After two mission extensions, the Phoenix Lander has been on the Martian surface for five months. But with an approaching winter, the Lander is already beginning to lose power, as it must now sit in five hours of freezing darkness each day. The rover will slowly lose power until the end of October when it will no longer be able to use its robotic arm. Even though its days are numbered the Phoenix Lander is still making discoveries.

For the first time in Martian history, Phoenix observed Martian snowfall. The snow observed at an altitude of about 4km above the Lander, and it appears to have vaporized before reaching the surface. The Lander has also discovered several minerals that, on Earth, would typically form in the presence of water.

Potentially, the most exciting mineral discovered is Calcium Carbonate, (CaCO₃). Calcium Carbonate is the main component of chalk, which forms in deep marine conditions from the gradual accumulation of calcite plates called coccoliths, which are shed from microorganisms called cocolithosphores. The discovery was made by the combined data of two instruments onboard the Phoenix Lander. The Thermal and Evolved Gas Analyzer,(TEGA), discovered that Carbon Dioxide was released from soil samples when exposed to high temperatures. The temperature at which the CO₂ was released is a temperature which is known to breakdown CaCO₃ into CO_2. The Microscopy, Electrochemistry and Conductivity Analyzer, (MECA), found concentration of (Ca) in the soil; this confirms the presence of CaCO3 in the soil. The presence of Calcium Carbonate does not immediately imply that chalk or microorganisms have been discovered, future tests will have to be done to determine if the CaCO₃ was formed due to ancient marine life.

Both MECA and TEGA discovered have smooth-faced layered particles which resemble clay. Clay minerals have a crystal structure which allows them to store water between Silicon and Oxygen Bonds. These bonds are relatively weak, this allows the bonds to expand and contrast depending on the water content of the environment they are in. These weak bonds also break easily along the bonding planes which give them the smooth and layered surfaces which were observed by the Lander.

Currently, Phoenix is beginning to analyze the soil found in a region called “Galloping Hessian”. This area is being explored because of its high concentration of salts. On Earth Salts are also commonly found in dried up sea beds. As the darkness and the cold settles in over the Lander its days of discovery are nearing an end. Because of the extreme conditions of the Martian winter, which loom in the Landers very near future, scientists do not think that they will be able to resurrect it when spring finally returns.

For many years astronomers have debated and speculated about the existence of intermediate mass black holes. Well an answer to the question may now be available. It looks as though one of these mysterious types of black holes has been discovered in one of the Milky Way’s globular clusters. However, this discovery may not have all the answers to the mystery.

For many years the only kinds of black holes that have been found are stellar sized ones and super massive ones. Stellar sized black holes form as a result of the death of a massive star and can range up to maybe 50 solar masses. Super massive black holes reside at the center of almost all galaxies and weigh millions if not billions of solar masses. But observations were lacking for any black holes in between these sizes.

Globular Clusters are dense formulations of stars that orbit in the outskirts of a galaxy. They reside in what is known as the halo of the galaxy. They tend to be very old and are generally no longer creating new stars. They are fairly common, we know of about 200 hundred that belong to the Milky Way.

So it was in the globular cluster known as Omega Centauri that this intermediate black hole is thought to reside. Omega Centauri is one of the largest and most massive clusters belonging to the Milky Way, and is about 17,000 light years from earth. Using NASA’s Hubble space telescope and the Gemini observatory in Chile astronomers were able to note that the stars at the center of the cluster were orbiting something with very fast speeds. These fast speeds and the absence of anything we can see suggests it is a black hole that the stars are orbiting. The astronomers then used theoretical models combined with this data to calculate the mass of this black hole at about 40,000 solar masses.

This is actually the second discovery of a medium sized black hole suggesting the first was not just a fluke and that they may be common. However, no theory currently exists to explain why they exist, that is, to explain how they could have formed. However, there existence might be important for the theory of how super massive black holes form. One of the current theories states that in an early galaxy a “seed” black hole would be needed of about this size. The black hole would feed to grow to super massive size.

However, one issue might be that Omega Centauri is not a normal globular cluster, and many theorize that it is actually the remnant of a dwarf galaxy that was gobbled up by the Milky Way. Models that compare data of galaxy mass with super massive black hole mass show that a dwarf galaxy like the one predicted for Omega Centauri would have had a black hole of this size. So this would suggest not that these intermediate black holes are the seeds for super massive ones but actually play the same role as the super massive ones on a smaller scale.

More of these intermediate sized black holes will need to be discovered before any questions about formation or purpose can be answered.

