It’s time to start watching for Comet PANSTARRS, one of two comets to get excited about in 2013. Photo: This image provided by NASA shoaws the comet PANSTARRS as seen from Mount Dale, Western Australia on March 5, 2013. According to NASA on March 10, it will make its closest approach to the sun about 28 million miles (45 million kilometers) away. As it continues its nightly trek across the sky, the comet may get lost in the sun's glare but should return and be visible to the naked eye by March 12. (Photo by AP Photo/NASA)

Visitors look at tropical fish transported from Japan's southern island of Okinawa displayed in a giant 14-ton fish tank at the Sony Square event space in Tokyo on July 17, 2016. The 45-day-long summer exhibition will be held through August 28 to display sea creatures common to the waters around Okinawa. (Photo by Kazuhiro Nogi/AFP Photo)

Balinese men hold cock fighters during the Tabuh Rah ceremony at a Temple in Gianyar, Bali, Indonesia, 28 December 2014. Traditional cockfighting or locally named “Tajen”, was once performed as a sacred ritual in Bali but now has become a source of gambling for many local Balinese men. Cockfighting is staged during the anniversary of a temple. The rituals are mainly aimed at preventing the evil spirits from harming people. (Photo by Made Nagi/EPA)

In this February 28, 2015 photo, teammates struggle to lift a bull off the trapped leg of a charro, during the bull riding event at a charreada in Mexico City. National Charros Association President Manuel Basurto Rojas said: “We in charreria are taking things into our own hands. We have codes, we have rules, for how to treat the animals. On the other hand, there is a lot of danger involved for the men doing these tricks”. (Photo by Rebecca Blackwell/AP Photo)

Iraqis run for cover as they flee Mosul's Al-Tayaran neighbourhood on February 28, 2017, during an offensive by Iraqi forces to retake the area from Islamic State (IS) group fighters. Hundreds of civilians fled through the desert to escape fighting and privation in Mosul, joining thousands of others who left their homes as conditions worsen in the city's west. (Photo by Ahmad Al-Rubaye/AFP Photo)

Mohammad, a 13-year-old fighter from the “Free Syrian Army”, plays with a cat in Aleppo's Bustan al-Basha district, Syria October 28, 2013. Mohammad joined the Free Syrian Army after his father died during clashes with the Syrian regime. The gun he is using was his father's. (Photo by Molhem Barakat/Reuters)

A woman wearing a mask reacts at her garden which locates next to chimneys of coal-fired power plant in Shijiazhuang, Hebei province, China, January 28, 2015. Beijing introduced tougher regulations this year to combat pollution, keen to overhaul China's unwanted image of smog-choked cities, fouled waterways and heavy-metal tainted soil. (Photo by Kim Kyung-Hoon/Reuters)

Mikhail Vasilenko, a participant from the Siberian town of Nizhny Tagil, works on an ice sculpture called “The Predator”, on the last day of the annual international festival of snow and ice sculptures “The Magical Ice of Siberia”, with the air temperature at about minus 28 degrees Celsius (minus 18.4 degrees Fahrenheit), in Krasnoyarsk, Russia, January 17, 2016. (Photo by Ilya Naymushin/Reuters)