum ice extent was 463,000 square miles below the 1979-2000 average, an area slightly larger than the states of Texas and California combined. The 2011 measurements were tied with those from 2006 as the lowest maximum sea ice extents measured since satellite record keeping began in 1979.
Virtually all climate scientists believe shrinking Arctic sea ice is tied to warming temperatures in the region caused by an increase in human-produced greenhouse gases being pumped into Earth’s atmosphere.
Meier said the Arctic sea ice functions like an air conditioner for the global climate system by naturally cooling air and water masses, playing a key role in ocean circulation and reflecting solar radiation back into space. In the Arctic summer months, sunlight is absorbed by the growing amounts of open water, raising surface temperatures and causing more ice to melt.
“I think one of the reasons the Arctic sea ice maximum extent is declining is that the autumn ice growth is delayed by warmer temperatures and the ice extent is not able to ‘catch up’ through the winter,” said Meier. “In addition, the clock runs out on the annual ice growth season as temperatures start to rise along with the sun during the spring months.”
Since satellite record keeping began in 1979, the maximum Arctic sea ice extent has occurred as early as Feb. 18 and as late as March 31, with an average date of March 6. Since the researchers determine the maximum sea ice extent using a five-day running average, there is small chance the data could change.
As of March 22, ice extent declined for five straight days. But February and March tend to be quite variable, so there is still a chance that the ice extent could expand again. Ice near the edge is thin and is highly sensitive to weather, scientists say, moving or melting quickly in response to changing winds and temperatures, and it often oscillates near the maximum extent for several days or weeks, as it has done this year.
In early April the NSIDC will issue a formal announcement on the 2011 maximum sea ice extent with a full analysis of the winter ice growth season, including graphics comparing 2011 to the long-term record.
It’s time once more for another Where In The Universe Challenge (sorry for the short hiatus…) Name where in the Universe this image was taken and give yourself extra points if you can name the telescope or spacecraft responsible for the image. Post your guesses in the comments section, and check back on later at this same post to find the answer. To make this challenge fun for everyone, please don’t include links or extensive explanations with your answer. Good luck!
UPDATE: The answer is now posted below:
It took awhile, but readers finally figured this one out! This our Moon as seen from the MESSENGER spacecraft back on July 31, 2005, less than a year after it launched. As you know, MESSENGER is now successfully in orbit around Mercury (yay!) but at the time this image was taken, the spacecraft was about 992,814 kilometers (616,906 miles) from the Earth on its circuitous route to Mercury.
This image was featured on the Lunar Reconnaissance Orbiter website last week in honor of MESSENGER’s successful orbit insertion. As the LROC website says, this image was not taken simply because the Moon is beautiful and inspiring; it served to help the MESSENGER team calibrate the camera and spectrometer. The Moon is a good calibration standard because its reflectance and color have been measured with many instruments, so it is useful to make comparisons between instruments with different characteristics.
So congrats to the MESSENGER team — who will certainly henceforth be concentrating on Mercury!
The second edition of "How Apollo Flew To The Moon" is set to be released this summer. Image Credit: Springer/Praxis
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Apollo: the name conjures up images of spacesuit-clad astronauts riding fantastic machines to the surface of another world. But when it comes to the brass tacks, the mechanics of how it was accomplished – the image gets a little fuzzy.
It is with that in mind that author, engineer and historian David Woods has written: How Apollo Flew to the Moon. Now while this book is written by someone that has sat down with those involved with the Apollo Program and is an engineer himself – it doesn’t read that way. This appears to be one of Woods’ key considerations from the outset.
“I believe that the essential elements of any technology can be understood by any reasonably intelligent person, provided that the words can be found to explain it,” said Woods during an interview regarding the second edition of his book which was recently released. “This was the basis for this book. There’s no point in getting into the function of every electronic component or each equation used to describe a trajectory to the Moon, but I could see no reason why a person couldn’t come to understand the broad sweep of a mission and the many layers of technology and procedure that went into one.”
