<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="There are at least 300 million habitable planets in the Milky Way, new NASA research has shown – hinting that it’s less likely that humanity is alone in the universe.” data-reactid=”32″>There are at least 300 million habitable planets in the Milky Way, new NASA research has shown – hinting that it’s less likely that humanity is alone in the universe.
<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="That means the planets could potentially harbour life, scientists believe. ” data-reactid=”34″>That means the planets could potentially harbour life, scientists believe.
Some of these potential planets are also very close to Earth (relatively speaking) with the closest likely to be a mere 20 light years away.
Four are within 30 light years of Earth, the researchers say.
“Kepler already told us there were billions of planets, but now we know a good chunk of those planets might be rocky and habitable,” said the lead author Steve Bryson, a researcher at NASA’s Ames Research Center in California’s Silicon Valley.
“Though this result is far from a final value, and water on a planet’s surface is only one of many factors to support life, it’s extremely exciting that we calculated these worlds are this common with such high confidence and precision.”
These are the minimum numbers of such planets based on the most conservative estimate that 7% of Sun-like stars host such worlds.
However, at the average expected rate of 50%, there could be many more.
For the purposes of calculating this occurrence rate, the team looked at exoplanets between a radius of 0.5 and 1.5 times that of Earth’s, narrowing in on planets that are most likely rocky.
This new finding is a significant step forward in Kepler’s original mission to understand how many potentially habitable worlds exist in our galaxy.
Previous estimates of the frequency, also known as the occurrence rate, of such planets ignored the relationship between the star’s temperature and the kinds of light given off by the star and absorbed by the planet.
The new analysis accounts for these relationships, and provides a more complete understanding of whether or not a given planet might be capable of supporting liquid water, and potentially life.
That approach is made possible by combining Kepler’s final dataset of planetary signals with data about each star’s energy output from an extensive trove of data from the European Space Agency’s Gaia mission.
“We always knew defining habitability simply in terms of a planet’s physical distance from a star, so that it’s not too hot or cold, left us making a lot of assumptions,” said Ravi Kopparapu, an author on the paper and a scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
“Gaia’s data on stars allowed us to look at these planets and their stars in an entirely new way.”
“Not every star is alike,” said Kopparapu. “And neither is every planet.”
According to a new map of the Milky Way galaxy, the Solar System’s position isn’t where we thought it was. Not only is it closer to the galactic centre – and the supermassive hole therein, Sagittarius A* – it’s orbiting at a faster clip.
It’s nothing to be concerned about; we’re not actually moving closer to Sgr A*, and we’re in no danger of being slurped up. Rather, our map of the Milky Way has been adjusted, more accurately identifying where we have been all along.
And the survey beautifully demonstrates how tricky it is to map a galaxy in three dimensions from inside it.
It’s a problem that has long devilled our understanding of space phenomena. It’s relatively easy to map the two-dimensional coordinates of stars and other cosmic objects, but the distances to those objects is a lot harder to figure out.
And distances are important – they help us determine the intrinsic brightness of objects. A good recent example of this is the red giant star Betelgeuse, which turned out to be closer to Earth than previous measurements suggested. This means that it’s neither as large nor as bright as we thought.
Another is the object CK Vulpeculae, a star that exploded 350 years ago. It’s actually much farther away, which means that the explosion was brighter and more energetic, and requires a new explanation, since previous analyses were performed under the assumption it was relatively low energy.
But we’re getting better at calculating those distances, with surveys using the best available technology and techniques working hard to refine our three-dimensional maps of the Milky Way, a field known as astrometry. And one of these is the VERA radio astronomy survey, conducted by the Japanese VERA collaboration.
VERA stands for VLBI (Very Long Baseline Interferometry) Exploration of Radio Astrometry, and it uses a number of radio telescopes across the Japanese archipelago, combining their data to effectively produce the same resolution as a telescope with a 2,300 kilometre- (1,430 mile-) diameter dish. It’s the same principle behind the Event Horizon Telescope that produced our very first direct image of a black hole’s shadow.