On October 6th the MESSENGER spacecraft will perform a Mercury flyby for the second time this year. MESSENGER (MErcury Surface, Space, Environment, GEochemistry and Ranging) will fly past Mercury at an altitude of 201 km while taking over 1200 images of the cratered surface.

The spacecraft made its first flyby on Jan 14th, during which it took over 1200 photos, and made several startling discoveries. Some of which demonstrated that the innermost planet is not as similar to the Earth’s Moon as once was believed. MESSENGER photographed craters which are very different from the craters on the Moon. For instance, the Caloris basin is a crater with a diameter of approximately 1545km. The floor of this crater has a surface which is more reflective than the material surrounding the crater. This is exactly opposite of the Moon, whose crater floors are darker than the surrounding material. MESSENGER also observed that Mercury’s magnetic field has changed since it was first observed by Mariner 10. MESSENGER also observed large cliffs which contain ancient faults, these faults act as a recording of the paleotectonics which occurred early in the planets history. MESSENGER also observed the mineral makeup of the planet’s surface, and discovered sodium and hydrogen in the planets exosphere.

On March 18th 2011 MESSENGER will enter Mercury’s orbit where it will gather data for an entire year. MESSENGER hopes to answer several questions. The first question: “Why is Mercury so dense?” Mercury has a density of 5.427g/cm3 which implies that the mass of mercury’s core accounts for 60% of the planets total mass. MESSENGER will gather mineralogical and compositional data to help determine why. Like on Earth, part of this core must be liquid if it is to have the dynamo necessary to generate a magnetic field.

Question 2: “What is the geologic history of Mercury?” MESSENGER will photograph and observe the planet in great detail in an attempt to better understand the processes which have shaped the planet. Specifically areas such as the faults observed on the large cliffs I described earlier. Because Mariner 10 was only able to observe 45% of the planet’s surface, MESSENGER is sure to discover more geologic splendors.

Question 3: “Is there water on Mercury?” Some of the permanently shadowed craters on Mercury’s poles contain a highly reflective material that could be ice. Mercury is the closest planet to the Sun, but it also has the largest daily temperature gradient of the terrestrial planets. Surface temperatures range from -83°C to 427°C, with the coldest temperatures recorded at the bottom of the polar craters.

MESSENGER will not begin collecting this exciting data for a couple more years, but it is sure to tease with some good photographs and interesting data while we wait. The second flyby is scheduled for next week and a third a third and final flyby is scheduled for September 28th 2009.

The solar cycle was first discovered in 1843 by Samuel Heinrich Schwabe, who noticed a periodic change from year to year in the number of sunspots. This cycle has been determined to last an average of 11 years, but it has been recorded as low as 9 years and as high as 14 years. This cycle is responsible for several space-weather phenomena such as shaping the structure of the Sun’s atmosphere, corona, and wind. The number of solar flares, mass ejections, and high energy particles are modulated by the solar cycles.

The sun is currently experiencing the lowest solar minimum observed in the last 50 years. This is also the longest lasting solar minimum ever observed, already six months longer than last cycle. A solar minimum impacts the entire solar system, and directly effects life on Earth. During a solar minimum less UV radiation reaches the Earth. This results in reduced ozone layer, because ozone is produced when UV radiation spits the O₂ molecules in the stratosphere. A smaller ozone layer means that more UV light will reach the Earth’s surface potentially causing sunburns and skin cancer.

Changes in the solar cycle could also affect the Earth’s climate. During a solar minimum less energy reaches the Earth, on an average year the Earth receives about 1366.7 W/m² during a solar maximum, and 1365.6 W/m² during the solar minimum. Some scientists argue that this difference may be too small to significantly affect the Earth’s climate. (Although it is interesting that in 2008 we experienced the largest world-wide temperature drop ever recorded in a 12 month period, not to mention Minneapolis celebrated its coldest Easter in 33 years, which is a factor of 11.) In 1991 E. Friis-Chritensen published a study which demonstrated a direct correlation between solar cycles and Land air temperature in the Northern hemisphere.

Another side effect of solar minimums is a reduced heliosphere. The heliosphere is a large magnetic bubble generated by the sun which protects the solar system from harmful cosmic rays. The Voyager spacecrafts inadvertently provided proof of the shrinking helioshpere when Voyager 2 reached the termination shock after traveling 10 AUs less than Voyager 1 had to travel in order to reach the same boundary. Because of fluctuations in solar activity Voyager 1 actually crossed the terminal shock 5 times!

By studying the Sun and its cycles, scientists are gaining a better understanding of stellar phenomena, and how it affects us here on Earth. Such knowledge will aid in the development of better climate models, and in evaluated and eliminating some of the radiation risks which would hinder future colonies on the Moon or Mars.