Planes searching for the Malaysia Airlines Flight 370 which disappeared six days ago with all 239 people on board have started heading towards the area where it is believed to have crashed. This follows the release by Chinese satellite probing the mysterious disappearance of “observed a suspected crash area at sea.”

China’s State Administration for Science, Technology and Industry for National Defense announced the discovery, including images of what it said were “three suspected floating objects.”

The objects aren’t small: 13 by 18 meters (43 by 59 feet), 14 by 19 meters (46 by 62 feet) and 24 by 22 meters (79 feet by 72 feet). For reference, the wingspan of an intact Boeing 777-200ER like the one that disappeared is about 61 meters (200 feet), and the plane’s overall length is about 64 meters (210 feet).

The images were captured around 11 a.m. on March 9, the day after the plane went missing, but weren’t released until Wednesday.

The Chinese agency gave coordinates of 105.63 east longitude, 6.7 north latitude, which would put it in waters northeast of where it took off in Kuala Lumpur, Malaysia, and south of Vietnam, near where the South China Sea meets the Gulf of Thailand.

“It’s where it’s supposed to be,” Peter Goelz, a former National Transportation Safety Board managing director, told CNN’s Jake Tapper, noting the “great skepticism” about reports the plane had turned around to go back over Malaysia. “I think they’ve got to get vessels and aircraft there as quickly as humanly possible.”

This isn’t the first time authorities have announced the discovery of objects or oil slicks that might be tied to aircraft. Still, it is the latest and comes on the same day that officials, rather than narrowing the search area, more than doubled it from the day earlier to nearly 27,000 square nautical miles (35,000 square miles).

The vastness of the area and the limited details that authorities have given makes it hard to tell whether the spot that the satellite imagery captured has been searched. A Malaysian air force official, who is not authorized to speak to the media, did say Thursday morning that its aircraft were heading to that area.

Bill Palmer – author of a book on Air France’s Flight 447, which also mysteriously went missing before its remnants were found – said having a search area of that size is immensely challenging. He compared it to trying to find something the size of a car or truck in Pennsylvania, then widening it to look for the same thing in all of North America.

“It’s a very, very difficult situation to try to find anything,” Palmer told CNN’s Brooke Baldwin. “Looking for pieces on the shimmering water doesn't make it any easier.”

The Chinese satellite find could help, significantly, in that regard.

“I think the size of the pieces ... everything we’ve heard... gives good cause to believe that we’ve now (refocused) the area,” former Federal Aviation Administration official Michael Goldfarb told CNN. “And that’s a huge relief to everybody ... I think it’s a high chance that they’re going to confirm that these (are) pieces of the wreckage.”

But not every expert was convinced this is it. Clive Irving, a senior editor with Conde Nast Traveler, said that the size of the pieces – since they are fairly square and large – “don’t conform to anything that's on the plane.”

Tom Haueter, a former NTSB aviation safety director, said he’d be “surprised” if the objects came from the plane, rationalizing that anything that big wouldn’t float.

Regardless, time is of the essence – both for investigators and the loved ones of the plane’s 239 passengers and crew, who have waited since Saturday for any breakthrough that would provide closure.

The flight data recorders should “ping,” or send out a signal pointing to its location, for about 30 days from the time the aircraft set off, noted Goldfarb. After that, Flight 370 could prove exponentially harder to find.

“It’s the only clue that we’ve had so far,” CNN aviation expert Richard Quest said of the satellite imagery clues. “If this doesn’t prove to be the wreckage of 370, then we’re back to square one.”

•Pieced together from reports by CNN and The Guardian of London. Photo shows site of a crashed plane.