[LibWhacker]

The scientists calculate that such a planetary body would cross the inner solar system every 25 million years on the average

Yikes! That's almost 200 rogue, planet-sized, planet killers have zipped past us in the last 4.5 billion years.

[cripplecreek]

Speaking of nomads.

[DBrow]

A free-floating planet far from a star would have a temperature of 25K, if that. The blackbody temperature would be lower, I’m assuming some warmth from radioactive dacay, assuming the same amount of U and K as here.

I read a paper that discussed tracking long-period or one-time comets back to their origins, and they postulated the passage of a planetary mass that kicked their orbits inward.

[cpdiii]

Any planet in interstellar space will be a frozen ice ball.

[1raider1]

In keeping with the article’s theme of MAY BE... Monkeys may fly out of my ears at any moment.

[cuban leaf]

On a smaller scale, I believe they are called free radicals.

[Brookhaven]

There is a theory that the moon was formed when a planetoid struck the Earth. Both the Earth and the planetoid disintegrated, and then reformed into two bodies: the current Earth and the Moon.

The Moon is too large of a body for the Earth to have captured via gravity, which gave rise to the collision theory.

[fish hawk]

So , let me get this straight. If we were to drift away from our sun, every phase of all life on earth would be destroyed yet we are supposed to believe that myriads of no sun planets drifting around would be havens for life???

[KarlInOhio]

So much wrong is so small of article.

The scientists have proposed that these life-bearing planets

Has any evidence been presented at all that they are life-bearing? So far we are 0-for-2 on detection of microscopic life on extraterrestrial bodies (moon and Mars) and zero for a lot more for detection of macroscopic life where we get close enough to various planets and moons to take detailed pictures of them.

originated in the early Universe within a few million years of the Big Bang,

For a planet to be anything other than a gas giant like Jupiter, there have to be elements heavier than hydrogen and helium. I don't know when the first stars when supernova, but the planets would have had to have formed after than to have any chance to have carbon, nitrogen, oxygen or even heavier elements like silicon or iron in them.

and that they make up most of the so-called “missing mass” of galaxies.

I've seen estimates that up to 90% of the mass is "missing". Since Jupiter is about one one-thousandth of the mass of the sun, that means you would need ten thousand missing Jupiter size planets for every sun sized star to account for the mass this way.

and during each transit, zodiacal dust, including a component of the solar system’s living cells,

What living cells? Have we ever found even one extraterrestrial cell? Just one? Then why is it assumed that they exist?

[UCANSEE2]

“The scientists have proposed that these life-bearing planets originated in the early Universe within a few million years of the Big Bang, and that they make up most of the so-called “missing mass” of galaxies.”

Goodbye ‘dark matter’, Hello ‘missing mass’.

[treetopsandroofs]

“Space 1999” called it first.

Each week, our moon went zipping all over the galaxy.

[Pontiac]

The scientists have proposed that these life-bearing planets originated in the early Universe within a few million years of the Big Bang, and that they make up most of the so-called “missing mass” of galaxies. The scientists calculate that such a planetary body would cross the inner solar system every 25 million years on the average and during each transit, zodiacal dust, including a component of the solar system’s living cells, becomes implanted at its surface.

These components would have been sterilized by the solar wind. Any DNA that would have existed in what would have been living cells that may have survived the trip out of the atmosphere would be blasted in to incoherent and inert dust by the solar wind within short period of time unless shielded by being buried very deep inside a very large rock.

Any rock large enough to be shielding for life would be superheated by impacting a wandering planet again destroying that life.

The idea that a wandering lifeless planet could pick up life by drifting by a life bearing planet seems to me pretty far fetched.

[dfwgator]

"My God, It's full of planets."

[yefragetuwrabrumuy]

I truly doubt that many such rogue planets are still about, at least within the galaxies. Galaxies are dynamic things, with all kinds of tidal forces at several levels.

To start with, why is the vast majority of the Milky Way galaxy spinning in the same direction? And imagine how much force is needed to keep it from flying apart.

Yet things are constantly changing in the galaxy. Sooner or later, over the course of 14.5 billion years, rogues are going to meet up with somebody.

[PapaBear3625]

Is springer.com supposed to be a reliable source for science articles?

[ichabod1]

There are thirteen other planets with highly evolved dominant species like H. Sapiens. Some of them have evolved more along the lines of birds. One is reptilian-based.

[hosepipe]

There you go.. get a PHD and your bullshit instantly becomes defecation...
Your dreck becomes interesting attributes of a fine wine..

Carl Sagan said life had to happen somewhere first....
Why not Here..

If it did, Why?... was it planted?.. Is there some adjacent agenda?..
I am thinking of a wild concept..
http://www.youtube.com/watch?v=G_DV54ddNHE