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Astronomers estimate 100 billion habitable Earth-like planets in the Milky Way, 50 sextillion in the universe

Featured image is an infrared image of the core of the Milky Way, captured by NASA’s Spitzer space telescope. Infrared imaging allows you to see many stars which are normally obscured by intergalactic dust.

Astronomers at the University of Auckland claim that there are actually around 100 billion habitable, Earth-like planets in the Milky Way — significantly more than the previous estimate of around 17 billion. There are roughly 500 billion galaxies in the universe, meaning there is somewhere in the region of 50,000,000,000,000,000,000,000 (5×1022) habitable planets. I’ll leave you to do the math on whether one of those 50 sextillion planets has the right conditions for nurturing alien life or not.

The previous figure of 17 billion Earth-like planets in the Milky Way came from the  Harvard-Smithsonian Center for Astrophysics in January, which analyzed data from the Kepler space observatory. Kepler essentially measures the dimming (apparent magnitude) of stars as planets transit in front of them — the more a star dims, the larger the planet. Through repeated observations we can work out the planet’s orbital period, from which we can usually derive the orbital distance and surface temperature. According to Phil Yock from the University of Auckland, Kepler’s technique generally finds “Earth-sized planets that are quite close to parent stars,” and are therefore “generally hotter than Earth [and not habitable].”

The University of Auckland’s technique, called gravitational microlensing, instead measures the number of Earth-size planets that orbit at twice the Sun-Earth distance. This results in a list of planets that are generally cooler than Earth — but by interpolating between this new list, and Kepler’s list, the Kiwi astronomers hope to generate a more accurate list of habitable, Earth-like planets. “We anticipate a number in the order of 100 billion,” says Yock.

Gravitational microlensing, an effect theorized by Einstein back in 1936, is exactly what it sounds like. Essentially, light emitted by a star is bent by the gravity of massive objects, ultimately allowing astronomers to work out just how large those objects are. Gravitational microlensing has been used in recent years to detect planets the size of Neptune or Jupiter, and now Yock his colleagues at the University of Auckland have proposed a new method for detecting Earth-sized planets. The astronomers hope to use this new microlensing technique with a huge suite of telescopes — located in Chile, South Africa, Australia, New Zealand, Hawaii, and Texas — to confirm their estimate of 100 billion Earth-like habitable planets.

Suffice it to say, if the Milky Way contains 100 billion Earth-like planets, and there’s somewhere in the region of 500 billion galaxies, then there’s an extremely high chance of other planets harboring life. As for how we’ll get to those planets, though — or, alternatively, how the residents of those planets will get to us — remains a very big question. The nearest probably-habitable planet is Tau Ceti e, which is 11.9 light years from Earth. The fastest spacecraft ever, Helios II, traveled at 43 miles per second (70km/s), or 0.000234c (the speed of light). At that speed it would take 51,000 years for a spacecraft to reach Tau Ceti e.

Harold White’s possible Alcubierre warp drive, and star shipIt gets worse: Helios II was only travelling that fast because it was orbiting close to the Sun; Voyager, for example, travels at just 8 miles per second (so, about 200,000 years to reach Tau Ceti e). To reach another star within a reasonable time period (say, 50-100 years) we would need a propulsion system that’s capable of around 0.1c (10% light speed). There are a few proposed methods for reaching such insane speeds (antimatter rockets, fusion rockets), but nothing that’s being immediately (and seriously) considered for interstellar travel. Who knows, maybe NASA’s warp drive will pan out? If they can work out the whole annihilating-the-star-system-upon-arrival issue, that is…

Gravitational microlensing unlocks the secret of alien life

Research paper: doi: 10.1093/mnras/stt318 – “Extending the planetary mass function to Earth mass by microlensing at moderately high magnification”




Extraterrestrial Life Could Feasibly Live in Salty Puddles on Mars

All Dried Up

Scientists found another possible place to look for extraterrestrial life on Mars. The Red Planet, recently discovered to have water just beneath its surface, could be dotted with puddles of mud with a high concentration of salts.

Investigating similar salty mud puddles on Earth, Wichita State University astrobiologists found that bacterial life could survive even after getting completely dried out, according to The finding doesn’t by any means guarantee that there is or ever was life on Mars, but it does suggest that Mars is more hospitable than scientists previously assumed.

Puddle Pity

The scientists, who presented their research at an American Society for Microbiology conference on Friday, put bacteria in jars with a solution of saltwater similar to that found on Mars, per They then left them to dry out and rehydrate as the water evaporated and condensed with changing temperatures, as it would on Mars.

“We have the first data showing the growth of bacteria after drying and then rehydration through humidity alone, in the presence of salts that absorb moisture from the air,” lead scientist Mark Schneegurt told

Next up, Schneegurt told, is to get the experimental conditions closer and closer to those of Mars in order to better test the limits of these particularly resilient microbes.

