Another Extrasolar Planet

The picture above is the first picture of a planet (top-left) orbiting a sun-like star. It was taken by the 270-inch diameter Gemini North Telescope, located on Mauna Kea in Hawaii.

The star, 1RXS J160929.1-210524, is located in the Scorpius constellation, 500 light-years away from Earth. This star is very similar to our Sun, but is younger.

However, more interesting is the planet that is orbiting that star. This planet has a mass 7 to 12 times larger than Jupiter, the largest planet in our solar system. It also lies 30 billion miles (48 million km) away from the star, 330 times the distance from the Earth to the Sun.

Yet, the importance of this discovery is not just in the comparison of this system to our own system. It is only the third candidate planet outside our solar system that has been photographed by us. The astronomers who have made this discovery are checking if the planet is moving with its star through space, confirming that is an actual planet. This may take many years.

Image: Gemini Observatory

Leap Year

If you haven't looked at the calendar today, it's February 29, 2008. February 29 only occurs on leap years, and 2008 happens to be one. So what exactly is a leap year?

Basically, a leap year is a year containing one extra day. It supposedly is every year evenly divisible by 4, but it's more complex than that.

A tropical year, or solar year, is approxima

tely 6 hours more than 365 days. 6 hours is a quarter of a day, so one year is approximately 365.25 days long. Therefore adding one more day to the calendar every 4 years would make sense, making an average year 365.25 days long, and that's exactly what the Julian calendar does. But notice that a solar year is only approximately 6 hours more than 365 days; it's actually a bit shorter, about 365.24237

4 days long, and increasing. So to better approximate the length of the year, a better system was developed.

The Gregorian calendar is the most widely used one in the world. It was decreed by Pope Gregory XIII in 1582 to make sure Easter and the Vernal Equinox would fall at the same time. It modified the Julian calendar with a new rule. Leap years are years exactly divisible by 4, except years that are exactly divisible by 100, but centurial years exactly divisible by 400 are still leap years. What that means is that the 

year 1900 was not a leap year, but 2000 was. While in the Julian calendar, both 1900 and 2000 were leap years. The Gregorian calendar results in a better average year: 365.2425 days long, which gives a more accurate approximation.

Update: Google has made a Google Doodle for the Leap Year. It shows a frog "leaping" instead of the l in Google.

Forecasting Solar Storms

A new way to predict solar storms has been developed by the physicist Arik Posner, using the SOlar and Heliospheric Observatory (SOHO), and can give as much as one hour advanced warning for astronauts in space to seek shelter. This is a very important breakthrough, especially for astronauts, because these dangerous storms had been very hard predict before.

Solar radiation storms are bursts of electrons, protons, and heavy ions accelerated by massive explosions on our Sun. Our Earth's atmosphere and magnetic field protects us from these massive bursts; even astronauts in Earth orbit, the magnetic field reaches far enough to protect them. But when, astronauts leave this field, like on future trips to the Moon and Mars, they are in danger; neither of these objects contains a global magnetic field. However, a one hour warning can be very beneficial, providing enough time to seek proper shelter until the threat is over. This warning can also help satellites as well. Solar radiation storms can cause the satellite's computers to malfunction and reboot, but prior warning can allow a safe mode to be turned on.

The most dangerous particles are ions, atoms that have lost one or more of their electrons. They can damage tissue, break strands of DNA, and lead to diseases like cancer. Posner's way to detect these are to use electrons which are always detected before the ions. This had been previously known, but Posner used this information to forecast solar storms.

In all storms, a mix of electrons, ions, and protons are released, and the electrons, being the smallest particles, reach Earth first. Posner discovered that by measuring the "rise time and intensity of the initial electron surge," he could be able to tell how many ions are arriving and when.

Posner came to this conclusion by using the COSTEP (COmprehensive SupraThermal and Energetic Particle analyzer) on the SOHO spacecraft. This device counts the particles coming from the sun and measures their energies. Posner constructed a predictive matrix using the record of the numerous solar storms recorded by COSTEP from 1996 to 2002. To test this matrix, Posner tested it on COSTEP data from 2003; it successfully predicted all of the solar storms that took place in 2003, with it providing advanced warnings from anywhere between 7 and 74 minutes. However, the method is not yet perfect, providing false alarms for weak storms or no storms at all. Posner is perfecting this method with the massive amounts of data available from COSTEP, which was launched in 1995.

This method is under consideration by Johnson Space Center for future lunar missions. It will help protect astronauts from these dangerous storms, helping mankind reach further into space.

For more information, visit:

• Space.com (Story, SOHO)
  
• Wikipedia(Solar and Heliospheric Observatory)