I am angered by debunkers who write articles like this article in LiveScience.com. I don't mind sceptics, someone who is open to whatever the data suggests but unwilling to believe it suggests something out of the ordinary without actually seeing the data. But debunkers, who dismiss the data outright without ever having seen it are another matter altogether.

"Without some independent confirmation or other evidence, it’s hard to know what the United Airlines employees might have seen. But is it more likely that they saw an "optical illusion", or that a large, unknown object hovered over one of the country’s busiest airports without being seen by anyone else or appearing on radar?"

There were many witnesses that saw this object and were quite clear about what they had seen, including that it had punched a hole through the clouds when it left. Optical illusions don't do that.

The lights over Arkansas and Arizona had something in common: they were both seen near military bases, at a time when Air Force pilots were dropping very bright flares from parachutes during training. The flares, producing in some cases nearly 2 million candlepower, would be visible for miles.

Never mind the fact that many people witnessed a structure, not merely lights, including the former Governor of Arizona and that some got it on video.

I got one comment on the photographs I took that "it's a plane", in spite of the fact that there are photographs with planes and the shape can be resolved down to the point where the fuselage is only one or two pixels thick, and that spherical objects (which clearly show spherical reflective patterns) are about sixteen pixels wide in one picture, six pixels wide in the other, and in that other photo there are other objects in the same photo that do resolve down to one or two pixels.

And then there is the person in Surrey that keeps photographing the same kind of spherical plane which can't be brought into focus even in an optical telescope, the "blur" to them is a property of the object. I can't totally rule out a plane but if it's a plane it's one with the ability to hover for long periods of time with a very stealthy system that almost renders it invisible optically (though it remains highly visible in the infrared).

I do know about a type of plane, one that uses I guess we could coin the term magnetoplasmadynamics, in as much as it uses a nuclear reactor to provide power, a plasma torch to ionize the air, and a system of superconductive magnets to move the air through ports and produce thrust.

I am aware that there have been some primitive attempts at optical cloaking involving meta-materials that move light around an object such that you can see what is behind it but that at present these materials only function at one particular wavelength. Now perhaps black budget projects have developed this capability more than we know and somehow applied it to these nuclear magnetoplasmadynamic planes.

These "planes" normally take the form of a black triangle with three lights (which are the ports where the plasma is pumped through) at each corner. I don't see how the they could apply meta-material cloaking to this technology however since it would have to cover the ports and by doing so render the craft inoperable.

I won't deny the LiveScience.com, LINK authors note that both of these sightings appeared near Air Force bases. I think it's worth noting that the whole UFO phenomena seemed to take off right after we exploded the first atomic bomb. I can't help but wonder if we weren't discovered as a result. What was the cause of that gamma ray burst?

I also wonder why the author considers the possibility of extraterrestrial craft unlikely. In the universe there is something on the order of 1026 stars, give or take a few. In this galaxy alone there is somewhere around 1012. Approximately half of the stars we have surveyed have planetary systems and that is with the limitation of only being able to detect Jupiter sized planets or large in near orbits, with the rare exception of catching a planetary transit event. In this solar system Earth is definitely capable of harbouring life. Mars most likely has bacteria and possibly lichens. Several moons of Jupiter and Saturn may have under ice oceans capable of harbouring life.

Anybody that follows physics and how rapidly that field has evolved over the last hundred years or so must understand that our understanding of physics is far from complete.

So exactly what is it that makes extraterrestrial craft unlikely? Space is large yes, but so are the possibilities of life within that space. We don't know physics well enough to know there isn't a way of getting here from another star system in a timely manner. So exactly what is it that makes it unlikely? The truth is absolutely nothing.

Responsible science, it seems to me, would hold off making assumptions when inadequate data exists and instead would seek to add to the existing knowledge base.