> Is Nemesis an asteroid?
Nemesis is asteroid # 128. It was discovered in 1872. It is one of the main
belt asteroids, with a period of about 4 and a half years. The perihelion is
in Aries, which is the most common for asteroids.
> Nemesis is asteroid # 128.
I like its number, because as an old 8-bit programmer, 128 has special meaning
as the value of the highest bit.
> It was discovered in 1872. It is one of the main belt
> asteroids, with a period of about 4 and a half years.
> The perihelion is in Aries, which is the most common
> for asteroids.
I didn't know that! Are there any theories as to why that is? It seems very
interesting.
Michael Rideout
I had noticed that 128 is a power of 2...
As for the concentration of perihelia in Aries: when I first noticed it
(imported a long list of orbital elements into Excel and did a chart) I thought
it must be a mistake. I asked a question on sci.astro and never got any
responses.
Later, however, here is what I found from Eleanor Bach:
"Jupiter then exerts a pull art that body and disturbs its orbit. Jupiter
therefore is responsible for two very striking conditions in the Asteroid belt,
gaps and groups. The gaps (Kirkwood's Gaps, first pointed out by Daniel Kirkwood
of Indiana University in 1866) occur when the relative orbits of Jupiter and the
smaller bodies are commensurable, that is when the ratio of the mean orbital
motion of the minor planets to that of Jupiter is a simple fraction- 3/1, 5/2,
7/3, 2/1, etc. Repeated attractions by Jupiter eventually pull the small bodies
out of these positions and gaps are created. The gaps in the Asteroid belt are
similar to the gaps in the rings of Saturn which are caused by the pertubative
effects of Saturn's satellite Mimas (see Diagram I). Two of these gaps are the
Hecuba gap, with an orbital period half that of Jupiter. and the Hestia gap with
one-third of Jupiter's period. Groups, on the other hand, occur when the mean
motion is close to that of Jupiter. For example, when the critical ratio is 3/2
(type of the Asteroid Hilda), 4/3 (type of Thule), there are accumulations of
objects rather than gaps. The Hilda group consists of 19 Asteroids and no other
minor planets are to be found in the vicinity. Another factor pointing to
Jupiter's influence is this curious fact: The longitude of Jupiter's perihelion
is 13.5 degrees and Statistics show that a remarkable number of Asteroid orbits
also have perihelion longitudes concentrated close to that of the Jovian orbit.
In fact, three times as many Asteroids have their perihelion in the neighborhood
of this value compared with those which lie on or about Jupiter's aphelion."
(from http://www.speakeasy.org/~jondunn/ast/bach.html)
Jonathan Dunn
jon...@speakeasy.org
http://www.speakeasy.org/~jondunn/
> I had noticed that 128 is a power of 2...
Yep! It's also the value of the high bit (bit 7) in a single byte, and on an
8-bit processor-- such as the 6502-- it often indicates a *negative* (which
seems appropriate for Nemesis). That is, byte values from 0 to 127 have bit 7
in an "off" setting (a 0), and are often taken to be positive values, whereas
byte values from 128 to 255 have bit 7 in an "on" setting (a 1), and are often
treated as negative values. Of course, you could also treat them as positive
values, but in comparisons, bit 7 is the "negative flag."
I guess I should find out more about Nemesis, because it seems to be very
active in my chart, as I noted in an earlier post. I'm going to have to go
back and reread what you posted about it, and maybe do a bit of reading in the
mythology books!
According to one of my dictionaries, "nemesis" means "retributive justice," and
"a downfall caused by this," or "an agent of such a downfall." In Greek, it
means "righteous indignation, personified as goddess of retribution." The
dictionary entry also says that it's from "nemo"(!), meaning "give what is
due." I didn't realize that when I looked up the position of asteroid Nemo
(#1640) in my chart! I was just attracted to it because of Captain Nemo, whose
name now makes sense to me. Maybe I should take back what I said about feeling
an affinity for that character? ;-)
Michael Rideout