A rotating white dwarf shows different compositions on its opposite faces.

White dwarfs, the extremely dense remnants left behind by most stars after their death, are characterized by a mass comparable to that of the Sun compressed into the size of an Earth-like planet. In the resulting strong gravity, heavy elements sink towards the centre and the upper layer of the atmosphere contains only the lightest element present, usually hydrogen or helium1,2. Several mechanisms compete with gravitational settling to change a white dwarf's surface composition as it cools3, and the fraction of white dwarfs with helium atmospheres is known to increase by a factor of about 2.5 below a temperature of about 30,000 kelvin4-8; therefore, some white dwarfs that appear to have hydrogen-dominated atmospheres above 30,000 kelvin are bound to transition to be helium-dominated as they cool below it. Here we report observations of ZTF J203349.8+322901.1, a transitioning white dwarf with two faces: one side of its atmosphere is dominated by hydrogen and the other one by helium. This peculiar nature is probably caused by the presence of a small magnetic field, which creates an inhomogeneity in temperature, pressure or mixing strength over the surface9-11. ZTF J203349.8+322901.1 might be the most extreme member of a class of magnetic, transitioning white dwarfs-together with GD 323 (ref. 12), a white dwarf that shows similar but much more subtle variations. This class of white dwarfs could help shed light on the physical mechanisms behind the spectral evolution of white dwarfs.

The efficient Lamarckian spread of life in the cosmos.

In this Chapter we discuss the various mechanisms that are available for the possible transfer of cosmic microbial living systems from one cosmic habitat to another. With the 100 or so habitable planets that are now known to exist in our galaxy alone transfers of cometary dust carrying life including fragments of icy planetoids/asteroids would be expected to occur on a routine basis. It is thus easy to view the galaxy as a single connected "biosphere" of which our planet Earth is a minor component. The Hoyle-Wickramasinghe Panspermia paradigm provides a cogent biological rationale for the actual widespread existence of Lamarckian modes of inheritance in terrestrial systems (which we review here). Thus the Panspermia paradigm provides the raison d'etre for Lamarckian Inheritance. Under a terrestrially confined neoDarwinian viewpoint such an association may have been thought spurious in the past. Our aim here is to outline the main evidence for rapid terrestrial-based Lamarckian-based evolutionary hypermutation processes dependent on reverse transcription-coupled mechanisms among others. Such rapid adaptation mechanisms would be consistent with the effective cosmic spread of living systems. For example, a viable, or cryo-preserved, living system traveling through space in a protective matrix will of necessity need to adapt rapidly and proliferate on landing in a new cosmic niche. Lamarckian mechanisms thus come to the fore and supersede the slow (blind and random) genetic processes expected under neoDarwinian Earth centred theories.

Experiments to prove continuing microbial ingress from Space to Earth.

A wide range of evidence for pointing to our cosmic origins is close to the point of being overwhelming. Yet the long-entrenched paradigm of Earth-centered biology appears to prevail in scientific culture. A matter of crucial importance is to carry out a decisive experiment that is long overdue-establishing empirically beyond any doubt that extraterrestrial microbiota reaches the surface of the Earth at the present day. Such an experiment may of course happen naturally by the appearance of pandemics of new disease as discussed in an earlier chapter.

The sociology of science and generality of the DNA/RNA/protein paradigm throughout the cosmos.

The theory of cometary panspermia argues that life cannot have originated on Earth in the time available. It must have an ultimate, but still undiscovered cosmological source. The origin of life remains an open question. Life on Earth was introduced by impacting comets, and its further evolution was driven by the subsequent acquisition of cosmically derived genes. Explicit predictions of this theory stating how the acquisition of new genes drives evolution, are compared with recent developments in relation to horizontal gene transfer, and the role of retroviruses in evolution. Precisely stated predictions of the theory of cometary panspermia are shown to have been verified.

Cometary panspermia and origin of life?

A range of astronomical observations are shown to be in accord with the theory of cometary panspermia. This theory posits that comets harbor a viable biological component in the form of bacteria and viruses that led to origin and evolution of life on Earth. The data includes (1) infrared, visual and ultraviolet spectra of interstellar dust, (2) infrared spectra of the dust released from comet Halley in 1986, (3) infrared spectra of comet Hale-Bopp in 1997, (4) near and mid-infrared spectra of comet Tempel I in 2005, (5) the discovery of an amino acid and degradation products attributable to biology in the material recovered from the Stardust Mission in 2009, (6) jets from comet Lovejoy showing both a sugar and Ethyl alcohol and finally, (7) a diverse set of data that has emerged from the Rosetta mission. The conjunction of all the available data points to cometary biology and interstellar panspermia as being inevitable.

Lamarck and Panspermia - On the Efficient Spread of Living Systems Throughout the Cosmos.

We review the main lines of evidence (molecular, cellular and whole organism) published since the 1970s demonstrating Lamarckian Inheritance in animals, plants and microorganisms viz. the transgenerational inheritance of environmentally-induced acquired characteristics. The studies in animals demonstrate the genetic permeability of the soma-germline Weismann Barrier. The widespread nature of environmentally-directed inheritance phenomena reviewed here contradicts a key pillar of neo-Darwinism which affirms the rigidity of the Weismann Barrier. These developments suggest that neo-Darwinian evolutionary theory is in need of significant revision. We argue that Lamarckian inheritance strategies involving environmentally-induced rapid directional genetic adaptations make biological sense in the context of cosmic Panspermia allowing the efficient spread of living systems and genetic innovation throughout the Universe. The Hoyle-Wickramasinghe Panspermia paradigm also developed since the 1970s, unlike strictly geocentric neo-Darwinism provides a cogent biological rationale for the actual widespread existence of Lamarckian modes of inheritance - it provides its raison d'être. Under a terrestrially confined neo-Darwinian viewpoint such an association may have been thought spurious in the past. Our aim is to outline the conceptual links between rapid Lamarckian-based evolutionary hypermutation processes dependent on reverse transcription-coupled mechanisms among others and the effective cosmic spread of living systems. For example, a viable, or cryo-preserved, living system travelling through space in a protective matrix will need of necessity to rapidly adapt and proliferate on landing in a new cosmic niche. Lamarckian mechanisms thus come to the fore and supersede the slow (blind and random) genetic processes expected under a traditional neo-Darwinian evolutionary paradigm.