Some of you may have read a book or seen a film called The 39 Steps. The title of this talk is similar, but that is where the similarity ends.
I shall begin by talking about the smallest things discovered in the universe, sub - atomic particles, then go up step by step with ever larger bodies, eventually getting to
the stars, galaxies and whole universe. Each step will be 10 times the size of the previous one and objects 10 times greater. And 10 times linear dimensions can mean 1000 times volume.
Most people are familiar with astronomical sized numbers by giving them in the form of power of 10. To make sure I’ve listed some typical numbers in this form with their full equivalents. You will notice that the power number always equals the number of noughts, and that a minus sign is used for very small numbers.
10 to the power of 3 = 1000.
10 “ 6 = 1000,000.
10 “ 12 = 1000,000,000,000.
10 to the power of 1 = 10.
10 “ 0 = 1.
10 “ -1 = 1/10.
10 “ -3 = 1/1000.
10 “ -6 = 1/ 000,000.
Right then, a non-stop action sequence starting at the bottom.
STEP 1. Anything smaller than 10 to the power of 10 -13, which is smaller than 10 million millionths of a centimetre.
It includes all the sub-atomic particles, ie the individual parts of the nucleus along with many other varied particles. These were discovered using cloud chambers and bubble chambers, the latter being full of simmering liquid hydrogen. Do you remember the cloud chamber brought in here, and the one made by J Tasker ? (Bubble chamber slide). Lines of condensed vapour or bubbles are produced in these chambers by atomic and sub-atomic particles. They may be small but there are so many they make a big subject, as you will notice in the next three slides. (A Particle Tree slide, a Magfield slide, and one other). You see that, as well as protons and neutrons, there are neutrinos, baryons, gravitrons, hadrons, mesons, muons, kaons, pions, quarks, and onwards, to mention less than half of them.
Neutrinos have been detected using this neutrino telescope, with a tank of dry-cleaning fluid, buried in a mine in the United States. [Neutrino slide] Gravity waves (gravitrons) have been found using this ‘gravity telescope’. (Gravity slide).
STEP 2. In this step the diameters of complete atomic nuclei range from 10-13cm for the smallest, hydrogen, and about 10-12cm for heavy elements nuclei. (Possible atom slide). The diameter of the electron also falls in this range being 5.6 x 10-13 across. Also the nuclei and electrons which make up the lion’s share of cosmic rays.
STEP 3. 10 to the power of -12 to 10-11cm.
Here we have the shortest wavelength, high frequency, rays. Very penetrating radiation produced during nuclear reactions, and forming part of the cosmic radiation from space.
STEP 4. 10-11 to 10-10cm,.
The wavelength of typical gamma rays extends throughout this range.
STEP 5. 10-10 to 10-9cm.
The longest wavelength of the gamma rays is about 10-9cm. Although mild by gamma ray standards this is still very dangerous radiation.
STEP 6. 10-9 to 10-8cm.
X-rays take over from gamma rays when the wavelength exceeds 10 to the power of 9cm. X-rays can be made by allowing cathode rays (electrons) in a discharge tube to fall on a metal plate within the tube (Discharge tube slide). The wavelength of the X-rays varies with the metal used.(Hospital X-ray slide). There are also well known X-ray sources in space.(X-ray slide of …)[ word indecipherable].
STEP 7. 10 to the power of -8 to 10-7.
The diameters of atoms fall within this step, atoms of course being not only the atomic nucleus and electrons but also the orbital paths followed by the electrons, the orbits taking up most of the room. (Gold atom slide).
As the nucleus is about 10-13cm across, and the whole atom is 10-8 across, the atomic diameter is 100,000 tines that of the nucleus. Scaled up, if the atom is imagined to be 100 yards across, then the nucleus and electrons would be the size of grains of sand, and everything else within the 100 yards simply empty space. The Angstrom unit, 10-8cm, is sometimes used for measuring wavelengths in this step.
STEP 8. 10-7 to10-6.
