Mercury: Messenger Orbital Data Confirm Theories, Reveal Surprises

                    On March 18, 2011, the MESSENGER spacecraft entered orbit around Mercury to become that planet's first orbiter. The spacecraft's instruments are making a complete reconnaissance of the planet's geochemistry, geophysics, geologic history, atmosphere, magnetosphere, and plasma environment. MESSENGER is providing a wealth of new information and some surprises. For instance, Mercury's surface composition differs from that expected for the innermost of the terrestrial planets, and Mercury's magnetic field has a north-south asymmetry that affects interaction of the planet's surface with charged particles from the solar wind.

                   

Tens of thousands of images reveal major features on the planet in high resolution for the first time. Measurements of the chemical composition of the planet's surface are providing important clues to the origin of the planet and its geological history. Maps of the planet's topography and magnetic field are offering new evidence on Mercury's interior dynamical processes. And scientists now know that bursts of energetic particles in Mercury's magnetosphere are a continuing product of the interaction of Mercury's magnetic field with the solar wind.

                   "MESSENGER has passed a number of milestones just this week," offers MESSENGER principal investigator Sean Solomon of the Carnegie Institution. "We completed our first perihelion passage from orbit on Sunday, our first Mercury year in orbit on Monday, our first superior solar conjunction from orbit on Tuesday, and our first orbit-correction maneuver on Wednesday. Those milestones provide important context to the continuing feast of new observations that MESSENGER has been sending home on nearly a daily basis."

The Surface in Detail

                  Images obtained with MESSENGER's Mercury Dual Imaging System (MDIS) are being combined into maps for the first global look at the planet under optimal viewing conditions. New images of areas near Mercury's north pole orbital show that region hosts one of the largest expanses of volcanic plains deposits on the planet, with thicknesses of up to several kilometers. The broad expanses of plains confirm that volcanism shaped much of Mercury's crust and continued through much of Mercury's history, despite an overall contractional stress state that tended to inhibit the extrusion of volcanic material onto the surface.

               Among the fascinating features seen in flyby images of Mercury were bright, patchy deposits on some crater floors, but they remained a curiosity. New targeted MDIS observations reveal these patchy deposits to be clusters of rimless, irregular pits with horizontal dimension from hundreds of meters to several kilometers. These pits are often surrounded by diffuse halos of higher-reflectance material, and they are found associated with central peaks, peak rings, and rims of craters.

"The etched appearance of these landforms is unlike anything we've seen before on Mercury or the Moon," says Brett Denevi, a staff scientist at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md., and a member of the MESSENGER imaging team. "We are still debating their origin, but they appear to have a relatively young age and may suggest a more abundant than expected volatile component in Mercury's crust."

The Surface Composition

                 The X-Ray Spectrometer (XRS) has made several important discoveries since orbit insertion. The magnesium/silicon, aluminum/silicon, and calcium/silicon ratios averaged over large areas of the planet's surface show that, unlike the surface of the Moon, Mercury's surface is not dominated by feldspar-rich rocks. XRS observations have also revealed substantial amounts of sulfur at Mercury's surface, lending support to suggestions from ground-based observations that sulfide minerals are present. This discovery suggests that Mercury's original building blocks may have been less oxidized than those that formed the other terrestrial planets and could be key to understanding the nature of volcanism on Mercury.

              MESSENGER's Gamma-Ray and Neutron Spectrometer detected the decay of radioactive isotopes of potassium and thorium, and researchers have determined the bulk abundances of these elements. "The abundance of potassium rules out some prior theories for Mercury's composition and origin," says Larry Nittler, a staff scientist at the Carnegie Institution. "Moreover, the inferred ratio of potassium to thorium is similar to that of other terrestrial planets, suggesting that Mercury is not highly depleted in volatiles, contrary to some prior ideas about its origin."

Mercury's Topography and Magnetic Field

                  MESSENGER's Mercury Laser Altimeter has been mapping the topography of Mercury's northern hemisphere in detail. The north polar region, for instance, is a broad area of low elevations. The overall topographic height range seen to date exceeds 9 kilometers (5.5 miles).

Previous Earth-based radar images showed that around Mercury's north and south poles are deposits thought to consist of water ice and perhaps other ices preserved on cold, permanently shadowed floors of high-latitude impact craters. MESSENGER's altimeter is measuring the floor depths of craters near the north pole. The depths of craters with polar deposits support the idea that these areas are in permanent shadow.

