Exploring The Universe

Spiral Galaxy NGC 3628 Edge On - November 1st, 1996.

"This is what a spiral galaxy looks like sideways. This view of NGC 3628 resembles our own Milky Way galaxy, which is also known to be a spiral. The dark band across the center is absorbed starlight caused by the galaxy's interstellar dust. NGC 3628 is the faintest member of the Leo Triplet, a group of galaxies dominated by M65 and M66. The Leo Triplet lies about 35 million light years distant. The center of NGC 3628 emits variable X-ray radiation, perhaps indicating the presence of a massive black hole."

Leo Triplet Spiral Galaxy M65 - August 12th, 1996.

"Spiral galaxy M65 is a normal spiral galaxy not unlike our own Milky Way. In fact, M65 is a typical spiral galaxy of a type that could be found anywhere in the local Universe. Given a morphological type of "Sa," M65 shows tightly wrapped spiral arms and a large nuclear central bulge. The central bulge stars are older and redder than disk stars, which appear more blue. Stars in the bulge of the our own Milky Way galaxy are also typically older and redder than stars in the disk where our Sun resides. M65 is a member of the Leo Triplet of galaxies, along with its neighbors M66 and NGC 3628. Although it appears that M65's gravity has distorted M66's symmetry, M65's symmetry seems unaffected by M66. M65 is located roughly 35 million light years away, so that light recorded today left after the fall of the dinosaurs but when many land mammals were just evolving on Earth."

Unusual Spiral Galaxy M66 - August 10th, 1996.

"Spiral galaxy M66 is the largest galaxy in a group known as the Leo Triplet. M66 is somewhat peculiar because of its asymmetric spiral arms. Usually dense waves of gas, dust, and newly formed stars - called spiral density waves - circle a galactic center and create a symmetric galaxy. Gravity from nearby Leo Triplet neighbor M65, however, has probably distorted this galaxy. In M66, intricate long dust lanes are seen intertwined with the bright stars that light up the spiral arms. Research indicates that M66 is unusual in that older stars are thought to heat up the dust in the galaxy's central bulge - a job attributed to young and hot stars in many other galaxies. M66 is famous for a powerful "Type Ia" supernova that was observed in 1989. Stellar explosions like this are thought to be nearly identical and so by noting how bright they appear, astronomers can estimate their true distance - and therefore calibrate the scale of the Universe!"