With this step we reach the size of simple molecules - combinations of atoms such as H2 0, Fe2 O3, C2 H5 OH.
STEP 9. 10-6 to 10-5cm.
The size of complex organic molecules, which range from a millionth to a hundred thousandth of a centimetre. At this wavelength X-rays give way to ultra-violet radiation. This radiation, as supplied by the Sun, is only partially blocked by the atmosphere, and causes sunburn. (Pin-up beach slide).
STEP10. 10 to power of 5 to 10 to power of 4cm.
Ultra-violet up to wavelength 4 times 10-5cm (violet). Visible to 8 times 10-5cm (red). Above 8 times 10-5 we get infra-red.
STEP 11. 10-4 to 10-3cm.
A hundredth to a thousandth of a centimetre. ( It represents the limitation of useful magnification in the ordinary optical microscope). It includes the wavelength of infra-red radiation which can be detected in space, even from non luminous bodies. Infra-red
photography from satellites is used because it can penetrate cloud. (Infra-red satellite slides). Here is a shot giving a satellite view, and a much rarer view at ground level using infra-red film. Notice the red vegetation.
STEP 12. 10-3 to 10-2cm.
One hundredth to one tenth of a millimetre, typical of the size of micro-meteorites. Infra-red radiation gives way to microwaves at these wavelengths.
STEP 13. 10-2 to 10-1cm.
One tenth to one millimetre. The wavelengths of radar, radio and TV waves start here. A typical meteor as seen on meteor watches would be of this size, as is a grain of coarse sand. The jar of sand I have with me contains about a million grains of sand.
STEP 14. 1 millimetre to 1 centimetre.
A meteor within this range would be a very bright one.
STEP 15. 1 cm. to 10 cms.
Meteors this size would give a brilliant fireball and often survive the descent to Earth, as has the specimen I have here.
STEP 16. 10 cms to 1 metre.
(This square section of bench is about a cubic metre in size). The first satellite, Sputnik 1, was 60 to 70 cms across, a Russian triumph of 1957. Some 6 months later, and with some difficulty, the United States got a 10 to 12 cm ‘grapefruit’ into orbit ( Explorer ).
Human beings fall into this volume range, and while usually over 1 metre tall they are always under 1 metre front to back and side to side. Even me !
STEP 17. 1 metre to 10 metres.
The largest meteorite in captivity, now in the American Hayden Planetarium, N.Y. It was found in Greenland by E. Peary in 1897, and weighs 30 tons.
The size of the mirrors of the largest telescopes are within the range of step17.
4 m., Siding Springs, Australia. 5 m., Palomar, USA. 6 m., Urals, USSR. (Slide.)
STEP 18. 10 metres to 100 metres.
The meteorite that blasted out Meteor Crater in Arizona would have been in this category, being about 70 metres across.
STEP 19. 100 metres to 1000 metres.
The very smallest asteroids could be up to 1000 m. across. (Slide). Associated with space perhaps this ‘step’ could include the worlds largest radio telescope, 300 m. across, at Arecibo, Puerto Rico. Or even the Apollo Saturn rockets, 120 m. high.
STEP 20. 1 to 10 kms.
The nucleus of a small comet would come into this category. So might the Arizona meteor crater, being 1300 metres across.
STEP 21. 10 to 100 kms.
This would include the head of the average comet, the size of the average asteroid, and the diameters of Neutron Stars, (Slide, comet ).
STEP 22. 100 to 1000 kms.
This includes the height of Aurorae - 100 to 300 kms. The convection cell in the Sun’s photosphere - 500 to 1000 kms., and the largest asteroids, Ceres, Pallas, Juno, Vesta. (Asteroid slide).
STEP 23. 1000 to 10,000 kms.
The diameter of the Moon, 3,500 kms.
The diameter of Mercury, 4,800 kms.
The diameter of Mars, 6,600 kms.
Also within this range are the main satellites of Jupiter. (Jupiter satellites slide).
STEP 24. 10,000 to 100,000 kms.
