It’s traditional for the team behind the Hubble Space Telescope to release a jaw-dropping picture to celebrate the anniversary of the observatory’s launch in April 1990, and this year’s image might well rate a double jaw drop.
The science team’s greeting card for Hubble’s 27th birthday features side-by-side views of two spiral galaxies much like our own Milky Way galaxy, seen from two angles.
The edge-on galaxy at left, NGC 4302, is about 60 percent of the Milky Way’s size and contains about 10 percent of our home galaxy’s mass, the Hubble team says in today’s image advisory.
The galaxy at right, NGC 4298, is tilted about 70 degrees as seen from Earth, and measures about a third as wide as the Milky Way. It weighs in at 17 billion solar masses, which is less than 2 percent of the Milky Way’s 1 trillion solar masses.
The two galaxies share more than their spiral shape. They’re both about 55 million light-years away, both part of the Virgo Cluster in the constellation Coma Berenices. At their closest points, the two galaxies are separated by a mere 7,000 light-years. (In comparison, the Milky Way’s nearest spiral neighbor, the Andromeda Galaxy, is 2.3 million light-years away.)
Both galaxies were discovered in 1784 by English astronomer William Herschel. Both have been the focus of photographs more numerous than the galaxies in the Virgo Cluster. Nevertheless, winning a spot on a Hubble birthday card puts NGC 4302 and NGC 4298 in a special spotlight.
This view was captured by Hubble’s Wide Field Camera 3 in three visible-light bands, during three weeks’ worth of picture-taking sessions in January.
Hubble was launched into orbit aboard the space shuttle Discovery on April 24, 1990, and has been through five astronaut servicing missions since then. Twenty-seven is a ripe old age for a space mission, but scientists are hoping that Hubble will still be kicking long after next year’s scheduled launch of the next-generation James Webb Space Telescope.