VERA, which started observing in 2000, is designed to help us calculate the distances to radio-emitting stars by calculating their parallax. With its incredible resolution, it observes these stars for over a year, and watches how their position changes relative to stars that are much farther away as Earth orbits the Sun.
(National Astronomical Observatory of Japan)
This change in position can then be used to calculate how far a star is from Earth, but not all parallax observations are created equal. VLBI can produce much higher resolution images; VERA has a breathtaking angular resolution of 10 millionths of an arcsecond, which is expected to produce extraordinarily high precision astrometry measurements.
And this is what astronomers have used to refine our Solar System’s position in the Milky Way. Based on the first VERA Astrometry Catalog of 99 objects released earlier this year, as well as other observations, astronomers created a position and velocity map of those objects.
From this map, they calculated the position of the galactic centre.
In 1985, the International Astronomical Union defined the distance to the galactic centre as 27,700 light-years. Last year, the GRAVITY collaboration recalculated it and found it closer, just 26,673 light-years away.
(National Astronomical Observatory of Japan)
The VERA-based measurements bring it closer still, to a distance of just 25,800 light-years. And the Solar System’s orbital speed is faster, too – 227 kilometres (141 miles) per second, rather than the official velocity of 220 kilometres (137 miles) per second.
That change may not seem like much, but it could have an impact on how we measure and interpret activity in the galactic centre – ultimately, hopefully, leading to a more accurate picture of the complex interactions around Sgr A*.
Meanwhile, the VERA collaboration is forging ahead. Not only is it continuing to make observations of objects in the Milky Way, it’s joining up with an even larger project, the East Asian VLBI Network. Together, astronomers hope, the telescopes involved in this project could provide measurements of unprecedented accuracy.
Great news! It turns out scientists have discovered that we’re 2,000 light-years closer to Sagittarius A* than we thought.
This doesn’t mean we’re currently on a collision course with a black hole. No, it’s simply the result of a more accurate model of the Milky Way based on new data.
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Over the last 15 years, a Japanese radio astronomy project, VERA, has been gathering data. Using a technique called interferometry, VERA gathered data from telescopes across Japan and combined them with data from other existing projects to create what is essentially the most accurate map of the Milky Way yet.
By pinpointing the location and velocity of around 99 specific points in our galaxy, VERA has concluded that the supermassive black hole Sagittarius A, at the center of our galaxy, is actually 25,800 light-years from Earth — almost 2,000 light-years closer than what we previously believed.
In addition, the new model calculates Earth is moving faster than we believed. Older models clocked Earth’s speed at 220 kilometers (136 miles) per second, orbiting around the galaxy’s centre. VERA’s new model has us moving at 227 kilometers (141 miles) per second.
VERA is now hoping to increase the accuracy of its model by increasing the amount of points it’s gathering data from by expanding into EAVN (East Asian VLBI Network) and gathering data from a larger suite of radio telescopes located throughout Japan, Korea and China.
Researchers have effectively confirmed one of the most important theories in star physics. NBC Newsreports that a team at the Italian National Institute for Nuclear Physics has detected neutrinos traced back to star fusion for the first time. The scientists determined that the elusive particles passing through its Borexino detector stemmed from a carbon-nitrogen-oxygen (CNO) fusion process at the heart of the Sun.
This kind of behavior had been predicted in 1938, but hadn’t been verified until now despite scientists detecting neutrinos in 1956. Borexino’s design was crucial to overcoming that hurdle — its “onion-like” construction and ongoing refinements make it both ultra-sensitive and resistant to unwanted cosmic radiation.
It’s a somewhat surprising discovery, too. CNO fusion is much more common in larger, hotter stars. A smaller celestial body like the Sun only produces 1 percent of its energy through that process. This not only confirms that CNO is a driving force behind bigger stars, but the universe at large.
That, in turn, might help explain some dark matter, where neutrinos could play a significant role. Scientist Orebi Gann, who wasn’t involved in these findings, also told NBC that an asymmetry between neutrinos and their relevant antiparticles might explain why there isn’t much known antimatter in the universe. To put it another way, the findings could help answer some of the most basic questions about the cosmos.
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