The diameter of Earth, 12,700 kms.
The diameter of Uranus, Neptune, 45,000kms. (Slide).
Jupiter Red Spot, 12,000 x 50,000 kms.
Typical white dwarf, diameter 20,000 to 50,000 kms.
Typical solar flare, 50,000 to 100,000 kms.
STEP 25. 100,000 to 1,000, 000 kms. ( 10-5 to 10-6 km.)
The distance light travels in one second, 300,000 kms. (Describe light progress).
The diameter of Saturn, 120,000 kms.
The diameter of Jupiter, 142,000 kms. (Jupiter slide).
Earth to Moon distance, 380,000 kms.
Closest recent asteroid approach : Hermes, 1937, at 780,000 kms.
STEP 26. 1 million to 10 million km.
The diameter of the Sun is 1,390,000 km, a distance of four and a half light seconds.(Sun slide).
The closest approach of some ‘near miss’ comets have been under 10 million kms., eg., in 1770 Lexell’s comet came within 2.4 million kms of the Earth.
STEP 27. 10 million to 100 million kms.
The closest approach to Earth by Venus is 40 million kms..
The closest approach to Earth by Mars is 60 million kms.
The Mercury to Sun distance is 60 million kms.
STEP 28. 100 million to 1000 million kms.
The average Earth to Sun distance is about 149,597,892 kms., and this is one Astronomical Unit, which = 500 light seconds.
Jupiter to Sun distance is 800 million kms.
The diameter of Betelgeuse is 450 million kms.
STEP 29. 1000 million to 10 thousand million kms.
Saturn to Sun distance, 1400 million kms.
Neptune to Sun distance, 4400 million kms.
Pluto to Sun distance, 4000 million to 5000 million kms.
STEP 30. 10 to power of 10 to 10 to power of 11 kms.
These distances are the limits of the outer orbits of ‘regular’ comets.
STEP 31. 10-11 to 10-12 kms.
The region of the solar system where ‘one time’ or ‘one visit only’ comets came from. Periods for these comets may be millions of years.
STEP 32. 10-12 to 10-13 kms.
One light year is 9.4 x 10 to the power of 12, so as a reasonable approximation it is given as 10 to the power of 13 kms., 2000 times the distance of Pluto.
STEP 33. 1 LightYear (a LY) to 10 LightYears (10- 13 to 10-14 kms.).
3.26 LY is 1 Parsec, the distance at which 1 A.U. subtends an angle of one second of arc. The distance is 206,265 A.U. Scaled down, if 1 A.U. were 1 centimetre the distance would be 2.06 kilometres. (Slide).
Within 10 LY we find the nearest stars:-
Centuri (A, B, C.), distance 4.3 LY.
Barnards Star distance 6.0 LY.
Sirius distance 8.7 LY.
There are only about 12 stars within 10 LY and these include 1b triple and 3 doubles.
STEP 34. 10 LY to 100 LY.
Within this distance range we have :-
Lyne, Vega. 27 LY.
Bootes, Arcturus. 33 LY.
Aungae, Capella. 42 LY. (Slide).
Tauri[?], Aldebaran. 53 LY.
Leonis, Regulus. 67 LY.
All familiar friends of the observer.
32.6 LY = 10 parsecs = the distance to which stars are mathematically taken to give their absolute magnitudes.
Whereas the last step, 33, had a dozen stars, within this one around 3000 stars are known, and there are almost certainly undiscovered ones.
STEP 35. 100 to 1000 LY.
More well known stars and distances :-
Betelgeuse. 650 LY. (Slide of Betelgeuse).
Rigel. 650 LY. (Slide of Rigel).
Scorpu, Antares. 250 LY.
Cigni, Deneb[?]. 540 LY.
Canra[?], Canopus. 180 LY.
Other less well known stars within 1000 LY would total millions.
The diameters of the extra galactic globular clusters would also be 100 to 1000 LY.
STEP 36. 1000 to 10,000 LY.
Orion nebula, 1600 LY distant.