Many books that cover the Apollo Program delve a little too deeply into the technical aspects that made man’s first journey to another world possible. Novices, or those without engineering degrees get quickly bored and the books find themselves warming shelves.
How Apollo Flew To The Moon defeats this problem by breaking the technical hurdles, accomplishments and other aspects of the missions into bite-sized segments. It also avoids engineer-speak, explaining points in easy-to-understand language. It also is filled with color and black-and-white images as well as diagrams that explain how things happened, why other things were selected (and others weren’t) and so on.
The first edition of the book can be found on Amazon.com for around $30, whereas the newly updated second edition will set you back around $44.95. Given the attention to detail that is contained within this tome – it is well worth the additional cost to pick up the newer edition. How Apollo Flew To The Moon, second edition, is available for preorder from Amazon.com and other outlets. The book is scheduled to be released this summer.
“The book’s initial reception has been fantastic and I have been deeply humbled by folk’s kind words about it since it first came out,” Woods said. “The second edition is nearly ready and it expands on what was written in the first edition. At over 500 pages, it will be 25 percent larger with more color photographs throughout. There are additional stories of Apollo’s engineering triumphs both on the surface of the Moon as well as in flight, much of which reflects my continuing journey into the technical achievement that was Apollo.”
The first edition cover of "How Apollo Flew To The Moon." Image Credit: Springer/Praxis
Virtual Vesta. Taking their best guess, the science team on NASA’s Dawn Asteroid Orbiter have created a series of still images and videos (see below) to simulate what the protoplanet Vesta might look like. The exercise was carried out by mission planners at NASA's Jet Propulsion Laboratory and science team members at the German Aerospace Center and the Planetary Science Institute. Image credit: NASA/JPL-Caltech/ESA/UCLA/DLR/PSI/STScI/UMd
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The excitement is building as NASA’s innovative Dawn spacecraft closes in on its first protoplanetary target, the giant asteroid Vesta, with its camera eyes now wide open. The probe is on target to become the first spacecraft from Earth to orbit a body in the main asteroid belt and is set to arrive about four months from now in late July 2011.
Vesta is the second most massive object in the Asteroid Belt between Mars and Jupiter (map below). Since it is also one of the oldest bodies in our Solar System, scientists are eager to study it and search for clues about the formation and early history of the solar system. Dawn will spend about a year orbiting Vesta. Then it will fire its revolutionay ion thrusters and depart for Ceres, the largest asteroid in our solar system.
Dawn is equipped with three science instruments to photograph and investigate the surface mineralogy and elemental composition of the asteroid. The instruments were provided by the US, Germany and Italy. The spacecraft has just awoken from a six month hibernation phase. All three science instruments have been powered up and reactivated.
Dawn will image about 80 percent of Vesta’s surface at muliple angles with the onboard framing cameras to generate topographical maps. During the year in orbit, the probe will adjust its orbit and map the protoplanet at three different and decreasing altitudes between 650 and 200 kilometers, and thus increasing resolution. The cameras were provided and funded by Germany.
To prepare for the imaging campaign, mission planners from the US and Germany conducted a practice exercise to simulate the mission as though they were mapping Vesta. The effort was coordinated among the science and engineering teams at NASA’s Jet Propulsion Laboratory, the Institute of Planetary Research of the German Aerospace Center (DLR) in Berlin and the Planetary Science Institute in Tuscon, Ariz.
Simulated Vesta from the South Pole
This image shows the scientists' best guess to date of what the surface of the protoplanet Vesta might look like from the south pole, as projected onto a sphere 250 kilometers (160 miles) in radius. It was created as part of an exercise for NASA's Dawn mission involving mission planners at NASA's Jet Propulsion Laboratory and science team members at the Planetary Science Institute in Tuscon, Ariz. Credit: NASA/JPL-Caltech/UCLA/PSI
“We won’t know what Vesta really looks like until Dawn gets there,” said Carol Raymond in a NASA statement. Raymond is Dawn’s deputy principal investigator, based at JPL, who helped orchestrate the activity. “But we needed a way to make sure our imaging plans would give us the best results possible. The products have proven that Dawn’s mapping techniques will reveal a detailed view of this world that we’ve never seen up close before.”
