MessageToEagle.com - Abell 68, pictured here in infrared light, is one of these galaxy clusters, and it greatly boosts the power of
Hubble, extending the The NASA/ESA Hubble Space Telescope’s ability to observe distant and faint objects.
This comes in the form of Einstein’s general theory of relativity, which makes galaxy clusters act as natural lenses,
amplifying the light coming from very distant galaxies.
The fuzzy collection of blobs in the middle and upper left of the image is a swarm of galaxies, each with hundreds of
billions of stars and vast amounts of dark matter.
Click on image to enlarge
Hubble image of Abell 68. Image credit: NASA & ESA. Acknowledgement: N. Rose
The effect of this huge concentration of matter is to deform the fabric of spacetime, which in turn distorts the
path that light takes when it travels through the cluster.
For galaxies that are even further away than the cluster —
which is already at the impressive distance of two billion light-years — and which are aligned just right, the effect
is to turn galaxies that might otherwise be invisible into ones that can be observed with relative ease.
Although the resulting images projected to us of these distant galaxies are typically heavily deformed, this process,
called gravitational lensing, is a hugely valuable tool in cosmology, the branch of astronomy which deals with the
origins and evolution of the Universe.
These distorted images of distant galaxies are a particularly fine example of this phenomenon.
In the middle of the image are a large number of galaxies stretched out into almost straight streaks of light that
look like shooting stars.
Meanwhile, just above and to the right of the large, bright elliptical galaxy in the upper left of the image is a
spiral galaxy whose apparent shape has been stretched and mirror-morphed into the shape of an alien from the classic
1970s computer game Space Invaders!
A second, less distorted image of the same galaxy appears to the left of the
Another striking feature of the image, albeit one unrelated to gravitational lensing, is the galaxy in the top right corner
of the image. What appears to be purple liquid dripping from the galaxy is a phenomenon called ram pressure stripping.
Click on image to enlarge
Annotated Hubble image of Abell 68. Image credit: NASA & ESA. Acknowledgement: N. Rose
The gas clouds within the galaxy are being stripped out and heated up as the galaxy passes through a region of denser
This image comes from the infrared channel of Hubble’s Wide Field Camera 3, combined with near-infrared observations
from the Advanced Camera for Surveys. This offers a modest taster of the kind of images that will come from the forthcoming
NASA/ESA/CSA James Webb Space Telescope, which is scheduled for launch in 2018.
Infrared images are particularly useful for studying very distant objects whose light is redshifted into the infrared by
the expansion of the Universe, as well as for peering through dust clouds which are opaque to visible light.
The Webb telescope will produce images which are sharper than Hubble’s infrared images, but more importantly,
it will be much more sensitive, thanks to its advanced sensors and larger primary mirror.
Beautiful Night Sky Timelapse
Takes You On A Journey To Astronomer's Paradise
There are not many locations left on this planet where you can still experience a dark sky like this.
Walking on the desert near Paranal between the scattered stones and boulders on the pale red dust feels like being on Mars but under the Earth sky.
It is an amazing experience to be under an ideal night sky, a pure natural beauty unspoiled by urban lights.