NASA discovers Earth-like planet orbiting 'cousin' of Sun

This NASA artist's concept obtained July 23, 2015 compares Earth (L) to the new planet, called Kepler-452b, which is about 60 pe
This NASA artist's concept obtained July 23, 2015 compares Earth (L) to the new planet, called Kepler-452b, which is about 60 percent larger in diameter

Astronomers hunting for another Earth have found what may be the closest match yet, a potentially rocky planet circling its star at the same distance as the Earth orbits the Sun, NASA said Thursday.

Not only is this planet squarely in the Goldilocks zone—where life could exist because it is neither too hot nor too cold to support liquid water—its star looks like an older cousin of our Sun, the US space agency said.

That means the planet, which is 1,400 light-years away, could offer a glimpse into the Earth's apocalyptic future, scientists said.

Known as Kepler 452b, the planet was detected by the US space agency's Kepler Space Telescope, which has been hunting for other worlds like ours since 2009.

"Kepler 452b is orbiting a close cousin of our Sun, but one that is 1.5 billion years older," NASA said in a statement.

Its star is four percent more massive than the Sun and 10 percent brighter.

If the planet is rocky, and scientists believe that it has a better than even chance of being just that, then it could be in the midst of a fearful scenario, as the heat from its dying star evaporates Kepler 452b's lakes and oceans.

"If Kepler 452b is indeed a , its location vis-a-vis its star could mean that it is just entering a runaway greenhouse phase of its climate history," said Doug Caldwell, a Search for Extraterrestrial Intelligence (SETI) Institute scientist working on the Kepler mission.

NASA discovers Earth-like planet orbiting 'cousin' of Sun
There are 4,696 planet candidates now known with the release of the seventh Kepler planet candidate catalog - an increase of 521 since the release of the previous catalog in January 2015. Credits: NASA/W. Stenzel
"The increasing energy from its aging might be heating the surface and evaporating any oceans. The water vapor would be lost from the planet forever," he added.

"Kepler 452b could be experiencing now what the Earth will undergo more than a billion years from now, as the Sun ages and grows brighter."

This NASA artist concept obtained on December 19, 2014 shows NASA's planet-hunting Kepler spacecraft operating in a new mission
This NASA artist concept obtained on December 19, 2014 shows NASA's planet-hunting Kepler spacecraft operating in a new mission profile called K2
Planetary catalog

The Kepler mission launched in 2009 to search for exoplanets, which are planets outside our solar system, particularly those about the size of Earth or smaller.

"Today, and thousands of discoveries later, astronomers are on the cusp of finding something people have dreamed about for thousands of years—another Earth," NASA said in a statement.

On Thursday, NASA released the latest catalog of exoplanet candidates, adding more than 500 new possible planets to the 4,175 already found by the space-based telescope.

"This catalog contains our first analysis of all Kepler data, as well as an automated assessment of these results," said SETI Institute scientist Jeffrey Coughlin.

NASA's Kepler mission
NASA's Kepler mission

The new catalog includes 12 candidates that are less than twice the diameter of Earth and which are orbiting in the habitable zones of their .

Of those 12 new candidates, Kepler 452b "is the first to be confirmed as a planet," NASA said.

Kepler identifies possible planets by watching for dips in the brightness of stars, which could be caused by a planet passing between the star and the telescope.

NASA discovers Earth-like planet orbiting 'cousin' of Sun
Since Kepler launched in 2009, twelve planets less than twice the size of Earth have been discovered in the habitable zones of their stars. Credits: NASA/N. Batalha and W. Stenzel

Other scientific tools are needed to judge whether the planet is gassy or rocky.

The Kepler mission has cost NASA about $600 million, and the US space agency said in 2013 that two of its orientation wheels had lost function, leaving the space telescope beyond repair.

But scientists have years to pore over the data it has returned in order to narrow the search for Earth-like worlds.

Explore further

Kepler's six years in science (and counting)

© 2015 AFP

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User comments

Jul 23, 2015
Not so fast Kemo Sabay! It just may be a verry rainy place with lotsa water. See it is a bit larger than earth so could retain MORE water and hydrogen in its atmosphere for a longer time. Could be a bit steamy but quite possibly habitable. If so, it would remain so for a verrrry long time all things considered. Look, humans live for a hundred years if they are lucky and do not get run over by a bus or kicked in the head by a horse or some street thug doesnt render their guts for a quarter. This planet will be in good shape for millions of years yet. ALL planets have an 'expiration date', but like milk can be utilized before that time.