Two teams worked independently and used different techniques to derive the topographical maps from the available data sets. The final results showed only minor differences in spatial resolution and height accuracy.
Using the best available observations from the Hubble Space Telescope and ground based telescopes and computer modeling techniques, they created maps of still images and a rotating animation (below) showing their best guess as to what Vesta’s surface actually looks like. The maps include dimples, bulges and craters based on the accumulated data to simulate topography and thus give a sense of Virtual Vesta in three dimensions (3 D).
“Working through this exercise, the mission planners and the scientists learned that we could improve the overall accuracy of the topographic reconstruction, using a somewhat different observation geometry,” said Nick Mastrodemo, Dawn’s optical navigation lead at JPL. “Since then, Dawn science planners have worked to tweak the plans to implement the lessons of the exercise.”
Dawn launch on September 27, 2007 by a Delta II rocket from Cape Canaveral Air Force Station, Florida. Credit: Ken KremerOf course no one will know how close these educated guesses come to matching reality until Dawn arrives at Vesta.
The framing camera system consists of two identical cameras developed and built by the Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany and the German Aerospace Center (DLR) in Berlin.
“The camera system is working flawlessly. The dry run was a complete success,” said Andreas Nathues, lead investigator for the framing camera at the Max Planck Institute in Katlenburg-Lindau, Germany.
Since the probe came out of hibernation, the mechanical and electrical components were checked out in mid March and found to be in excellent health and the software was updated.
Dawn is a mission of many firsts.
Dawn spacecraft under construction in Cleanroom.
Picture shows close up view of two science instruments;
The twin Framing Cameras at top (white rectangles) and VIR Spectrometer at right. Credit: Ken Kremer The spacecraft is NASA’s first mission specifically to the Asteroid Belt. It will become the first mission to orbit two solar system bodies.
The revolutionary Dawn mission is powered by exotic ion propulsion which is vastly more efficient than chemical propulsion thrusters. Indeed the ability to orbit two bodies in one mission is only enabled via the use of the ion engines fueled by xenon gas.
Vesta and Ceres are very different worlds that orbit between Mars and Jupiter. Vesta is rocky and may have undergone volcanism whereas Ceres is icy and may even harbor a subsurface ocean conducive to life.
Dawn will be able to comparatively investigate both celestial bodies with the same set of science instruments and try to unlock the mysteries of the beginnings of our solar system and why they are so different.
Dawn is part of NASA’sDiscovery program and was launched in September 2007 by a Delta II rocket from Cape Canaveral Air Force Station, Florida.
Virtual Vesta in 2 D.
This image shows a model of the protoplanet Vesta, using scientists' best guess to date of what the surface of the protoplanet might look like. The images incorporate the best data on dimples and bulges of Vesta from ground-based telescopes and NASA's Hubble Space Telescope. The cratering and small-scale surface variations are computer-generated, based on the patterns seen on the Earth's moon, an inner solar system object with a surface appearance that may be similar to Vesta. Credit: NASA/JPL-Caltech/UCLA/PSIVirtual Vesta in 3 D.
This anaglyph -- best viewed through red-blue glasses -- shows a 3-D model of the protoplanet Vesta, using scientists' best guess to date of what the surface of the protoplanet might look like. Image credit: NASA/JPL-Caltech/UCLA/PSI Dawn Spacecraft current location approaching Asteroid Vesta on March 21, 2011
The boundary where Earth’s crust gives way to the unexplored mantle was first detected in 1909, because of a change in the travel of seismic waves. Named the Moho boundary for Andrija Mohorovicic, who listened to those seismic waves, the crust-mantle boundary is a frontier that remains elusive and compelling — harboring tantalizing clues as to the story of Earth’s formation — even as our technologies push into the outer reaches of the solar system and beyond.
The first serious attempts to probe the Moho boundary ran aground in the late 1950s. Now, technology already in use on a Japanese ship, combined with a United States digging program already under way, could finally yield success. Damon Teagle and Benoît Ildefonse have written about the ongoing efforts for an article in the journal Nature, released today.
