A collection of small, clear quartz crystals unearthed in South Africa has given researchers from the University of Rochester a new clue about when our planet’s magnetic field formed. In the northern Limpopo province of South Africa, an arid, rocky terrain called Barberton Mountain Land has some of Earth’s oldest exposed stone—some more than three billion years old. By studying magnetized metal particles within ancient quartz found there, researchers discovered that the crystals formed in the presence of Earth’s magnetic field. The field that enveloped the planet at that time was only about half as strong as it is today, the scientists say. This discovery implies that our planet generated a weak magnetic field as far back as 3.4 billion years ago, well before the atmosphere became rich with oxygen (about 2.3 billion years ago).

This force field protected our young planet from high-energy charged particles in the solar wind and high-energy radiation emanating from the Sun. Now, billions of years later, this magnetic field sustains our current atmosphere. Without the protective shielding, charged particles streaming from the Sun would rip apart the water and oxygen in our atmosphere. Researchers think that the presence of our planet’s magnetic field was important for the development and survival of life on Earth as we currently know it.

Check out the Science Bulletins website to discover more new astronomy research.

The VISTA telescope at Chile’s Paranal Observatory, which has been up and running since December 2009, has captured stunning new images of the Orion Nebula. By measuring infrared radiation emanating from the famous nebula, the telescope has finally seen into the heart of the vast stellar nursery.

This nebula, which is located below the “belt” of the constellation of Orion, can typically be seen from Earth with the naked eye. Large clouds of dust, however, have blocked optical wavelengths of light from reaching telescopes, preventing a clear view of the nebula’s center. By detecting the infrared radiation that penetrates dust clouds, astronomers are finally getting a look at the young stars shining in this previously hidden portion of the nebula.

These images are some of the first to be released from the new VISTA telescope; already they hint at the valuable new perspective astronomers are gaining by looking at the sky in near-infrared wavelengths of light.

To learn about other recent advances in astronomy, check out the Science Bulletins website.

NASA has recently released images from the Hubble Space Telescope that catch Pluto changing with the seasons. The images, which were taken of the distant dwarf planet in 2002 and 2003, show dramatic changes in the appearance of Pluto’s polar surfaces. Compared to images taken in 1994, Pluto’s north pole is getting brighter, and its south pole is getting darker. Astronomers believe that its icy northern surface is melting, while the southern hemisphere’s pole is freezing. This is evidence that summertime is approaching for Pluto’s northern hemisphere.

See Pluto go from spring to summer in this week’s Astro Bulletin:

Earth’s seasons result from our planet’s tilt: its rotational axis is angled about 23 degrees off its orbital axis. When this tilt orients one hemisphere toward the Sun, summer occurs in that half of the Earth. The solar radiation hits that hemisphere more directly and for a longer period of time each day. At the same time, the opposite hemisphere experiences a winter season, because it receives solar rays that are less direct.

Pluto experiences seasons largely for the same reason, but its cycles are more complicated than Earth's. The dwarf planet’s rotational axis is tilted a whopping 120 degrees, so its seasonal effects are more extreme. Unlike Earth, whose orbit follows nearly a perfect circle around the Sun over 365 days, Pluto has a slightly elliptical (oval-shaped) orbit that takes 248 years. This results in complex patterns of radiation over time, making Pluto a challenging world to understand. Continued observations from Hubble as well as the New Horizons spacecraft now traveling toward Pluto will help scientists test and refine their theories about Pluto’s seasonal surface changes.

Check out the Science Bulletins website to learn more recent findings in astronomy.