Einstein revisited

A century ago, Albert Einstein published his famous theory of relativity. He proposed that all objects physically warp the fabric of space, with larger masses producing a more pronounced effect, and very massive objects (such as the Sun) causing light to travel along curved paths through space. Such an effect was first observed during the 1919 solar eclipse by English astronomer Arthur Eddington.

Researchers had to wait a century, however, to get a telescope powerful enough to detect this gravitational microlensing caused by a star outside the Solar System. Even around objects with very large masses, such as stars, this effect is very slight, making such detections extremely challenging for ground-based telescopes. It is, however, within the capabilities of the NASA/ESA Hubble Space Telescope, which gathered the data comprising this Picture of the Week.

The bright star in the centre of the image is the nearby white dwarf Stein 2051B, only 17 light-years from Earth. The smaller star below is about 5000 light-years away. Astronomers observed Stein 2051B eight times within two years while the white dwarf travelled in front of of the distant background star. During the close alignment, the white dwarf’s gravity bent the light from the distant star, making it appear offset by about 2 milliarcseconds from its actual position. This deviation is so small that it is equivalent to observing an ant crawl across the surface of a 1€ coin from 2300 kilometres away.

 

Links:

Credit:

NASA, ESA, and K. Sahu (STScI)

About the Image

NASA press release
NASA caption
Id:potw1724a
Type:Observation
Release date:12 June 2017, 06:00
Size:1200 x 900 px

About the Object

Name:Stein 2051
Type:Milky Way : Star : Evolutionary Stage : White Dwarf
Distance:18 light years
Constellation:Camelopardalis
Category:Stars

Image Formats

Large JPEG
157.1 KB
Screensize JPEG
106.0 KB

Zoomable


Wallpapers

1024x768
135.2 KB
1280x1024
170.8 KB
1600x1200
208.7 KB
1920x1200
229.6 KB
2048x1536
278.3 KB

Coordinates

Position (RA):4 31 14.96
Position (Dec):58° 58' 13.75"
Field of view:0.16 x 0.12 arcminutes
Orientation:North is -0.0° left of vertical

Colours & filters

BandWavelengthTelescope
Optical
V
606 nm Hubble Space Telescope
WFC3
Optical
I
814 nm Hubble Space Telescope
WFC3

Also see our


Accelerated by CDN77