This site may earn affiliate commissions from the links on this page. Terms of utilize.

iris nebula

NASA has announced new information from the Iris Nebula they think could shed lite on the origin of life. Its findings help strengthen the idea that life on World could have been kickstarted past the arrival of material from space, and could help scientists understand how the first units of life got their start.

For me, the image of life's origin on Earth has always been pretty set up past a scene from Star Trek: The Adjacent Generation. In that prove, the all-powerful character of Q transports Picard back to primordial Earth to testify him the instant of human creation — an unheralded moment in which one chemical molecule unthinkingly interacts with another to create the crucial complex molecule that volition lead to the start living Earthling, and it all takes place in, as Q says, a "little pond of goo." But that episode (the serial finale) is more than 22 twelvemonth former, and these days there'due south at least as much real scientific support for a much more spectacular theory of life'due south kickoff on Earth: Maybe instead of a silent pond of goo, life on Earth got started in a great big bear on from space.

origin of life 3

Combination of three colour images of the Iris Nebula from SOFIA (reddish & light-green) and Spitzer (bluish) evidence dissimilar populations of PAH molecules.
Credits: NASA/DLR/SOFIA/B. Croiset, Leiden Observatory

The idea is that the Earth was seeded either with life (a theory called panspermia) or, far more likely, with the building blocks for life. It's non a new theory. Merely models for just how this seeding might have taken place, from which other parts of the universe, and with what types of molecules, take been very tentative. Astronomy has given theoreticians a better and better understanding of what raw materials might exist abundant in space, and might thus exist available to get in at Earth via an asteroid or comet. With new astronomical techniques, even so, it's becoming e'er more possible for scientists to practise it the other way around — to come up with candidate molecules and then have astronomers get out and look for them them.

I such possible type of life-giving molecule is the polycyclic aromatic hydrocarbon (PAH) — you tin can basically read this every bit "multi-ringed, stable molecule made of only carbon and hydrogen." Why are PAHs of import to life? Because it's thought that they could be modified through plausible chemical and electromagnetic interactions to create a whole slew of circuitous molecules that might take been necessary for Earth'due south first spark of life. Chief amidst these are amino acids — take sure PAHs and bailiwick them to merely the right sequence of natural rut, radiations, and chemical pressures, and you might only end upwards with something rather like a small-scale, simple protein edifice block. Note that one of these "pressures" can be the heat of the bear on between the comet conveying the PAHs, and the surface of the Earth.

pah life origin 2The readings come from SOFIA (stratospheric observatory for infrared astronomy), which looked at the Iris Nebula with its FLITECAM near-infrared camera and the FORCAST mid-infrared camera. Emissions at ii particular wavelengths tin can be interpreted to guess the molecules' size, and what they found was a reliable distribution of PAHs past size. Close in to the star, the average PAH molecule is much larger than in the cloud farther away.

Their explanation for this is that the harsh radiation of the star both destroys smaller molecules close in, and hits medium-sized molecules with enough energy to combine them into larger ones. This is at odds with the expectation, that the radiation from a nearby star would destroy such molecules entirely. Just the novel source of large aromatic hydrocarbons could strengthen the idea that circuitous molecules came to Earth from space.

The nearly common argument against the seeded-from-infinite hypothesis is that it requires the input of molecules that many believe would non realistically exist available in large quantities — that is, without life already in beingness to create it. But information technology'southward becoming increasingly articulate that the sheer variety of environments in the universe can forge all kinds of seemingly improbable things. Astronomers are slowly compiling a list of natural molecular factories scattered around the universe — maybe life simply requires a habitable planet that's lucky enough to receive a shipment from the perfect combination of factories. Or, more than provocatively, a perfect combination, merely one of a multitude of starting points that could requite ascent to sustainable life throughout the universe.

Header image courtesy of NASA.