READ MORE: How Martian Microbes Could Survive in the Salty Puddles of the Red Planet []

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Scientists Think Black Holes Could Be Portals To Other Worlds

Very little is known about black holes, aside from the fact that they are the result of a dying star imploding on itself from the pressure of the gravity. One theory about the mechanics of black holes is that they might be portals to other galaxies, or other parts of a galaxy.

This is a relatively new theory, as scientists previously thought that attempting to travel through a black hole would destroy anyone who attempted it. In fact, some researchers still believe that the heat emanating from the black hole would entirely vaporize any spacecraft that would attempt to travel through it.

A team of scientists at the University of Massachusetts Dartmouth, believe that there are many different types of black holes, some of which would be easier to travel through than others. The team even believes that there are some black holes that a spacecraft would be able to pass through “gently.”

According to Gaurav Khanna, lead researcher on the team, “the reason that this is possible is that the relevant singularity inside a rotating black hole is technically “weak,” and thus does not damage objects that interact with it. At first, this fact may seem counter intuitive. But one can think of it as analogous to the common experience of quickly passing one’s finger through a candle’s near 2,000-degree flame, without getting burned.”

Scientists Think Black Holes Could Be Portals To Other Worlds 1

This illustration shows a black hole named Cygnus X-1, which is sucking the life out of a blue star beside it. Photo Credit: NASA/CXC/M.Weiss

Khanna’s team has been researching black holes for over 20 years, and they believe in this theory that some black holes would be possible to travel through.

“Under all conditions an object falling into a rotating black hole would not experience infinitely large effects upon passage through the hole’s so-called inner horizon singularity. This is the singularity that an object entering a rotating black hole cannot maneuver around or avoid. Not only that, under the right circumstances, these effects may be negligibly small, allowing for a rather comfortable passage through the singularity. In fact, there may no noticeable effects on the falling object at all. This increases the feasibility of using large, rotating black holes as portals for hyperspace travel,” Khanna says.

The researchers used a computer simulation to support their theory about calm black holes.

Scientists Think Black Holes Could Be Portals To Other Worlds 2

This graph depicts the physical strain on the spacecraft’s steel frame as it plummets into a rotating black hole. Photo Credit: Khanna/UMassD

For many years, scientists have only had theoretical models to help them imagine what a black hole looked like. No one had ever taken a photo of this phenomenon in space before, until earlier this year.

The images were captured thanks to a global network of telescopes called the Event Horizon Telescope.

Researchers found the apparent black hole in galaxy M87, according to Sheperd Doeleman, EHT Director and astrophysicist at the Harvard-Smithsonian Center for Astrophysics in Cambridge.

The black hole is 55 million light-years from Earth in the constellation Virgo, and it’s about 1,000 times as large as the Milky Way’s giant, which weighs the equivalent of roughly 4 million suns.

Scientists Think Black Holes Could Be Portals To Other Worlds 3

Black Hole / Photo: Event Horizon Telescope

In another incredible discovery that happened this year, scientists detected a “dark impactor” that has some researchers believe has been “blasting holes in our galaxy.” This force is not visible, and may not be made up of matter. This may be made up of some type of material that humans aren’t even familiar with. Human telescopes haven’t even been able to detect this material yet, but it is leaving a mark and that is how we know it is out there.

Ana Bonaca, is the researcher from the Harvard-Smithsonian Center for Astrophysics, who discovered evidence for the impactor.

Bonaca presented her evidence to her peers for the first time on April 15, at the conference of the American Physical Society in Denver. Bonca says that whatever this mysterious force is, it is creating a series of holes in our galaxy’s longest stellar stream, GD-1.

If you are not familiar with the term, stellar streams are basically rows of stars that move together across galaxies. Many times, these streams originate in smaller clusters of stars that collided with the galaxy.

Bonaca managed to make this discovery by keeping an eye on data from the Gaia mission, a European Space Agency program that maps billions of stars in our galaxy and tracks their movements across the sky. Bonaca cross referenced the information from the Gaia mission with observations from the Multi Mirror Telescope in Arizona.

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Martian sand dune looks like Starfleet logo

Image Credit: NASA
The dune looks very similar to the Starfleet logo. 

New images taken by NASA’s MRO HiRise camera show a sand dune formation with a rather familiar shape.

The photographs, which were captured by NASA’s Mars Reconnaissance Orbiter, have prompted some rather tongue-in-cheek references to Star Trek’s iconic insignia.

“Enterprising viewers will make the discovery that these features look conspicuously like a famous logo,” the HiRise team at the University of Arizona wrote in a Tweet.

Star Trek references aside, this intriguing formation and others like it have been helping scientists to learn more about the Red Planet’s atmosphere, temperature and topography.

This, in turn, will also help NASA to better plan out future manned missions.

Source: IB Times

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