Numbers of Stars, Planets in the Universe just Tripled

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Numbers of Stars, Planets in the Universe just Tripled

Numbers of stars in universe tripled

Thursday, 2 December 2010

by Heather Catchpole

Cosmos Online elliptical galaxy

The elliptical galaxy NGC 1132 and its surrounding region. Astronomers have dubbed NGC 1132 a "fossil group" because it contains an enormous amount of dark matter – but could it be just many more red dwarf stars?

 SYDNEY: There are three times as many stars in the universe as they had previously supposed - and "possibly trillions of Earths orbiting these stars" - say astronomers.

The startling find, published in the British journal Nature, has exciting implications for the discovery of new planets as well as theories on galaxy formation and dark matter.

Astronomers Pieter van Dokkum and Charles Conroy found greater than expected numbers of faint, small stars known as red dwarfs in relatively close galaxies as observed with Hawaii's twin Keck Telescopes.

"Possibly trillions of Earths"

More stars means potentially many more planets, says lead author and astronomer van Dokkum, from Yale University, Connecticut: "There are possibly trillions of Earths orbiting these stars," he said.

There are currently 504 known exoplanets, most of which are large gaseous planets similar to or larger than Jupiter. But Earth-like planets have been found around red dwarf stars, including Gliese 581, a red dwarf whose planet count was recently [Sept] updated to six.

The red dwarf stars that the team discovered are typically more than 10 billion years old, old enough for complex life to have evolved, van Dokkum points out. "It's one reason why people are interested in this type of star."

More red dwarfs in elliptical galaxies

In terms of sheer numbers, stars of low mass are more dominant that hotter stars such as the Sun, which is five to 10 times more massive than a red dwarf, according to University of Sydney astronomer Scott Croom, who was not involved in the research.

Although there is no reason for red dwarf stars to have more Earth-like planets than Sun-like stars, "if there are more stars, there are more stars that can support life," Croom says.

Van Dokkum and Conroy found 80% of stars within eight elliptical galaxies 50 million and 300 million light-years away were red dwarfs. Elliptical galaxies are egg-shaped galaxies that generally evolved earlier than spiral galaxies like the Milky Way.

Major impact on theory of dark matter

"No one knew how many of these stars there were," says van Dokkum.

The results show elliptical galaxies have 20 times the number of red dwarfs as the Milky Way, which has a "major impact" for theories on galaxy evolution and calculations of the amount of dark matter required to 'balance' observations of the galaxies, says Conroy, from the Harvard-Smithsonian Center for Astrophysics in Massachusetts.

"We usually assume other galaxies look like our own. But this suggests other conditions are possible in other galaxies," he says. If red dwarfs are more abundant that astronomers realized, it may mean less dark matter is required in models that look at how star mass and galaxy rotation are linked.

Astronomers first postulated the existence of dark matter after observations of physical factors such as motion of galaxies didn't fit with galaxies' supposed mass.

This 'missing mass' became known as dark matter and is intrinsic to theories of galaxy evolution. "It's telling us elliptical galaxies have less dark matter than we originally thought and more of the mass is provided by stars," said Croom.

 

http://www.cosmosmagazine.com/news/3899/numbers-stars-universe-tripled

 

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Trillioms of Earths

Trillions of Earths. Wow, that is pretty awesome.

Now that we know that there could be trillions of Earths and the possibility of alien life forms could very well be present, I feel that I have to ask the most important scientific question that needs to be asked about this amazing discovery :

What do you think the women are like on some of these ?

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And before ANY planet gets

And before ANY planet gets close enough to the temperate (habitable) zone of a red dwarf, it most likely gets ripped apart by tidal forces...

The money's still on type V.

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Kapkao wrote:And before ANY

Kapkao wrote:

And before ANY planet gets close enough to the temperate (habitable) zone of a red dwarf, it most likely gets ripped apart by tidal forces...

The money's still on type V.

The habitable zone of a red dwarf is not that close. 

The problem is that it IS likely to be close enough for the planet to be tidally locked to the star, so that it always presents the same side toward the star.

This may restrict the habitable zone on the planet to the 'twilight' ring zone between the lit and unlit side.

Or it could result in any atmosphere freezing out on the dark side.

There are various scenarios which might avoid this problem, such as sufficiently thick atmosphere to prevent such extremes of temperature developing.

Or a large moon offsetting the tidal effect of the star.

But no 'ripping apart', that requires much closer approach.

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Yet we are so special on

Yet we are so special on this tiny little dot. And isn't nice that we cant get off this rock and actually go find a new home? What a plan.

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BobSpence1 wrote:The

BobSpence1 wrote:

The habitable zone of a red dwarf is not that close. 

The problem is that it IS likely to be close enough for the planet to be tidally locked to the star, so that it always presents the same side toward the star.

This may restrict the habitable zone on the planet to the 'twilight' ring zone between the lit and unlit side.

Or it could result in any atmosphere freezing out on the dark side.

There are various scenarios which might avoid this problem, such as sufficiently thick atmosphere to prevent such extremes of temperature developing.

Or a large moon offsetting the tidal effect of the star.

But no 'ripping apart', that requires much closer approach.

All of which reduces the odds of anything except extremophiles down to a miniscule fraction of what a planet around a yellow main sequence would have. My main point remains.

“A meritocratic society is one in which inequalities of wealth and social position solely reflect the unequal distribution of merit or skills amongst human beings, or are based upon factors beyond human control, for example luck or chance. Such a society is socially just because individuals are judged not by their gender, the colour of their skin or their religion, but according to their talents and willingness to work, or on what Martin Luther King called 'the content of their character'. By extension, social equality is unjust because it treats unequal individuals equally.” "Political Ideologies" by Andrew Heywood (2003)