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.

NASA’S Hubble Space Telescope has looked into deeper into the universe—and further back in time—than ever before. And it’s turned up a suite of galaxies that are new to astronomers. As announced by NASA on January 5, 2010, images of these distant galaxies are giving astronomers a rare peek at how the universe looked not long after the Big Bang.

These new galaxies were discovered in the most recent images of a long-term Hubble survey called the Ultra Deep Field. Last summer, the telescope reexamined the patch of the sky it had last glimpsed back in 2004. This time, however, a different set of galaxies was detected with the telescope’s new infrared camera. The camera captures incoming light in infrared wavelengths, which are longer than what our eye and typical camera lenses can see.

Because our Universe is expanding, these distant galaxies appear to be moving away from Earth. The farther away an astronomical object is, the faster that apparent motion occurs. The motion alters the appearance of the visible light emitted by the galaxies, which is why they have eluded astronomers for so long. The apparent motion elongates the wavelengths of light—called “redshifting”—making the visible light reach Hubble’s new camera as infrared light. (The process is identical to the Doppler effect, which causes the sound a motorcycle makes to deepen as it speeds away from us.) The amount of redshift astronomers observe tells them just how far away the object is. For more on measuring distances with redshift, check out this interactive feature from Science Bulletins.

The new Hubble images indicate that the galaxies are 13 billion light-years away. The light has taken 13 billion years to reach Hubble’s camera, which means we see the galaxies as they were 13 billion years ago—just 600 to 800 million years after the Big Bang. This time stamp will help astronomers study the evolution of the early Universe, including how the first stars formed and how galaxies grew from clusters of early stars. To see the most recent Ultra Deep Field image from Hubble, have a look at this week’s Astro Bulletin.

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