Backgrounder: Astronomical breakthoughs in recent years

Human beings have never stopped their painstaking yet brave journey into the vast space, with much progress made in exploration of outer space over recent years as a result of rapid development of science and technologies.

The following are a few astronomical breakthroughs made in space exploration over the past few years.

-- On February 12, 2001, the Near Earth Asteroid Rendezvous -- Shoemaker (NEAR Shoemaker) -- successfully landed on the near-Earth asteroid Eros, becoming the first man-made device landing on an asteroid.

-- In October 2001, 2001 Mars Odyssey, a robotic spacecraft orbiting the planet Mars developed by NASA, found much evidence for water on Mars in the form of images. And with its spectrometer, it proved there was a large amount of ice under the surface of Mars.

-- In January 2010, the Mars Reconnaissance Orbiter found the Mars has had a rich history of water-related processes. A major discovery was finding evidence of ancient hot springs.

-- On August 6, 2012, Curiosity Mars Rover landed on Mars. Curiosity Rover is by far the most expensive Mars exploring device ever made and is powered by a radioisotope thermoelectric generator. It is still roaming on the surface of Mars up to the present.

-- In 2013, scientists confirmed that Voyager 1 had entered the interstellar medium around August 25, 2012, making it the first human-made object to leave the Solar System. Voyager 1 is a space probe launched by NASA in 1977, to study the outer Solar System.

-- In 2014, researchers found traces of dark matter -- an elusive matter which is thought to make up more than 80 percent of the matter in the universe -- using data from NASA's Fermi Gamma-ray Space Telescope.

-- In July 2015, New Horizons, an interplanetary probe launched by NASA in 2006, flew pass Pluto in high speed. The probe took many high-definition images of the dwarf planet for the first time in history. Endi