Bean and Young had a ball the rest of the sim giving those call signs, but that only lasted one day.
Conrad, as you might suspect, never used the language in an insulting way or even to curse something — he was a very friendly and funny man. Remember them? The LEM was Intrepid.
I said no. I did not meet any true blue fans in NASA till years later. I desperately wanted to see it opening night but was not able to wangle a ticket. The next week around the coffee pot in building 5 Buzz was there talking to the Apollo 11 backup crew Lovell, Anders, and Haise. I was not surprised that Buzz was an SF reader. Alan Andres told me that Buzz said he was tired from training that day and that he slept through most of the movie… still I think Buzz caught enough to know a good answer. I swear I heard this conversation in April of I am sure Buzz does not remember it.
The idea was that mass extinctions on Earth recur on a timescale of between 20 and 40 million years, and that this recurrence could be accounted for by the existence of a faint star in a highly elliptical orbit of the Sun. Put this object on a 26 million year orbit and it would, so the theory ran, destabilize Oort cloud comets, causing some to fall into the inner system at a rate matching the record of extinctions.
Thus a cometary bombardment was to be expected on a regular basis, as were the mass extinctions that were its consequence. No one has found Nemesis, though other theories about recurring mass extinctions are in play, including recent work from Lisa Randall and Matthew Reece that explores dark matter as the trigger, with the Sun periodically passing through a disk of the stuff. Of course, finding dark matter itself continues to be a problem. Moreover, the wide range in the proposed recurrences gives rise to the possibility that these events are not periodic at all but simply random.
Robert Zubrin now offers a paper arguing that random encounters between our Solar System and passing stars can account for the Oort Cloud disruptions leading to extinctions without the need for Nemesis. Appearing in the International Journal of Astrobiology , the paper weighs other discussions of periodicity and goes on to propose a model for calculating the frequency of these encounters.
The model rides on the treatment of the galaxy as a gas, with stars as particles at a density of approximately 0. These stars, argues Zubrin, are clearly not in synchronized motion but have random velocities with respect to each other on the order of 10 kilometers per second. Much rides on the effective encounter distance — when do stars pass closely enough to disrupt the outer cometary shell?
Image : The layout of the solar system, including the Oort Cloud, on a logarithmic scale. We also have to take into account that the Sun is among the larger stars, the most common type of encounter being with far less massive M dwarfs. Zubrin assumes such stars have Oort Cloud analogs of their own, though we have as yet no observational evidence for this. Assuming 4 Oort cloud objects per cubic AU, this implies that approximately 25, alien cloud objects could potentially be captured per pass, providing a significant chance of impact events to follow.
By the calculations of this paper, while we might expect bombardments on the order of 30 million years or so in our system, our Oort Cloud would be delivering bombardments to a passing dwarf star every 7. Crucially, these events, transferring objects from one system to another, could happen fairly swiftly. Note that Zubrin derives the figure of 10 AU for the distance a visiting star needs to come to an Oort Cloud object to turn it into a comet; i.
If we estimate that each Oort Cloud object disrupted has an average mass of 1 billion tons, then an encounter [with a star] at 20, AU would appear to have the potential to import about 25 trillion tons of mass from another solar system into our own. Of course, only a tiny fraction if it would hit the Earth.
But even so, the potential to transfer biological material is evident. Most of these bombardments of our own system would occur from M-dwarf comet clouds, given the high percentage of M-dwarfs in the galaxy. The table below shows the distribution. Table 1. Comparative responsibility of star types for cometary bombardment of our Solar System.
Credit: Robert Zubrin. Notice that Zubrin is talking about microbes in the transferred material that would have to survive a journey far less than the multiple light years assumed necessary for interstellar panspermia, though they would have to survive Oort-like conditions, having traveled from their inner system to the comet cloud. It may also be noted that with a typical time between incoming encounters of 25 million years, it is probable that our Solar System has had about incoming-delivery encounters with other stars since life first appeared on Earth some 3.
But, as a large G star, the sun probably delivered at least three times as many bombardments on other stellar systems as it received. Our star keeps orbiting galactic center somewhere in the range of every to million years. A lot of material could be exchanged in this way:.
If each of these were then to act as a similar microbial transmitter, the result would be billions of inhabited worlds seeded by Earth. More frequent impacts might actually be a useful evolutionary driver — the author notes that the biosphere recovered from the K-T impact within 5 million years, offering up mammals and birds that proved long-term survivors.
