Dr Ian KempNothing could be more boring than a rock going round in orbit for mill ions of years, right? Well as usual, Ian begs to differ, and will take you on a quick tour of some of the features of orbits that you may not have com e across before.
The elliptical orbit under the influence of gravity
was solved theoretically by Isaac Newton in the 1600s, and his equations ar
e usually used today, to calculate orbits of planets, moons, comets, near-E
arth asteroids, and spacecraft. There are only two slight problems - firstl
y, the equations cannot actually be solved if there are more than two bodie
s involved (which is usually the case, eg. Earth-Moon-Spacecraft); and seco
ndly the equations are actually incorrect anyway because they don't include
time dilation due to velocity and gravity. The only way to understand orbi
ts long term is to use supercomputer modelling.
In this talk we
will quickly run through some of the consequences of the 'three body probl
em' and the limitations of Newton's model of gravity. Orbit swaps, drastic
variations in Earth's orbit round the Sun, and the underlying chaotic natur
e of orbits in general. The fact that all orbits are inherently unstable op
ens up an interesting question.... could another body share Earth's orbit?
If so, how could it get there? And if not, why not? Ian will outline some o
riginal research into whether there might be something very interesting lur
king at one of the Earth-Sun Lagrange points.
As a finale we wi
ll look at orbits in the framework of general relativity - and find out if
this makes things easier, or harder to understand.
Dr Ian KempI started my working life in the UK steel industry. After gaining a 1st class honours degree and PhD in Metallurgy a t the University of Leeds, I pursued an academic career initially at the Un iversity of Wales, then at the BHP Melbourne Research Laboratories in Melbo urne, Victoria. During this period I achieved a number of Journal publicati ons and Conference Presentations in the field. I later moved into more appl ied work in Steel Processing, Data Management and Technology Deployment, in industries including Steel manufacture, government, and Oil & Gas. The latter included two years in the Pilbara (NW Australia) managing a range o f process improvement projects. In my later career my focus was on Project Management though I maintained a technical focus and was awarded a patent r elevant to reducing the environmental impact of offshore operations.
Through all this time I maintained an interest in astronomy, and gained a G raduate Diploma and Masters Degree in Astronomy from Swinburne University ( Victoria) by distance learning.
I recently joined ICRAR as a full tim e researcher after many years as an enthusiastic amateur astronomer. I am p ursuing a number of smaller projects as I discover where my main research i nterests lie. A couple of my research areas are extensions to short project s carried out for my Masters Degree in Astronomy.
DATA INTENSIVE ASTR
ONOMY
Developing standardised data flows to process the large flow of
data from the new FAST radio astronomy dish in Southwest China.
CATAC
LYSMIC VARIABLE STARS
I am studying a type of variable star known as U
GSU, which consists of a binary system in which a medium-sized red star orb
its a more massive white dwarf. These are the precursor systems to the &lsq
uo;type 1a supernovae’, which are very important phenomena in Astrono
my In these systems the red companion spills matter onto the white dwarf, c
reating an accretion disk. From time to time the disk becomes gravitational
ly unstable and collapsed onto the WD, causing the system to brighten by a
factor of 10,000 or so. By studying the light emitted during this collapse
we can learn about the behaviour and possible ultimate destruction of the s
ystem.
EARTH’S TROJAN POINTS
It is possible for asteroids,
rocks, and dust to share Earth’s orbit, if they can become bound to
one of the ‘Lagrange Points’ which sit ahead of and behind Eart
h in its orbit. My work based on dynamical modelling using the Swinburne su
percomputer has established the criteria for large objects to maintain a st
able ‘tadpole’ or ‘horseshoe’ orbit as a partner of
Earth. I am extending this work to look at the possibility of primordial g
as and dust being retained – for these small particles the models nee
d to include the effects of radiation pressure and light drag.
EVOLUT
ION OF ‘GREEN VALLEY’ GALAXIES
I am investigating the evol
ution of galaxies as they transition from the blue cloud to the red sequenc
e (if in fact they do transition!) – specifically looking for correla
tions with the gas content of the galaxies. This work is under the directio
n of Ivy Wong and Barbara Catinella at ICRAR.
