Astronomers have concluded that the stars in the Milky Way must average at least one planet per star.

Billions and billions! Astronomers have concluded that the stars in the Milky Way must average at least one planet per star. More importantly, the data says the galaxy should have billions of habitable planets.

[According to astronomer Uffe Gråe Jørgensen], a statistical analysis … shows that out of the Milky Way’s 100 billion stars, there are about 10 billion stars with planets in the habitable zone. This means that there may be billions of habitable planets in the Milky Way.

The most distant supernova discovered so far.

The most distant supernova discovered so far.

SN Primo is the farthest Type Ia supernova whose distance has been confirmed through spectroscopic observations. The supernova was discovered as part of a three-year Hubble program to survey faraway Type Ia supernovae, enabling searches for this special class of stellar explosion at greater distances than previously possible. The remote supernovae will help astronomers determine whether the exploding stars remain dependable distance markers across vast distances of space in an epoch when the cosmos was only one-third its current age of 13.7 billion years.

The National Radio Astronomy Observatory (NRAO) has renamed the thirty-one year old Very Large Array (VLA) after Karl Jansky, the man who invented radio astronomy.

A fitting honor: The National Radio Astronomy Observatory (NRAO) has renamed the recently upgraded thirty-one year old Very Large Array (VLA) after Karl Jansky, the man who invented radio astronomy.

Karl Guthe Jansky joined Bell Telephone Laboratories in New Jersey in 1928, immediately after receiving his undergraduate degree in physics. He was assigned the task of studying radio waves that interfered with the recently-opened transatlantic radiotelephone service. After designing and building advanced, specialized equipment, he made observations over the entire year of 1932 that allowed him to identify thunderstorms as major sources of radio interference, along with a much weaker, unidentified radio source. Careful study of this “strange hiss-type static” led to the conclusion that the radio waves originated from beyond our Solar System, and indeed came from the center of our Milky Way Galaxy.

His discovery was reported on the front page of the New York Times on May 5, 1933, and published in professional journals. Jansky thus opened an entirely new “window” on the Universe. Astronomers previously had been confined to observing those wavelengths of light that our eyes can see. “This discovery was like suddenly being able to see green light for the first time when we could only see blue before,” said Lo.

After 16 years in space, NASA’s Rossi X-ray Timing Explorer (RXTE) has been shut down

After 16 years in space, NASA’s Rossi X-ray Timing Explorer (RXTE) has finally been shut down.

RXTE far exceeded its original science goals and leaves astronomers with a scientific bounty for years to come. Data from the mission have resulted in more than 2,200 papers in refereed journals, 92 doctoral theses, and more than 1,000 rapid notifications alerting astronomers around the globe to new astronomical activity.

“The spacecraft and its instruments had been showing their age, and in the end RXTE had accomplished everything we put it up there to do, and much more,” said Tod Strohmayer, RXTE project scientist at Goddard. The decision to decommission RXTE followed the recommendations of a 2010 review board tasked to evaluate and rank each of NASA’s operating astrophysics missions.

The National Science Foundation has declined until 2020 to commit to funding a giant American-built ground-based telescope

Bad news for American astronomy: The National Science Foundation has declined until 2020 to commit to any funding for either one of the two giant American-built ground-based telescopes.

For nearly a decade now, two university consortia in the United States have been in a race to build two ground-based telescopes that would be several times bigger than today’s biggest optical telescope. One group—led by the University of California—plans to build the Thirty Meter Telescope (TMT) in Hawaii. The other team—led by Carnegie Observatories, the University of Arizona, and other institutions—is developing a 28-meter behemoth named the Giant Magellan Telescope (GMT), which would be built in Chile. Over the past few years, both teams have raised tens of millions of dollars toward the billion-dollar-plus projects in the hope that the U.S. National Science Foundation (NSF) would come up with the balance.

But now, it turns out, neither project has a chance of receiving any significant funding from NSF for at least another decade. In a solicitation posted by NSF last week, the agency indicated that it does not expect to fund the building of any giant segmented mirror telescopes—that is, TMT or GMT—until the beginning of the 2020s. According to the solicitation, all that NSF can provide right now is $1.25 million over 5 years for the development of a public-private partnership plan that could eventually lead to the building of a large telescope, should NSF be in a position to fund such a telescope sometime in the next decade.

I suspect the NSF’s unwillingness to fund this project at this time is directly related to the budget crisis in Washington. Though the NSF got slightly more money in 2012 than in 2011, that money is all accounted for by other projects. There is no margin for anything new that will be as expensive (in the billions) as these giant telescopes will be.

Want to see an asteroid eclipse a star?

transit of Betelgeuse

On January 2, 2012, an asteroid is going to transit across the face of Betelgeuse. And if you live in Europe, own a very sensitive telescope, look close and don’t blink, you might be able to see it!

This is all according to a preprint paper published today on the Los Alamos astro-ph preprint website, written by scientist Costantino Sigismondi of the Galileo Ferraris Institute and International Center for Relativistic Astrophysics in Rome. You can download the paper here [pdf].

The transit itself will only last 3.6 seconds, and will only be visible along a narrow swath crossing southern India and moving across the Middle East, through parts of Italy, France, and the southwestern most tips of England and Ireland. A map of this path is below the fold.
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A Sun-like Star with Three Sub-Neptune Exoplanets and Two Earth-size Candidates

Want to read the actual paper, “A Sun-like star with three sub-Neptune exoplanets and two Earth-size candidates,” describing the discovery announced yesterday of two Earth-sized planet? You can download it here.