                   The geometry of Mercury's internal magnetic field can potentially allow the rejection of some theories for how the field is generated. The spacecraft found that Mercury's magnetic equator is well north of the planet's geographic equator. The best-fitting internal dipole magnetic field is located about 0.2 Mercury radii, or 480 km (298 miles), northward of the planet's center. The dynamo mechanism responsible for generating the planet's magnetic field therefore has a strong north-south asymmetry.

As a result of this north-south asymmetry, the geometry of magnetic field lines is different in Mercury's north and south polar regions. In particular, the magnetic "polar cap" where field lines are open to the interplanetary medium is much larger near the south pole. This geometry implies that the south polar region is much more exposed than the north to charged particles heated and accelerated by the solar wind. The impact of those charged particles onto Mercury's surface contributes both to the generation of the planet's tenuous atmosphere and to the "space weathering" of surface materials, both of which should have a north-south asymmetry.

Energetic Particles at Mercury

              One of the major discoveries made by Mariner 10 flybys of Mercury in 1974 were bursts of energetic particles in Mercury's Earth-like magnetosphere. Four bursts of particles were observed on the first flyby, so it was puzzling that no such events were detected by MESSENGER during any of its three flybys.

          With MESSENGER now in near-polar orbit about Mercury, energetic events are being seen almost like clockwork, remarked MESSENGER Project Scientist Ralph McNutt, of APL. "While varying in strength and distribution, bursts of energetic electrons -- with energies from 10 kiloelectron volts (keV) to more than 200 keV -- have been seen in most orbits since orbit insertion," McNutt said. "The Energetic Particle Spectrometer has shown these events to be electrons rather than energetic ions, and to occur at moderate latitudes. The latitudinal location is entirely consistent with the events seen by Mariner 10."

           With Mercury's smaller magnetosphere and with the lack of a substantial atmosphere, the generation and distribution of energetic electrons differ from those at Earth. One candidate mechanism for their generation is the formation of a "double layer," a plasma structure with large electric fields along the local magnetic field. Another is induction brought about by rapid changes in the magnetic field, a process that follows the principle used in generators on Earth to produce electric power. The mechanisms at work will be the studied over the coming months.

           "We are assembling a global overview of the nature and workings of Mercury for the first time," remarked Solomon, "and many of our earlier ideas are being cast aside as new observations lead to new insights. Our primary mission has another three Mercury years to run, and we can expect more surprises as our Solar System's innermost planet reveals its long-held secrets."

Cancer death rates continue drop: report

CHICAGO (Reuters) – U.S. cancer death rates are continuing to fall, but not all segments of the population are benefiting, the American Cancer Society said Friday.

Overall, the group predicts 1,596,670 new cancer cases in the United States and 571,950 deaths in 2011.

Death rates for all cancer types fell by 1.9 percent a year from 2001 to 2007 in men and by 1.5 percent a year in women from 2002 through 2007.

Steady overall declines in cancer death rates have meant about 898,000 who would have died prematurely from cancer in the past 17 years did not, the organization said.

Americans with the least education are more than twice as likely to die from cancer as those with the most education, according to the group's annual cancer report.

Death rates for all cancer types have fallen in all racial and ethnic groups among both men and women since 1998 with the exception of American Indian/Alaska Native women, among whom rates were stable.

Black and Hispanic men have had the largest annual decreases in cancer death rates since 1998, falling by 2.6 percent among blacks and 2.5 percent among Hispanics.

New cases of lung cancer among women fell after rising steadily since the 1930s. The decline comes more than a decade after lung cancer rates in men started dropping and reflects differences in smoking trends among U.S. men and women, who took up smoking later in the last century than men.

Lung cancer is expected to account for 26 percent of all cancer deaths among women in 2011 and remains the No. 1 cancer killer of both men and women in the United States.

Breast cancer comes in No. 2 for women. Prostate cancer is the second most common killer of men, and colon cancer is the third-leading cause of cancer deaths for both sexes.

These four cancers account for almost half the total cancer deaths among men and women.

Cancer rates vary considerably among racial and ethnic groups. For all cancer types, black men have a 14 percent higher rate of new cases and a 33 percent higher death rate than white men, while black women have a 6 percent lower rate of new cancer cases and a 17 percent higher death rate than white women.