Nothing could be more boring than a rock going round in orbit for mill ions of years, right? Well as usual, Ian begs to differ, and will take you on a quick tour of some of the features of orbits that you may not have com e across before.
The elliptical orbit under the influence of gravity
was solved theoretically by Isaac Newton in the 1600s, and his equations ar
e usually used today, to calculate orbits of planets, moons, comets, near-E
arth asteroids, and spacecraft. There are only two slight problems - firstl
y, the equations cannot actually be solved if there are more than two bodie
s involved (which is usually the case, eg. Earth-Moon-Spacecraft); and seco
ndly the equations are actually incorrect anyway because they don't include
time dilation due to velocity and gravity. The only way to understand orbi
ts long term is to use supercomputer modelling.
In this talk we
will quickly run through some of the consequences of the 'three body probl
em' and the limitations of Newton's model of gravity. Orbit swaps, drastic
variations in Earth's orbit round the Sun, and the underlying chaotic natur
e of orbits in general. The fact that all orbits are inherently unstable op
ens up an interesting question.... could another body share Earth's orbit?
If so, how could it get there? And if not, why not? Ian will outline some o
riginal research into whether there might be something very interesting lur
king at one of the Earth-Sun Lagrange points.
As a finale we wi
ll look at orbits in the framework of general relativity - and find out if
this makes things easier, or harder to understand.
Dr Ian KempI started my work ing life in the UK steel industry. After gaining a 1st class honours degree and PhD in Metallurgy at the University of Leeds, I pursued an academic ca reer initially at the University of Wales, then at the BHP Melbourne Resear ch Laboratories in Melbourne, Victoria. During this period I achieved a num ber of Journal publications and Conference Presentations in the field. I la ter moved into more applied work in Steel Processing, Data Management and T echnology Deployment, in industries including Steel manufacture, government , and Oil & Gas. The latter included two years in the Pilbara (NW Austr alia) managing a range of process improvement projects. In my later career my focus was on Project Management though I maintained a technical focus an d was awarded a patent relevant to reducing the environmental impact of off shore operations.
Through all this time I maintained an interest in a stronomy, and gained a Graduate Diploma and Masters Degree in Astronomy fro m Swinburne University (Victoria) by distance learning.
I recently jo ined ICRAR as a full time researcher after many years as an enthusiastic am ateur astronomer. I am pursuing a number of smaller projects as I discover where my main research interests lie. A couple of my research areas are ext ensions to short projects carried out for my Masters Degree in Astronomy.
DATA INTENSIVE ASTRONOMY
Developing standardised data flows to pr
ocess the large flow of data from the new FAST radio astronomy dish in Sout
hwest China.
CATACLYSMIC VARIABLE STARS
I am studying a type of
variable star known as UGSU, which consists of a binary system in which a m
edium-sized red star orbits a more massive white dwarf. These are the precu
rsor systems to the ‘type 1a supernovae’, which are very import
ant phenomena in Astronomy In these systems the red companion spills matter
onto the white dwarf, creating an accretion disk. From time to time the di
sk becomes gravitationally unstable and collapsed onto the WD, causing the
system to brighten by a factor of 10,000 or so. By studying the light emitt
ed during this collapse we can learn about the behaviour and possible ultim
ate destruction of the system.
EARTH’S TROJAN POINTS
It is
possible for asteroids, rocks, and dust to share Earth’s orbit, if t
hey can become bound to one of the ‘Lagrange Points’ which sit
ahead of and behind Earth in its orbit. My work based on dynamical modellin
g using the Swinburne supercomputer has established the criteria for large
objects to maintain a stable ‘tadpole’ or ‘horseshoe&rsqu
o; orbit as a partner of Earth. I am extending this work to look at the pos
sibility of primordial gas and dust being retained – for these small
particles the models need to include the effects of radiation pressure and
light drag.
EVOLUTION OF ‘GREEN VALLEY’ GALAXIES
I a
m investigating the evolution of galaxies as they transition from the blue
cloud to the red sequence (if in fact they do transition!) – specific
ally looking for correlations with the gas content of the galaxies. This wo
rk is under the direction of Ivy Wong and Barbara Catinella at ICRAR.