Tag: Alpha Centauri

The Pale Red Dot Campaign

Alpha and Beta Centauri are the bright stars; Proxima Centauri is the small, faint one circles in red.

Alpha Centauri A and B are the bright stars; Proxima Centauri, a red dwarf star, is the small, faint one circled in red. (NASA, Julia Figliotti)

Astronomers have been trying for decades to find a planet orbiting Proxima Centauri, the star closest to our sun and so a natural and tempting target.  Claims of an exoplanet discovery have been made before, but so far none have held up.

Now, in a novel and very public way, a group of European astronomers have initiated a focused effort to change all that with their Pale Red Dot Campaign.  Based at the La Silla Observatory in Chile, and supported by  networks of smaller telescopes around the world, they will over the next three months observe Proxima and its environs and then will spend many more months analayzing all that they find.

And in an effort to raise both knowledge and excitement, the team will tell the world what they’re doing and finding over Twitter, Facebook, blogs and other social and traditional media of all kind.

“We have reason to be hopeful about finding a planet, but we really don’t know what will happen,” said Guillem Anglada-Escudé  of Queen Mary University, London, one of the campaign organizers.  “People will have an opportunity to learn how astronomers do their work finding exoplanets, and they’ll be able to follow our progress.  If we succeed, that would be wonderful and important.  And if no planet is detected, that’s very important too.”

The Pale Blue Dot, as photographed by Voyager 1 (NASA)

The Pale Blue Dot, as photographed by Voyager 1 (NASA)

The name of the campaign is, of course, a reference to the iconic “Pale Blue Dot” image of Earth taken by the Voyager 1 spacecraft in 1990, when it was well beyond Pluto.  The image came to symbolize our tiny but precious place in the galaxy and universe.

But rather than potentially finding a pale blue dot, any planet orbiting the red dwarf star Proxima Centauri would reflect the reddish light of the the star, which lies some 4.2 light years away from our solar system.  Proxima — as well as 20 of the 30 stars in our closest  neighborhood — is reddish because it is considerably smaller and less luminous than a star like our sun.

Anglada-Escudé said he is cautiously optimistic about finding a planet because of earlier Proxima observations that he and colleagues made at the same observatory.  That data, he said, suggested the presence of a planet 1.2… Read more

Counting Our Countless Worlds

The Milky Way has several hundred billion stars, and many scientists are now convinced it has even more planets and moons. (NASA)

The Milky Way is home to several hundred billion stars, and many scientists are now convinced it has even more planets and moons. (NASA)

Imagine counting all the people who have ever lived on Earth, well over 100 billion of them.

Then imagine counting all the planets now orbiting stars in our Milky Way galaxy , and in particular the ones that are roughly speaking Earth-sized. Not so big that the planet turns into a gas giant, and not so small that it has trouble holding onto an atmosphere.

In the wake of the explosion of discoveries about distant planets and their suns in the last two decades, we can fairly conclude that one number is substantially larger than the other.

Yes, there are many, many billions more planets in our one galaxy than people who have set foot on Earth in all human history. And yes, there are expected to be more planets in distant habitable zones as there are people alive today, a number upwards of 7 billion.

This is for sure a comparison of apples and oranges. But it not only gives a sense of just how commonplace planets are in our galaxy (and no doubt beyond), but also that the population of potentially habitable planets is enormous, too.   “Many Worlds,” indeed.

 

The populations of exoplanets identified so far, plotted according to the radius of the planet and how many days it takes to orbit. The circles in yellow represent planets found by Kepler, light blue by using ground-based radial velocity, and pink for transiting planets not found by Kepler, and green, purple and red other ground-based methods. (NASA Ames Research Center)

The populations of exoplanets identified so far, plotted according to the radius of the planet and how many days it takes to orbit. The circles in yellow represent planets found by Kepler, light blue by using ground-based radial velocity, and pink for transiting planets not found by Kepler, and green, purple and red other ground-based methods. (NASA Ames Research Center)

It was Ruslan Belikov, an astrophysicist at NASA’s Ames Research Center in Silicon Valley who provided this sense of scale.  The numbers are of great importance to him because he (and others) will be making recommendations about future NASA exoplanet-finding and characterization missions based on the most precise population numbers that NASA and the exoplanet community can provide.

Natalie Batalha, Mission Scientist for the Kepler Space Telescope mission and the person responsible for assessing the planet population out there, sliced it another way. When I asked her if her team and others now expect each star to have a planet orbiting it, she replied: “At least one.”

 

Kepler-186f was the first rocky planet to be found within the habitable zone -- the region around the host star where the temperature is right for liquid water. This planet is also very close in size to Earth. (NASA Ames/SETI Institute/JPL-Caltech)

Kepler-186f was the first rocky planet to be found within the habitable zone — the region around the host star where the temperature is right for liquid water.

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