The paper’s closing paragraph sums the discovery up nicely:

A striking feature of the Kepler-20 planetary system is the presence of Earth-size rocky planet candidates interspersed between volatile-rich sub-Neptunes at smaller and larger orbital semi-major axes, as also seen in Kepler candidate multi-planet systems. Assuming that both [Kepler-20e] and [Kepler-20f] are planets, the distribution of the Kepler-20 planets in orbital order is as follows: Kepler-20b (3.7 days, 1.9 Earth radii), [Kepler-20e] (6.1 days, 0.9 Earth radii), Kepler-20c (10.9 days, 3.1 Earth radii), [Kepler-20f] (19.6 days, 1.0 Earth radii), and Kepler-20d (77.6 days, 2.8 Earth radii). Given the radii and irradiation fluxes of the two Earth-size planet candidates, they would not retain gas envelopes. The first, second, and fourth planets have high densities indicative of solid planets, while the other two planets have low densities requiring significant volatile content. The volatile-rich third planet, Kepler-20c dominates the inner part of the Kepler-20 system, by holding much more mass than the other three inner planets put together. In the Solar System, the terrestrial planets, gas-giants, and ice giants are neatly segregated in regions with increasing distance from the sun. Planet formation theories were developed to retrodict these Solar System composition trends. In the Kepler-20 system, the locations of the low-density sub-Neptunes that are rich in water and/or gas, and the Earth-size planet candidates does not exhibit a clean ordering with orbital period, challenging the conventional planet formation paradigm. In situ assembly may form multi-planet systems with close-in hot-Neptunes and super-Earths, provided the initial protoplanetary disk contained massive amounts of solids (∼ 50–100 Earth masses) within 1AU of the star.

First Earth-sized planets found

Big news: The first Earth-sized planets have been found by Kepler.

The two planets, dubbed Kepler-20e and 20f, are the smallest planets found to date. They have diameters of 6,900 miles and 8,200 miles – equivalent to 0.87 times Earth (slightly smaller than Venus) and 1.03 times Earth. These worlds are expected to have rocky compositions, so their masses should be less than 1.7 and 3 times Earth’s.

Both worlds circle Kepler-20: a G-type star slightly cooler than the Sun and located 950 light-years from Earth. (It would take the space shuttle 36 million years to travel to Kepler-20.) Kepler-20e orbits every 6.1 days at a distance of 4.7 million miles. Kepler-20f orbits every 19.6 days at a distance of 10.3 million miles. Due to their tight orbits, they are heated to temperatures of 1,400 degrees Fahrenheit and 800 degrees F.

Once again, this is only the beginning. The announcement of an Earth in the habitable zone is only a matter of months away.

Former astronaut John Grunsfeld is to take over NASA’s science post from Ed Weiler

Excellent choice: Former astronaut John Grunsfeld has been picked to take over NASA’s chief science post from Ed Weiler.

Not only is Grunsfeld an excellent choice, his experience as an astronaut repairing Hubble will help improve relations between the science and manned space programs. In the past, scientists have often argued against manned space, trying to get that money for their unmanned research probes. Instead, when manned space got cut, so did science, and no one won. Grunsfeld’s leadership I think will forestall these short-sighted complaints.

The supernova of a generation

The supernova of a generation.

There will be a slew of stories about this in the next few days. The important takeaways are as follows:

  • After almost a half century, astronomers have finally proven the theory that type Ia supernovae come from the explosion of a white dwarf star, overloaded with material sucked from its binary companion.
  • The prediction that the companion would be a red giant star, however, has turned out to be wrong. At the same time, astronomers still do not know what kind of star it was in this particular case.
  • With this new knowledge astronomers will have a better chance of identifying type Ia supernovae, before they go boom.
  • Finally, type Ia supernovae are used to measure the expansion rate of the universe, and thus were the key to discovering dark energy. By better understanding how these supernovae occur, cosmologists will be better able to constrain what they know about dark energy.

An experiment designed to mimic the dynamo at the Earth’s core is about to be turned on.

Mad scientists at their best! An experiment designed to mimic the dynamo at the Earth’s core is about to be turned on.

Ten years in the making, the US$2-million project is nearly ready for its inaugural run. Early next year, the sphere will begin whirling around while loaded with 13,000 kilograms of molten sodium heated to around 105 °C. Researchers hope that the churning, electrically conducting fluid will generate a self-sustaining electromagnetic field that can be poked, prodded and coaxed for clues about Earth’s dynamo, which is generated by the movement of liquid iron in the outer core. If it works, it will be the first time that an experiment that mirrors the configuration of Earth’s interior has managed to recreate such a phenomenon.

This is a really very cool experiment, as we really do not have a good understanding of how planetary magnetic fields are produced.

Two newly discovered supermassive black holes weigh in as the heaviest known

Two newly discovered supermassive black holes weigh in as the heaviest known.

One of the newly discovered black holes is 9.7 billion solar masses and is located in the elliptical galaxy NGC 3842, which is the brightest galaxy in the Leo cluster of galaxies that sits 320 million light years away in the direction of the constellation Leo. The second is as large or larger and sits in the elliptical galaxy NGC 4889, which is the brightest galaxy in the Coma cluster about 336 million light years from Earth in the direction of the constellation Coma Berenices.

It is believed that these heavy supermassive black holes are the kind that produced quasars in the early universe.

Voyager 1 at the edge

This week the American Geophysical Union (AGU) is having its annual fall meeting in San Francisco. Due to the wonders of technology, they are now making their press conferences available to reporters on line. Thus, I will be posting periodic updates after each conference. This will allow my readers to get a heads up on stories they will be seeing in the mainstream press in the next few hours.

Right now they are wrapping up a press conference from the team of the Voyager 1 spacecraft, in which they have described the spacecraft’s status.
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