Teagle is at the University of Southampton’s National Oceanography Centre in the UK, and Ildefonse is at Université Montpellier in France. They are co-chief scientists on an expedition called the IODP Expedition 335, “to obtain for the first time a section of the lower oceanic crust — the material lying just above the mantle,” they write.
The IODP is using the U.S. ship JOIDES Resolution, pictured above, which will drill from April to June this year off the coast of Costa Rica.
“This site is in ocean crust that formed superfast — at more than 20 centimetres a year, much faster than any present day crust formation,” the co-authors write. “That makes the upper crust there much thinner than elsewhere, so it is possible to reach the lower portions without having to drill very deep. Three previous expeditions to Hole 1256D have drilled down to more than 1.5 kilometres below the sea floor, into the transition zone between dikes and gabbros.”
This spring they hope to push it another 400 meters, and recover gabbros from the lower crust, “which will be the deepest types of rock ever extracted from beneath the sea floor,” even though the deepest hole reached 2,111 meters under the eastern Pacific off of Colombia, they write.
Microphotograph of a mantle xenolith, sampled on Rapa Island in French Polynesia. The colourful minerals (seen here under the microscope in cross-polarized light, each grain is about 1 to 5mm large) are olivine, the main constituent of the upper mantle. Credit : Andréa Tommasi (CNRS, Géosciences Montpellier)
Teagle and Ildefonse note that some pieces of the mantle have been thrust up to Earth’s surface during tectonic mountain building, and ejected from volcanoes and sea floor dikes. Those samples have provided clues to the mantle’s composition, but they don’t reveal the variability of the mantle — and all of the samples have been altered by the processes that revealed them.
They say the IODP mission should help to settle many debates, including how crust is formed at mid-ocean ridges, how magma from the mantle is intruded into the lower crust, the geometry and vigor of how sea water can pull heat from the lower oceanic crust and the contribution of the lower crust to marine magnetic anomalies. The project will also provide “further impetus for, and confidence in, deep ocean crust drilling,” write Teagle and Ildefonse — but it will reach a depth far less than what will be needed to actually get at the Moho boundary. It occurs at least 30 kilometers (18 miles) under the continents but just 6 kilometers (3.7 miles) under the seas.
That’s where Chikyu comes in. Launched in 2002, “Chikyu is a giant ship, capable of carrying 10 kilometres of drilling pipes, and is equipped for riser drilling in 2.5 kilometres of water,” the authors write. Although Chikyu wouldn’t yet be able to go the full distance, its design is advanced enough to be the launching pad for such efforts:
“The vessel has a riser system: an outer pipe surrounds the drill string — the steel pipe through which cores are recovered,” the co-authors write. “The drilling mud and cuttings are returned up to the vessel in the space between the two pipes. This helps to recycle the drilling mud, control its physical properties and the pressure within the drill hole and helps to stabilize the borehole walls.”
Teagle and Ildefonse say the ideal drilling program to reach the mantle boundary will happen in one of three places — off the coasts of Hawaii, Baja California and Costa Rica — where the water is the most shallow, over the coldest possible crust. Wherever and however it happens, they write, it will be worth doing:
“Drilling to the mantle is the most challenging endeavour in the history of Earth science. It will provide a legacy of fundamental scientific knowledge, and inspiration and training for the next generation of geoscientists, engineers and technologists.”
Source: Nature. See also the websites for Chikyu and JOIDES.
Cover of Augustine Commision Report. We're still seeking a human spaceflight program
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Over at Space Politics, Jeff Foust points out that a provision for an independent study about human spaceflight was quietly included in last year’s NASA authorization act. The parameters of such a study would be similar to the decadal surveys done by the astronomy and planetary science disciplines. Foust reports that last week such a concept for human spaceflight was debated at a small conference where NASA’s Phil McAlister from the Office of Program Analysis and Evaluation said, “I believe in this Academies-like study that will allow the human spaceflight community to come together, like the science community has done for years and years, effectively. With that kind of document and blueprint… then finally, maybe, we can get the long-term consensus required to actually finish one of these programs. That is my sincere hope.”