The report found cancer rates in the least educated were 2.6 times higher than in the most educated. This was most pronounced in lung cancer, reflecting higher smoking rates among those with less education.

Thirty-one percent of men with 12 or fewer years of education are smokers, compared with 12 percent of college graduates and 5 percent of men with advanced degrees.

(Editing by Todd Eastham)

Capital One to buy ING's U.S. online bank for $9 billion

AMSTERDAM/CHARLOTTE, North Carolina (Reuters) – Capital One Financial Corp plans to buy ING Groep NV's U.S. online bank for $9 billion in cash and stock, freeing the Dutch bank to repay bailout funds and sever its state ties.
ING is in the throes of a wrenching restructuring, forced on it as a condition of a 10-billion-euro state bailout during the 2008 financial crisis.
The European Commission and ING agreed on a restructuring plan in late 2009, the most surprising part of which was a mandate that ING sell its U.S. online banking operations.
But ING has made clear it wants to be freed of its state shackles, as that would lift restrictions on making acquisitions and give it more flexibility on pricing and allow it to compete more easily.
The Capital One deal caps a long list of divestments by the Dutch bancassurer.
It has raised at least 5.4 billion euros from the sale of assets including its Asian private banking assets and insurance operations in Canada, Taiwan, Australia and Chile, and agreed to sell most of its real estate investment management operations to CB Richard Ellis and other parties in a deal worth $1.1 billion.
But it still must complete the sale of ING Direct USA, and spin off its U.S. European and Asian insurance operations in two separate IPOs next year. It also plans to divest its Latin American insurance business in the next few months.
Last month, ING paid 3 billion euros to the Dutch state, which included a 50 percent premium, and said at the time that it would repay the remaining 3 billion euros by May 2012.
With the proceeds from selling its U.S. unit to Capital One, ING could repay the remainder sooner, but Chief Executive Jan Hommen said any decision on early repayment could be dictated by the outcome of a European court case, with a hearing set for next month.
ING and the Dutch state had objected to European Commission calculations on how much state aid it has received. If ING wins the case, that could mean it has to divest less business.
Hommen also dismissed any talk of going on the prowl for acquisitions once the state has been repaid in full.
"I'm not looking to do acquisitions," he told reporters in a conference call.
"We still are in the process of separating our banking and insurance operations, to bring the IPOs to market next year ... we have a lot of work to do."
Lemer Salah, an analyst at SNS Securities, said that he expected ING to focus on expanding its retail banking operations in Europe and emerging Europe once the restrictions are lifted.
"Once they've repaid the state they can really expand their retail operations, through M&A or growth," he said.
LEAPFROG
ING will receive a 9.9 percent stake in Capital One as part of the deal, with a six-month lock-up on holding the shares, and will have the right to name a director to the U.S. bank's board.
Following the acquisition, Capital One -- a McLean, Virginia-based bank which is best known for its credit card unit -- will leapfrog two places up the rankings of the largest U.S. banks to become the nation's seventh-largest bank by assets, according to SNL Financial, a financial services data firm.
The deal is the latest step in Capital One's efforts to transform itself from its credit card lending roots.
"Capital One is picking up market share at what they feel are reasonable rates," said Matt McCormick, portfolio manager with Bahl & Gaynor Investment Counsel. "They're thinking that now's the time to pick up market share by acquisition. It's a risk, but it's a calculated risk."
The U.S. bank will pay $6.2 billion in cash and $2.8 billion in stock. It will raise $2 billion in new capital and will offer debt of about $3.7 billion to help finance the deal, which is expected to close around the end of the year.
According to SNL Financial, ING Direct USA is the 20th-largest U.S. bank. As of March 31, Capital One had $199.3 billion of assets.
Capital One said it expects to realize "modest" cost-savings of $90 million from the deal, and funding savings of $200 million annually. It said the deal would be accretive to earnings per share in 2012 and would result in "mid-single digit accretion" in 2013.
Shares of Capital One closed up 2.4 percent at $49 on Thursday.
Morgan Stanley, Barclays Capital and Centerview Partners LLC acted as financial advisers to Capital One and Wachtell, Lipton, Rosen and Katz, Mayer Brown and Loyens & Loeff acted as legal advisers. Deutsche Bank advised ING.
(Additional reporting by Maria Aspan and Ben Berkowitz in New York; Editing by Jon Loades-Carter)