ESO Top 10 Astronomical Discoveries


ESOcast 75: ESO’s Top 10 Discoveries. Download and more info


Observations with ESO telescopes have led to many breakthroughs in astronomy, and, over the years, have been responsible for some truly remarkable findings. Here is our list of ESO´s Top 10 astronomical discoveries so far.

  1. Stars orbiting the Milky Way black hole

    Several of ESO's flagship telescopes were used in a 16-year long study to obtain the most detailed view ever of the surroundings of the monster lurking at the heart of our galaxy — a supermassive black hole.
    Science papers:
    Schödel et al. 2003 (Telbib),
    Gillessen et al. 2009 (Telbib)
    Read more in the ESO Press Release eso0226eso0846eso1151eso1332 and eso1512. The Crafoord Prize in Astronomy 2012 was awarded for this result.

  2. Accelerating Universe

    Two independent research teams, based on observations of exploding stars, including those from ESO's telescopes at La Silla and Paranal, have shown that the expansion of the Universe is accelerating. The 2011 Nobel Prize in Physics was awarded for this result.
    Science papers:
    Perlmutter et al., 1999ApJ...517..565P (Telbib),
    Riess,A. et.al., 1998, AJ116 1009 (Telbib),
    Schmidt, B. et.al., 1998, ApJ 507 46 (Telbib),
    Perlmutter, S. et al, 1998, Nature, vol. 391, 51 (Telbib),
    Tonry, J.L. et al, 2003, ApJ (Telbib),
    Knop, R.A. et al, 2003, ApJ (Telbib),
    Riess, A. et al, 2004, ApJ (Telbib),
    Astier, P. et al, 2006, A&A (Telbib)
    Read more in the ESO Press Release eso9861

  3. Revolutionary ALMA image reveals planetary genesis

    In 2014, ALMA, the Atacama Large Millimeter/submillimeter Array, revealed remarkable details of a solar system that is forming. The images of HL Tauri were the sharpest ever made at submillimetre wavelengths. They show how forming planets are vacuuming up dust and gas in a protoplanetary disc.
    Read more in the ESO press release eso1436

  4. First image of an exoplanet

    The VLT has obtained the first-ever image of a planet outside our Solar System. The 5-Jupiter-mass planet orbits a failed star — a brown dwarf — at a distance of 55 times the mean Earth-Sun distance.
    Science paper:
    Chauvin et al. 2004 (Telbib)
    Read more in the ESO Press Release eso0428

  5. Oldest star known in the Milky Way

    Using ESO's VLT, astronomers have measured the age of the oldest star known in our galaxy, the Milky Way. At 13.2 billion years old, the star was born in the earliest era of star formation in the Universe. Uranium has also been detected in a Milky Way star and used as an independent estimate of the age of the galaxy.
    Science paper:
    Pasquini et al. 2004 (Telbib)
    Cayrel, R et al, 2001, Nature
    Read more in the ESO Press Release eso0425 and in the ESO Press Release eso0106

  6. Direct measurements of the spectra of exoplanets and their atmospheres

    The atmosphere around a super-Earth exoplanet has been analysed for the first time using the VLT. The planet, which is known as GJ 1214b, was studied as it passed in front of its parent star and some of the starlight passed through the planet’s atmosphere. The atmosphere is either mostly water in the form of steam or is dominated by thick clouds or hazes. This follows from the earlier first direct spectrum of an exoplanet.
    Science papers:
    Bean, J. et al, 2010, Nature
    Janson, M. et al, 2010, ApJ

    Read more in the ESO Press Release eso1047 and in the ESO Press Release eso1002

  7. Cosmic temperature independently measured

    The VLT has detected carbon monoxide molecules in a galaxy located almost 11 billion light-years away for the first time, a feat that had remained elusive for 25 years. This has allowed astronomers to obtain the most precise measurement of the cosmic temperature at such a remote epoch.
    Science paper:
    Srianand, R. et al, 2008, A&A (Telbib)
    Noterdaeme et al., A&A (Telbib)
    Read more in the ESO Press Release eso0813

  8. Richest planetary system

    Astronomers using ESO’s HARPS have discovered a planetary system containing at least five planets, orbiting the Sun-like star HD 10180. Also evidence that two other planets may be present, one of which would have the lowest mass ever found. Furthermore, the team also found evidence that the distances of the planets from their star follow a regular pattern, as also seen in our Solar System.
    Science paper:
    Lovis, C. et al, 2010, A&A
    Read more in the ESO Press Release eso1035

  9. Gamma-ray bursts –  the connections with supernovae and merging neutron stars

    ESO telescopes have provided definitive proof that long gamma-ray bursts are linked with the ultimate explosion of massive stars, solving a long-time puzzle. In addition a telescope at La Silla was able for the first time to observe the visible light from a short gamma-ray burst, showing that this family of objects most likely originate from the violent collision of two merging neutron stars.
    Science papers:
    Galama T.J., et al., 1998, Nature
    Hjort et al., 2003 (Telbib)
    Hjorth, J., et al., 2005, Nature
    Pian, E., et al., 2006, Nature
    Read more in the ESO Press Release eso0318 and in the ESO Press Release eso0533

  10. Best observational evidence of first generation stars in the Universe

    Astronomers using ESO’s Very Large Telescope have discovered by far the brightest galaxy yet found in the early Universe and found strong evidence that examples of the first generation of stars lurk within it — stars that were previously only theoretical. These massive, brilliant objects were the creators of the first heavy elements in history — elements that are necessary to forge the stars we see around us today, the planets that orbit them, and life as we know it.
    Science paper:
    Sobral, D., et al., 2015, Nature
    Read more in the ESO press release eso1524