Would such a study be helpful in giving U.S. human spaceflight unwavering direction and goals that don’t change with each presidential administration?
The debate is continuing in the comment section on Foust’s article and on Twitter, and so far the lines are divided between this being a good idea or one that would never work for human spaceflight.
Some comments suggest this type of survey would be just another exercise on paper that will accomplish nothing – and would be a repeat of the Stafford Report or the Augustine Commission, where programs and direction is suggested, but since it isn’t “law” politicians would ignore it in favor of projects in their own districts.
Others said there isn’t a strong figure in human spaceflight, such as a Steve Squyres who led the recent planetary decadal survey (although someone suggested Wayne Hale or Bill Gerstenmaier).
On the other side of the debate, still others said that some kind of consensus review is needed in order to direct NASA’s priorities with human space flight, as there has been no clear sustainable direction since the decision to build the ISS. Someone suggested this would be helpful for the international partner, as well, to know what NASA might do next.
What are your views – would a decadal survey for US human spaceflight be a good idea?
Iran’s Fars News Agency revealed that the country has built an unmanned flying saucer, named “Zohal” (Saturn in Persian) which will be used for various missions including aerial imaging. UPDATE: thanks to reader Robert McCelland, we now have an actual picture of the Zohal instead of the hoaky flying saucer image that was included in the Fars article (see below). It is not really all that big — more like a remote controlled toy helicopter — but reportedly the Zohal is equipped with an auto-pilot system, GPS and two separate imaging systems with full HD 10 mega-pixel picture quality and is able to take and send images simultaneously. It was unveiled in a ceremony attended by Supreme Leader of the Islamic Revolution Ayatollah Seyed Ali Khamenei at an exhibition of strategic technologies.
No detailed specifications were supplied such as exact size and flight capabilities, (except that it can fly vertically) but the report said it could fly both indoors and outside.
The craft was designed and developed jointly by Farnas Aerospace Company and Iranian Aviation and Space Industries Association (IASIA).
The original image on the Fars site:
This image accompanied a news article in Iran about the country's own flying saucer.
Artst concept of the Kepler telescope in orbit. Credit: NASA
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NASA’s Kepler spacecraft is back in planet-hunting action after a computer malfunction put it into “safe mode” for 144 hours (six days.) The anomaly occurred on March 14, 2011 immediately after the spacecraft issued a network interface card (NIC) reset command to start a computer program update. During the reset, the NIC sent invalid reaction wheel data to the flight software, which caused the spacecraft to enter the self-protecting safe mode. The NIC is the interfaces between the spacecraft’s flight software, attitude determination, and its control subsystems and sensors. Mission managers said an anomaly response team will continue to evaluate the spacecraft data to determine the cause of the safe mode event.
A safe mode is a measure the spacecraft takes to protect itself when something unexpected occurs. Kepler mission managers described what happens during a safe mode event:
“During safe mode, the spacecraft points the solar panels directly at the sun and begins to slowly rotate along a sun-aligned axis. This safe mode orientation provides the vehicle with the maximum power and limits the buildup of momentum from solar wind. The spacecraft also swapped to its backup subsystem interface box (SIB), an electronics component that provides thermal and power distribution control to all spacecraft subsystems, and powered off the photometer, the instrument used to measure light intensity to detect planets. This is a normal procedure when the spacecraft enters safe mode.”
Kepler spacecraft returned to science data collection at 2:45 p.m. EDT Sunday, March 20, 2011.
Kepler launched in 2009 to look for alien worlds, hoping to find one like Earth in the just-right “Goldilocks Zone” around another star. So far, Kepler has discovered 1,235 possible planets, with 54 of those candidates in that potential habitable zone where liquid water could exist on a planet’s surface. Further study is needed to see if any of these planets have the potential to harbor life.
But given how many potential habitable planets were found in just one area of the sky, astronomers have estimated that our Milky Way galaxy could hold as many as 50 billion alien planets, with 2 billion of those being about the size of Earth.
