Space Science Update: Clockwork Stars and the Age of the Universe

Hubble Pinpoints White Dwarfs in Globular Cluster

Peering deep inside a cluster of several hundred thousand stars, NASA's Hubble Space Telescope uncovered the oldest burned-out stars in our Milky Way Galaxy. Located in the globular cluster M4, these small, dying stars - called white dwarfs - are giving astronomers a fresh...

M4 Ground-Based (NOAO) Image

This picture was created from observations with the T2KA CCD camera at the Kitt Peak National Observatory's 0.9-meter telescope in March 1995.

Ancient, White Dwarf Stars in the Milky Way Galaxy

Close Up of Ancient, White Dwarf Stars in the Milky Way Galaxy

Globular Cluster M4's Location in Milky Way

This illustration shows the location of the globular cluster M4 in our Milky Way Galaxy, which is depicted "edge-on" or from the side. Globular clusters like M4 are the first pioneer settlers of the Milky Way. Many coalesced to build the hub of our galaxy and formed billions of...

White Dwarfs in Globular Cluster M4

This graph shows the relationship between the temperature and brightness of a sampling of stars in the globular cluster M4. The line of dots at upper right represents main-sequence stars, those whose cores are fusing hydrogen. Normal stars like our Sun fall in the middle of this...

Age-Dating the Universe

This illustration outlines the two techniques astronomers have used to determine the universe's age. In the "traditional method," astronomers used measurements of the universe's expansion rate to calculate the age of the cosmos. They determined the expansion rate by measuring...

Birth of Our Galaxy

This is an artist's concept of the early formative years of our Milky Way galaxy, circa 12.7 billion years ago. That long ago, the majestic spiral arms of our galaxy had not yet formed; the sky was a sea of globular star clusters. The bright blue star cluster at center left is...

Animation Zoom into M4 Globular Cluster

Sequence begins with a backyard view of the Scorpius region, then zooms to the Hubble Space Telescope's Wide Field Planetary Camera view of the M4 globular star cluster, located in the Milky Way Galaxy's stellar halo. Circles fade in, indicating the location of the cooling white...

Globular Cluster Age: White Dwarf Ages in M4

NASA's Hubble Space Telescope has found the oldest burned-out stars in our Milky Way Galaxy. These extremely dim and old "clockwork stars" provide a completely independent reading of the age of the universe. By measuring the temperature of white dwarf stars in a globular star...