Crab nebula, 3300 LY distant. (Crab slide).
The thickness of the Milky Way galaxy from our position, near the edge, would be about 1000 LY.
STEP 37. 10,000 LY to 100,000 LY.
The distance to extra galactic globular clusters (slide) is about 10,00 to 35,000 LY. The best direction for them is in Sagittarius.
STEP 38. 100,000 LY to 1,000,000 LY.
The distance to the nearest ‘outside’ galaxies, the magellanic clouds, 150,000 LY.
(Magellanic cloud slide).The diameter of the Milky Way galaxy across disc (Slide), is 100,000 LY and more. The total number of stars are 10 to the power of 11 to 10 to the power of 12.
STEP 39. 1,000,000 LY to 10,000,000 LY.
The distance to Andromeda, M31, galaxy is 1.5 million LY, as is that to M33, in Trangulum [?]. (Andromeda slide).
Within 3.3 million light years we have the above mentioned galaxies, our own Milky Way, and 18 various irregular dwarf galaxies, including the Magellanic clouds. This collection of 21 galaxies is the local group.
We think of local as the parish pump, the corner shop, and perhaps the nearest hostelry, but in the situation discussed ‘local’ is the sort of distance where it has taken light 3 million years to reach us.
STEP 40. 10 million to 100 million LY.
We now have not mere groups, but clusters of galaxies eg. the Virgo cluster (Slide) containing some 2500 galaxies, and which are 50 to 100 million LY distant. There are also individual galaxies such as one in Corra[?] Berenices, approximately 60 LY away.
STEP 41. 100 million to 1000 million LY.
Yet more galaxy clusters are even further out. The Corra[?] Berenices cluster of 1000 galaxies (Slide) extends out to 250 million LY. The Hercules cluster of 2900 galaxies to 325 million LY, and the Corona cluster to 650 million LY.
STEP 42. 1000 million to 10,000 million LY.
The light from objects this far takes as long as the Earth took to form from start to finish, say 4,600 million years. What are these objects then? Yet more galaxies and clusters of galaxies. A cluster in Hydra is 2000 million LY distant. (Hydra slide).
We now start to run into the quasars, of which about 150 have been found to date. Quasar 3C 273 was the first recognised as such. It is 1500 million LY away, according to Hubble’s Red Shift law, and emits 100 times the energy of a whole galaxy. (Quasar slides).
Another quasar, 3C 9 is receding at 80% of the speed of light, is 8000 million LY away and has 1000 times the energy output of a whole galaxy. (Slide with graph of quasar distances).
STEP 43. 10,000 million to 100,000 million LY.
This was to be the last step, hence the title of the talk. Yet, while an entry in the 1978 Guinness Book of Records gives the remotest object as a quasar, OQ172, as being 15,600 million LY away, another book notes that 4C 534 is 30,000 million LY
distant. This quasar, studied at Kitt Peak, has, according to red shifts, a recession of 87% the speed of light.
So now we come to the final STEP 44. Any thing over 100,000 million LY.
Everything mentioned in the previous steps has been measured using conventional large telescopes and appropriate gadgetry. However, on the way is the giant space telescope. Being of equivalent optical performance to ground based observatories, but above the atmosphere, it will have the resolving power at least 10 times the best telescopes we currently possess.
Logically, if ‘ordinary’ telescopes can measure an object at 15.900 million LY, then this instrument will record objects at 10 times the distance - quasars at 100,000 million LY, and more.
If we assume that is the furthest we will ever see in our lifetimes then, to give an idea of scale, we can reduce it as follows :-
If 1 million light years is reduced in scale to 1 millimetre, ie. if the distance from us to Andromeda is given as a grain of coarse sand, then at this scale, 100,000 million LY would be equal to100 metres. Assuming 1 galaxy per 1 million light years, this would mean as many galaxies as there would be grains of sand filling a volume of 100 cubic metres! And each galaxy will be full of millions of stars…..
So concludes my talk of the 43 steps. Do say if you think I have left anything out.