But too frequent an impact rate would not allow sufficient recovery time. Thus it is conceivable that areas of the galaxy with perhaps double our population of stars might be those more likely to feature advanced species and civilizations.
Harvesting objects from passing stars, most of them red dwarfs, we collect them on timescales of years or decades rather than millions of years, the result of their relatively close disruption. We wind up with a mechanism for exchanging materials with other stellar systems that could have implications for life. A key question: Can life survive Oort-like conditions to allow such transfers? In such ways does a speculative astrobiology sharpen its focus, within a process of scientific inquiry that is by necessity multi-generational. Now we have a group of 14 astronomers, European as well as American, who have assessed the available data from all angles.
It considers the question of whether the extraterrestrial spacecraft hypothesis is supported by examination of all the peer-reviewed work that has thus far appeared. This cross-pollination led to the first comprehensive analysis and the best big-picture summary to date of what we know about the object.
We tend to assume that the physical processes we observe here, close to home, are universal. The inset shows a color composite produced by combining images obtained through three visible and two near-infrared filters totaling 1. To see full text of the paper, see this link thanks Alex Tolley for an alternate link!
On the specific question of alien technologies, the paper has this to say:. For a solar sail to cause the observed non-gravitational acceleration, it needs to remain properly oriented towards the Sun. However, to yield the observed brightness variations, its orientation would need to be varying as viewed from Earth. It has not been shown that an orientation exists that can achieve all of these constraints imposed by the observational data.
The Spitzer observations are consistent with geometric albedos 0. While provocative, this argument is baseless.
Second, the measured number density cannot be claimed to be at odds with expectations because of our ignorance of the size distribution of interstellar objects. All report anticipating results from the Large Synoptic Survey Satellite LSST , which comes online in and may give us more interstellar objects of the same kind, allowing a deeper and perhaps less controversial analysis. The paper is Bannister et al.
Archived from the original on He portrays Londo, and other characters with such a deft hand that I can hear the actors speaking his written dialogue. Dana Marie Bell. As a male lead, Garrick, is a pretty good character as well. If you'd like to get the additional items you've selected to qualify for this offer, close this window and add these items to your cart. These stories are still lively today, and recall a time when the members of the British Interplanetary Society and science fiction fans met regularly at such venues. Casey's Warriors.
The latest find from TESS, the Transiting Exoplanet Survey Satellite, is a reminder of how interesting, and useful, a planetary system can be even if we find no Earth-like worlds there. One Venus, hellish as it is, would seem to be enough. We still have many questions about why Earth became habitable and Venus did not. If we can find and study similar examples around other stars, like L , we can potentially unlock some of those secrets. What we have at L could conceivably become a primer in atmospheric transformation. The primary is an M-dwarf about a third the mass of the Sun, found 35 light years away in the constellation Volans.
Here we have a 2. Moving outward, we find L c, about 1. The furthest planet found so far is L d, about 1. TESS will observe L in enough sectors that it may be able to detect planets with orbits around days. But if we get really lucky, we might see the gravitational effects of undiscovered planets on the ones we currently know.
The paper points out that these worlds are too small to retain atmospheres rich in hydrogen, so the focus will be on secondary atmospheres that are the result of volcanic activity, and infalling volatiles from the rest of the system via comets. The authors calculate that all three planets are in range for JWST to produce a transmission spectrum showing atmospheric features.
The expected signal-to-noise ratio compares to another nearby red dwarf planet, GJ b. Understanding why Earth is habitable and Venus is not will depend upon our analysis of planets that have evolved through the greenhouse phase. In this regard, the L planets stand out, particularly since other Venus analogs thus far discovered orbit fainter stars.
From the paper:. This is a region where the atmosphere of a planet like Earth would likely have been forced into a runaway greenhouse, producing conditions similar to those found on Venus. The range of incident fluxes within the Venus Zone corresponds to insolations of between 1—25 times that received by the Earth.
Planets in the Venus Zone that can be spectroscopically characterized will become increasingly important in the realm of comparative planetology that aims to characterize the conditions for planetary habitability. In that respect, and considering the potential for atmospheric characterization…, L could become a benchmark system. What we know of these worlds will be refined by future TESS observations, possibly uncovering other planets here and monitoring activity on the host star. The paper is Kostov et al. We can anticipate launch in and arrival at Titan in , with a craft that will sample surface organics and examine prebiotic chemistry and potential habitability.
We are beyond excited for the chance to explore and see what awaits us on this exotic world.