UFO'S of UAP'S, ASTRONOMIE, RUIMTEVAART, ARCHEOLOGIE, OUDHEIDKUNDE, SF-SNUFJES EN ANDERE ESOTERISCHE WETENSCHAPPEN

IN BRIEF

Astronomers from the University of Texas have pinpointed the location of a possible Earth-like planet not far from here. It has two identified exoplanets, and a possible third one may be a little like our own.

“WE FOUND ANOTHER ONE”

There are many reasons to explore the cosmos; however, one of the most intriguing reasons is to find another planet with life. We send out probes and we look towards the sky with our telescopes and radar dishes, all in the hope of finding another Earth. We have discovered many planets to date that seem to be rather Earth-like, and we are finding more.

Case in point, astronomers from the University of Texas have pinpointed the location of a possible Earth-like planet not far from here. Of course, it could also be rather unEarth-like. Hopefully, additional research will give us a definitive answer soon.

Gliese 832 is a red dwarf sun half the mass and radius of our own star. It is 16 light-years away from our solar system, and it has two identified exoplanets…and a possible third just cropped up.

The paper discussing the finding, published in arXiv, says that the potential Earth-like planet may exist between the two exoplanets, Gliese 832B and Gliese 832C.

Gliese 832B is a gas giant that is 0.64 the mass of Jupiter, and it orbits its star at 3.5 AU. The other planet, Gliese 832C, is a rocky world about 5 times as massive as Earth, and it orbits the star at a very close 0.16 AU. Both cannot harbor life as we know it, as 832B is a gas giant and 832C is too close to the star.

BASED ON A HUNCH

The already discovered planets were seen because of the radial velocity technique, which measures the gravitational effect of the planets on the star. The astronomers had a hunch that another planet may exist between the vast distance of 832B and 832C. They reexamined the data, and concluded that another planet may exist between them.

The newly discovered planet is still hypothetical at this point, and the researchers put its mass at between 1 and 15 Earth masses (yeah kind of a big margin there), and its orbit is between 0.25 to 2.0 AU from Gliese 382 (1 AU is roughly the distance from Earth to the Sun).

Conclusions such as these are not made definitively, but only so that planet hunters and telescopes such as Kepler know specifically where to look.

Most of the cosmic rays arriving at Earth from our galaxy come from nearby clusters of massive stars, according to new observations from the Cosmic Ray Isotope Spectrometer (CRIS), an instrument aboard NASA’s Advanced Composition Explorer (ACE) spacecraft.

Morgan-Keenan spectral classification of stars. — Galactic cosmic rays are thought to come from clusters of massive stars called OB associations, named for the blue and blue-white light they emit. Our Sun in a G star in this classification scheme. (Image: Wikimedia Commons)

The distance between the galactic cosmic rays’ point of origin and Earth is limited by the survival of a very rare type of cosmic ray that acts like a tiny clock. The cosmic ray is a radioactive isotope of iron, ⁶⁰Fe, which has a half life of 2.6 million years. In that time, half of these iron nuclei decay into other elements.

In the 17 years CRIS has been in space, it detected about 300,000 galactic cosmic-ray nuclei of ordinary iron, but just 15 of the radioactive ⁶⁰Fe .

“Our detection of radioactive cosmic-ray iron nuclei is a smoking gun indicating that there has been a supernova in the last few million years in our neighborhood of the galaxy,” said Robert Binns, research professor of physics in Arts & Sciences at Washington University in St. Louis, and lead author on the paper published online in Science April 21.

What are cosmic rays?

Cosmic rays were discovered before World War I but named in the 1920s by the famous physicist Robert Millikin, who called them “rays” because he thought they were a form of high-energy electromagnetic radiation.

But in the early 1930s, Arthur Compton, later chancellor of Washington University in St. Louis, organized a collaboration of eight research groups to measure cosmic-ray intensity at 69 locations around the Earth. Variations in the intensity with magnetic latitude showed that cosmic rays were deflected by the Earth’s magnetic field, and must therefore be charged particles (the nuclei of atoms stripped of their electrons) rather than electromagnetic radiation.

Of these nuclei, 90 percent are hydrogen nuclei (protons), 9 percent are helium nuclei and only one percent are the nuclei of heavier elements. But that one percent provides the best clues to how the particles are created.

Although energetic particles coming from our sun are sometimes called cosmic rays, astrophysicists prefer to call these comparatively low energy particles SEPs, or solar energetic particles.

They reserve the term “cosmic ray” for particles coming from outside our solar system, either from our galaxy or beyond. These fall into two groups based on their energies.

Most of those now thought to be created by supernova explosions in or near our galaxy have energies of 10⁹ and 10¹⁰ eV — although they can have energies as high as 10¹⁵ or higher — and a flux of about one per second per square centimeter. (The molecules in our atmosphere have kinetic energies of about 0.03 eV.)

But there are also cosmic-ray nuclei that are several billion times more energetic, and much rarer. They have energies of 10¹⁹ to 10²⁰ eV and fluxes more like one per square kilometer per century. The source of these extremely rare particles is still unknown.

“The new data also show the source of galactic cosmic rays is nearby clusters of massive stars, where supernova explosions occur every few million years,” said Martin Israel, professor of physics at Washington University and a co-author on the paper.

The radioactive iron is believed to be produced in core-collapse supernovae, violent explosions that mark the death of massive stars, which occur primarily in clusters of massive stars called OB associations.

There are more than 20 such associations close enough to Earth to be the source of the cosmic rays, including subgroups of the nearby Scorpius and Centaurus constellations, such as Upper Scorpius (83 stars), Upper Centaurus Lupus (134 stars) and Lower Centaurus Crux (97 stars). Because of their size and proximity, these are the likely sources of the radioactive iron nuclei CRIS detected, the scientists said.

An incriminating timeline

The ⁶⁰Fe results add to a growing body of evidence that galactic cosmic rays are created and accelerated in OB associations.

Earlier CRIS measurements of nickel and cobalt isotopes show there must be a delay of at least 100,000 years between creation and acceleration of galactic cosmic-ray nuclei, Binns said.

This time lag also means that the nuclei synthesized in a supernova are not accelerated by that supernova, but by the shock wave from a second nearby supernova, Israel said, one that occurs quickly enough that a substantial fraction of the ⁶⁰Fe from the first supernova has not yet decayed.

Together, these time constraints mean the second supernova must occur between 100,000 and a few million years after the first supernova. Clusters of massive stars are one of the few places in the universe where supernovae occur often enough, and close enough together, to bring this off.

“So our observation of ⁶⁰Fe lends support to the emerging model of cosmic-ray origin in OB associations,” Israel said.

Corroborating evidence?

Although the supernovae in a nearby OB association that created the ⁶⁰Fe CRIS observed happened long before people were around to observe suddenly brightening stars (novae), they also may have left traces in Earth’s oceans and on the moon.

In 1999, astrophysicists proposed that a supernova explosion in Scorpius might explain the presence of excessive radioactive iron in 2.2 million-year-old ocean crust. Two research papers recently published in Nature bolster this case. One research group examined ⁶⁰Fe deposition worldwide, and argued that there might have been a series of supernova explosions, not just one. The other simulated by computer the evolution of Scorpius-Centaurus association in an attempt to nail down the sources of the ⁶⁰Fe.

Lunar samples also show elevated levels of ⁶⁰Fe consistent with supernova debris arriving at the moon about 2 million years ago. And here, too, there is recent corroboration. A paper just published in Physical Review Letters describes an analysis of nine core samples brought back by the Apollo crews.

In fact, you could say there has been a virtual supernova of ⁶⁰Fe research.