It looks like a fireball has been travelling through the sky.

Not so: this is actually a cloud that was captured earlier this week by photographer and weather blogger Rogerio Pacheco on the Portuguese island of Madeira. He published it on his blog and described the cloud as "the hand of God".

We spoke to the BBC weather meteorologist Aisling Creevey to find out why such a spectacular "fireball" tore up the morning sky.

It might surprise you that clouds with this type of structure are quite common, she says, but we usually don’t have the luxury of seeing them in this way.

The reason the cloud appeared like this was because light from the sun caught onto a clump of cloud at a lower altitude just as it came into contact with cloud higher up.

There are three layers of clouds, she explains. And this fireball seems to be mixing some layers. The dark features for instance, appear to be clouds at a "middle” altitude - 2,400 - 6,100m - called altostratus clouds.

In fact, clouds like this might be above us all the time, but we usually cannot distinguish the differing shades of grey from each other very clearly. "This cloud is no more complex than normal but just happens to [have been photographed at] the exact moment that the light was caught," says Creevey.

Another meterologist, Emma Sharples from the UK's Met Office agrees. She says: "I think the presence of a rising sun has made [it] appear more striking than the clouds alone would appear. We think they are probably cumulus clouds [cauliflower-shaped and fluffy], so pretty common, but enhanced by the light conditions."

Pacheco was lucky to have captured these images, as the cloud would not have appeared like this for long, possibly only a couple of minutes, adds Creevey.

Melissa Hogenboom is BBC Earth's staff writer. She is @melissasuzanneh on Twitter.

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