In celebration of the 27th anniversary of the launch of NASA’s Hubble Space Telescope on April 24, 1990, astronomers used the legendary telescope to take a portrait of a stunning pair of spiral galaxies. This starry pair offers a glimpse of what our Milky Way galaxy would look like to an outside observer.
The edge-on galaxy is called NGC 4302, and the tilted galaxy is NGC 4298. These galaxies look quite different because we see them angled at different positions on the sky. They are actually very similar in terms of their structure and contents.
From our view on Earth, researchers report an inclination of 90 degrees for NGC 4302, which is exactly edge on. NGC 4298 is tilted 70 degrees.
In NGC 4298, the telltale, pinwheel-like structure is visible, but it’s not as prominent as in some other spiral galaxies. In the edge-on NGC 4302, dust in the disk is silhouetted against rich lanes of stars. Absorption by dust makes the galaxy appear darker and redder than its companion. A large blue patch appears to be a giant region of recent star formation.
Both galaxies are approximately 55 million light-years away. They reside in the constellation Coma Berenices in the Virgo Cluster of nearly 2,000 galaxies. Both were discovered in 1784 by astronomer William Herschel. Such objects were first simply called “spiral nebulas,” because it wasn’t known how far away they were. In the early 20th century, Edwin Hubble discovered that galaxies are other island cities of stars far outside our Milky Way.
A typical spiral galaxy has arms of young stars that wind outward from its center. The bright arms are regions of intense star formation. Such galaxies have a central bulge and are surrounded by a faint halo of stars. Many spiral galaxies also have bars that extend from the central bulge to the arms.
The edge-on NGC 4302 is about 87,000 light-years in diameter, which is about 60 percent the size of the Milky Way. It is about 110 billion solar masses, approximately one-tenth of the Milky Way’s mass.
The tilted NGC 4298 is about 45,000 light-years in diameter, about one third the size of the Milky Way. At 17 billion solar masses, it is less than 2 percent of the Milky Way galaxy’s 1 trillion solar masses.
The Hubble observations were taken between January 2 and January 22, 2017 with the Wide Field Camera 3 (WFC3) instrument in three visible light bands.
The Hubble Space Telescope was launched aboard the Space Shuttle Discovery on April 24, 1990 and deployed into low-Earth orbit the next day. From its perch high above the distorting effects of Earth’s atmosphere, Hubble observes the universe i near-ultraviolet, visible, and near-infrared light. Over the past 27 years, the space telescope’s breakthrough discoveries have revolutionized the fields of astronomy and astrophysics.
Credits
NASA, ESA, and M. Mutchler (STScI)| About The Object | |
|---|---|
| Object Name | NGC 4298, NGC 4302 |
| Object Description | Interacting Galaxies, Spiral Galaxies |
| R.A. Position | 12h 21m 42.08s |
| Dec. Position | 14° 37' 13.16" |
| Constellation | Coma Berenices |
| Distance | 55 million light-years (17 megaparsecs) |
| About The Data | |
| Data Description | These datasets are from the HST proposal , M. Mutchler, J. Green, Z. Levay, D. Smith, and R. Villard (STScI), and image processing by J. DePasquale. |
| Instrument | HST>WFC3/UVIS |
| Exposure Dates | January 2017; Exposure time: 418 minutes. |
| Filters | F475W (B), F555W (V), and F625W (r) |
| About The Image | |
| Color Info | This image is a composite of separate exposures made by the WFC3 instrument on the Hubble Space Telescope using two different cameras and filters isolating the light of broad wavelength ranges. The color arises by assigning different hues (colors), to each monochromatic image. In this case, the colors are: Blue: F475W (B) Green: F555W (V) Red: F625W (r) |
| Compass Image |  |
| About The Object | |
|---|---|
| Object Name | A name or catalog number that astronomers use to identify an astronomical object. |
| Object Description | The type of astronomical object. |
| R.A. Position | Right ascension – analogous to longitude – is one component of an object's position. |
| Dec. Position | Declination – analogous to latitude – is one component of an object's position. |
| Constellation | One of 88 recognized regions of the celestial sphere in which the object appears. |
| Distance | The physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs. |
| Dimensions | The physical size of the object or the apparent angle it subtends on the sky. |
| About The Data | |
| Data Description |
|
| Instrument | The science instrument used to produce the data. |
| Exposure Dates | The date(s) that the telescope made its observations and the total exposure time. |
| Filters | The camera filters that were used in the science observations. |
| About The Image | |
| Image Credit | The primary individuals and institutions responsible for the content. |
| Publication Date | The date and time the release content became public. |
| Color Info | A brief description of the methods used to convert telescope data into the color image being presented. |
| Orientation | The rotation of the image on the sky with respect to the north pole of the celestial sphere. |
