Category: astrophysics

A new composite of the Crab Nebula with Chandr…

A new composite of the Crab Nebula with Chandra (blue and white), Hubble (purple), and Spitzer (pink) data has been released.

Credit: NASA

cosmic microwave background The cosmic micr…

cosmic microwave background

The cosmic microwave background (CMB) is electromagnetic radiation as a remnant from an early stage of the universe in Big Bang cosmology. In older literature, the CMB is also variously known as cosmic microwave background radiation (CMBR) or “relic radiation”. The CMB is a faint cosmic background radiation filling all space that is an important source of data on the early universe because it is the oldest electromagnetic radiation in the universe, dating to the epoch of recombination.

With a traditional optical telescope, the space between stars and galaxies (the background) is completely dark. However, a sufficiently sensitive radio telescope shows a faint background noise, or glow, almost isotropic, that is not associated with any star, galaxy, or other object. This glow is strongest in the microwave region of the radio spectrum. The accidental discovery of the CMB in 1964 by American radio astronomers Arno Penzias and Robert Wilson was the culmination of work initiated in the 1940s, and earned the discoverers the 1978 Nobel Prize in Physics.


The discovery of CMB is landmark evidence of the Big Bang origin of the universe. When the universe was young, before the formation of stars and planets, it was denser, much hotter, and filled with a uniform glow from a white-hot fog of hydrogen plasma. As the universe expanded, both the plasma and the radiation filling it grew cooler. When the universe cooled enough, protons and electrons combined to form neutral hydrogen atoms. Unlike the uncombined protons and electrons, these newly conceived atoms could not absorb the thermal radiation, and so the universe became transparent instead of being an opaque fog. Cosmologists refer to the time period when neutral atoms first formed as the recombination epoch, and the event shortly afterwards when photons started to travel freely through space rather than constantly being scattered by electrons and protons in plasma is referred to as photon decoupling.


Basically, cosmic microwave background radiation is the fossil of light, resulting from a time when the Universe was hot and dense, only 380,000 years after the Big Bang.

Cosmic microwave background radiation is an electromagnetic radiation that fills the entire universe, whose spectrum is that of a blackbody at a temperature of 2.725 kelvin.


Cosmic microwave background radiation, along with the spacing from galaxies and the abundance of light elements, is one of the strongest observational evidences of the Big Bang model, which describes the evolution of the universe. Penzias and Wilson received the Nobel Prize in Physics in 1978 for this discovery

source, source in portuguese

images credit: 

Image credit: Institute of Astronomy / National Tsing Hua University/ NASA/ESA Hubble, wikipedia

This stunning multi-mission picture shows off …

This stunning multi-mission picture shows off the many sides of the supernova remnant Cassiopeia A. It is made up of images taken by three of NASA’s Great Observatories, using three different wavebands of light. Infrared data from the Spitzer Space Telescope are colored red; visible data from the Hubble Space Telescope are yellow; and X-ray data from the Chandra X-ray Observatory are green and blue.

Image credit: NSA/JPL

Supernova in the Galaxy M51 discovered on June…

Supernova in the Galaxy M51 discovered on June 2, 2011


The Sudbury Neutrino Observatory (SNO) Lo…

The Sudbury Neutrino Observatory (SNO)

Located in a cave more than a mile underground in Canada, SNO can be thought of as a type of telescope, though it bears little resemblance to the image most people associate with that word. It consists of an 18-meters-in-diameter stainless steel geodesic sphere inside of which is an acrylic vessel filled with 1000 tons of heavy water (deuterium oxide or D2O). Attached to the sphere are 9,522 ultra-sensitive light-sensors called photomultiplier tubes. When neutrinos passing through the heavy water interact with deuterium nuclei, flashes of light, called Cerenkov radiation, are emitted. The photomultiplier tubes detect these light flashes and convert them into electronic signals that scientists can analyze for the presence of all three types of neutrinos. 

Berkeley Lab

Mapping a Merger

Mapping a Merger

Standout stars

Standout stars

Twins with differences

Twins with differences

The loneliest firework display

The loneliest firework display

Herbig–Haro (HH) objects are small patches of …

Herbig–Haro (HH) objects are small patches of nebulosity associated with newly born stars, and are formed when narrow jets of partially ionized gas ejected by those stars collide with nearby clouds of gas and dust at speeds of several hundred kilometres per second. Herbig–Haro objects are ubiquitous in star-forming regions, and several are often seen around a single star, aligned with its rotational axis.

HH objects are transient phenomena that last less than a few thousand years. They can evolve visibly over quite short astronomical timescales as they move rapidly away from their parent star into the gas clouds of interstellar space (the interstellar medium or ISM). Hubble Space Telescope observations have revealed the complex evolution of HH objects over the period of a few years, as parts of the nebula fade while others brighten as they collide with clumpy material of the interstellar medium.

  • source
  • images: NASA/JPL, ESA, Hubble, Judy Schmidt