(CNN) -- More than two weeks after the disappearance of Malaysia Airlines Flight 370, finding it remains a global search-and-rescue effort. The bulk of the attention is on the southern Indian Ocean, where satellites have photographed objects that authorities say could be related to the search.
Authorities have called the images the best lead yet on where the missing plane might be, and have been searching an area more than 1,500 miles (2,400 kilometers) southwest of Australia. So far, they have turned up nothing.
What's the very latest?
French authorities passed on a new set of images showing "potential objects in the vicinity of the southern corridor" of the search area for the plane, Malaysia's acting transportation minister said Sunday. Satellite images issued by Australian and Chinese authorities have previously pointed to possible large floating objects.
On Sunday, eight airplanes flew over the southern Indian Ocean searching for the missing plane, said Australian Maritime Safety Authority spokeswoman Andrea Hayward-Maher.
That's two planes more than Saturday, and the most aircraft involved in the search led by Australia so far, she said.
Sunday's search was a visual search, AMSA rescue spokesman Mike Barton told reporters. Eyes took precedence over radar.
The planes planned to base their movements on Chinese satellite images of debris and drift modeling, the AMSA said.
On Saturday, searchers found a wooden pallet as well as strapping belts, AMSA's John Young said. The use of wooden pallets is common in the airline industry.
"It's a possible lead ... but pallets are used in the shipping industry as well." he said Sunday. Authorities have said random debris is often found in the ocean.
What about the lithium-ion batteries?
Malaysia Airlines CEO Ahmad Jauhari Yahya previously confirmed that the plane was carrying lithium-ion batteries.
Lithium-ion batteries are the type commonly used in laptops and cell phones, and they have been known to explode, although it is a rare occurrence.
A fire blamed on lithium-ion batteries caused the fatal 2010 crash of a UPS cargo plane in Dubai. Lithium-ion batteries used to power components in Boeing 787 aircraft were also implicated in a series of fires affecting that plane.
So, in theory, a cargo of the batteries could have caused a fire that led Flight 370 to crash.
But Yahya told reporters the batteries were routine cargo.
"They are not declared dangerous goods," he said, adding that they were "some small batteries, not big batteries."
We saw the first satellite photos of objects on Thursday. Why haven't searchers found anything?
The area being searched is enormous and remote. Military surveillance aircraft can stay over the scene just two hours before having to return to base, although the long-range corporate jets can manage as long as five hours above the target area. And given that the objects spotted on satellite could have drifted hundreds of miles since they were photographed, or maybe have even sunk by now, finding them isn't a simple proposition.
Japan is sending surveillance planes, more merchant ships are on the way, and Australia, Britain, China and Malaysia are all sending ships to the search area -- a remote region far from commercial shipping and air lanes.
Is it possible that the plane could have gone that far?
Investigators think so. They concluded the plane flew for hours after disappearing from radar, and calculated a pair of arcs running north and south from the Malay Peninsula for likely locations. Based on those trajectories, the amount of fuel on board and other factors, experts believe the plane could have made it to the southern Indian Ocean.
What do the first satellite images show?
The commercial images released Thursday show two indistinct objects, one about 88 feet (27 meters) in length and the other about 16 feet (5 meters) long. Though the pictures don't look like much to the untrained observer, Australian intelligence imagery experts who looked at them saw enough to pass them along to AMSA, said Young.
"Those who are expert indicate they are credible sightings. And the indication to me is of objects that are reasonable size and are probably awash with water, bobbing up and down out of the surface," he said.
They were taken by commercial satellite imaging company DigitalGlobe on March 16.
Then why did we only hear about them on Thursday?
Basically, the Australians say, it's because the Indian Ocean is a very big place. The maritime safety authority said it took four days for the images to reach it "due to the volume of imagery being searched and the detailed process of analysis that followed."
And what about the Chinese satellite image?
It was taken two days later, on March 18. A photograph posted on the official website of the State Administration of Science, Technology and Industry for National Defense shows the "suspected floating object" in waters about 75 miles southwest of the unidentified objects spotted by Australia, Chinese authorities said.
China will be sending ships to verify the possible find, the Malaysian acting transport minister said.
Australian authorities said China had shared the image Saturday evening and that the possible object's location falls within the 36,000-square kilometer area searched Saturday. The information will be factored into Sunday's search, they said. Two merchant navy ships and an Australian naval vessel are now in the area.
Who is running the search?
The Australians are in charge of the search in their area of responsibility in a large area of the southern Indian Ocean off Australia's west coast. Malaysia remains in overall control of the search.
How did they know to look in this area?
Investigators analyzing satellite pings sent by the plane concluded it was traveling along one of two arcs away from the Malay Peninsula. U.S. officials have said they believe the plane most likely traveled south and crashed into the Indian Ocean.
Searchers narrowed the area of interest by calculating the most likely locations based on time in the air, fuel usage and other factors.
When will we know whether the objects are from the missing flight?
Maybe never. Searchers might miss them, or they might have sunk by now.
But even if they do find one of the objects, the process of determining whether it's from the missing flight could still be lengthy.
"We have to locate it, confirm that it belongs to the aircraft, recover it and then bring it a long way back to Australia, so that could take some time," Young said.
Could pieces of the plane still be floating?
Probably not any big pieces, according to Steve Wallace, the U.S. Federal Aviation Administration's former director of accident investigation. But pieces of lightweight debris, such as life jackets and seat cushions, can float for days after an aircraft strikes the water, he said.
If it's not the plane, what else could it be?
Almost anything big and buoyant. The objects were spotted in a part of the Indian Ocean known for swirling currents called gyres that can trap all sorts of floating debris. Among the leading contenders for what the objects might be, assuming they're not part of Flight 370: shipping containers that fell off a passing cargo vessel. There are reasons to doubt that theory, however. The area isn't near commercial shipping lanes, and the larger object photographed by commercial satellite seems to be nearly twice as long as a standard shipping container.
If it is the plane, would its location tell us anything about what happened on that flight?
If it really is the wreckage of the Boeing 777-200, its far southern location would provide investigators with precious clues into what terrible events unfolded to result in the disappearance and loss of the airliner, according to Robert Goyer, editor-in-chief of Flying magazine and a commercial jet-rated pilot. "The location would suggest a few very important parameters. The spot where searchers have found hoped-for clues is, based on the location information provided by the Australian government, nearly 4,000 miles from where the airliner made its unexpected and as yet unexplained turn to the west," Goyer wrote in a column for CNN.com. The first obvious clue is that the airplane flew for many hours.
It's already been nearly 16 days. Are we running out of time to find this plane?
The locator beacons attached to flight data recorders are designed to ping for at least 30 days, but will probably keep going at full strength up to five days longer, said Anish Patel, president of Dukane Seacom, the Florida company that believes it made Flight 370's beacons.
"Our predictive models and lab tests show 33 to 35 days of output before we drop below the minimal values," Patel told CNN. "Depending on the age of the battery, it could continue pinging for a few days longer."
Pinging is one thing. Finding the pings is another.
Not only is the search area vast, it is deep -- up to 13,000 feet in many places. Given that the pingers can be detected from no more than about 2 miles away, they could be hard to hear if they're on the bottom of the deepest part of the ocean.
Layers of different water temperatures could also make it tough to pick up the sound of the beacons, experts say.
CNN's Steven Jiang, Andrew Stevens and Mike M. Ahlers contributed to this report.