Jul 23, 2015
Stellar luminosity formula says that a star of 1.04 solar masses should have a luminosity 16.5% greater than the Sun, not just 10% more....and that's assuming same relative age vs same relative age.

This suggests the star is cooling with age, rather than warming with age as the standard stellar model claims.

Jul 23, 2015
This suggests the star is cooling with age, rather than warming with age as the standard stellar model claims.

If L/L_sun = (M/M_sun)^a, what value did you use for "a", and why?

Take a look at 23,000 stars plotted on an H-R diagram here: https://en.wikipe...sequence
Note the variation along the main sequence. You need to show some numbers, formulas and models. I'm guessing you'll want to modify (if not retract) your suggestion...

Jul 24, 2015
Gravity =~ 1.6^3= 4.1+ so it is not fit for human habitation.
ETA =~ 1400 x 4 = 5600 years travel time.
Likelihood of life surviving travel time =~ 1%/century ^56 = 0.
Why is this all significant?
We need to take care of our Earth, no ifs ands or buts.

Jul 24, 2015
Close, but no (certain) cigar.

But the press material had a better illustration that included the candidates. If most of those can be confirmed, and the overall statistics argue they can, the number of 452b lookalike candidates means that the ~ 50 % certainty of (having been) an Earth analog can be pushed to enough certainty. Seen over the set we can thus say with some certainty that we have netted an Earth analog, even if we won't know exactly which candidate it is. (Something similar will happen as we start to see potential inhabited planets.)

Jul 24, 2015
Very intriguing!
Density 10.4 g / cm3 means to that is formed of a lanthanide and transition elements, and of those with a large number of protons.
Temperature -8 to +17 means to that the orbit 452b closer orbit of Mars, the star quickly rotates about an axis (2o days or faster) than the Sun as well as that planet orbiting a star faster than 30 km / sec.
Geologically is active, but not as a Earth. Action of the volcano are rarely but significantly stronger.
It is not for, expect a significant greenhouse effect (as on Venus), or an atmosphere similar to Earth's.
Water should be present but in smaller quantities.
Planet ideal for acquiring of wealth in mining.

Jul 24, 2015
@Osiris: The NASA press conference mentioned that the larger mass of 452b gave it another 0-5 billion years of habitability under the circumstances. The problem is that it is 1.5 billion years older than Earth.

Most analysts have put it in as a potential venus analog (after having been an earth analog).

@job: Why is any of what you say significant? No one wants to move there, even less visit, it is much cheaper to do science from here. Looking for other life is not only a fascinating, long standing question, the results will help test the main theories of life emergence.

And everything in science is interconnected, so if you want to make the most of the planet we have, you should support, not troll, this science!

Nit: The surface acceleration is 2 g [as modeled in the HEC], not 4 as you claim (roughly mass/radius ~ 1.6^3/1.6 ~ 2.6). Humans who were born at the planet could live well there. (With a somewhat higher death rate from accidents and circulatory problems.)

Jul 24, 2015
Seplling error: "another 0-5 billion years" = another 0.5 billion years.

@wducks: Higher average density can come from higher core pressure with the same composition as Earth. It is a larger planet, you know.

Since the Kepler team didn't release a composition model, we just don't know yet. Possibly (and I think the press conference claimed that, as seen from the press material), they can't tell. It is a confounded problem, since different compositions can give the same average density.

Jul 24, 2015

I used 3.9 for "a" because that's what the formula says it should be.

Jul 24, 2015
Gravity =~ 1.6^3= 4.1+ so it is not fit for human habitation.
Well, now that's wrong. Actually, a person would feel about twice as heavy if we assume that Earth's density is equal to Kepler452b .

Which it probably is not. If Kepler 452b's density is significantly less but it was still 1.6 times as large, gravity might actually be weaker there. That's possible.

Jul 25, 2015
I used 3.9 for "a" because that's what the formula says it should be.
It says that where? Why not 4? No matter...

According to [1], "On average, KIC 8311864 [the host star] is slightly cooler, slightly larger, and about 60% more metal-rich than the Sun." They obtained an estimate for the mass of 1.07 (1.02 - 1.12) solar masses. So try 2.5% more massive and see what you get.

You also missed this from the "main sequence" wiki link: "Once nuclear fusion of hydrogen becomes the dominant energy production process ... the brightness and surface temperature of stars typically increase with age."


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