Curiosity has landed on the Martian surface to begin a two-year mission.
Curiosity survived a make-or-break descent and touched down within its landing zone. Curiosity beamed its first three images from the Martian surface, one of them showing a wheel of the vehicle. The car-sized rover came to rest at its planned destination near the foot of a tall mountain rising from the floor of Gale Crater in Mars' southern hemisphere. http://venitism.blogspot.com
The universe is accelerating, pushed outward by dark energy, a mysterious force
that acts in a way opposite to gravity. The vast scale of this unknown shook the
world of cosmology, the science of how the universe originated and developed.
Dark energy accounts for about 70 percent of all mass and energy in the
universe. Combined with dark matter undetectable particles with detectable
gravitational pull, that figure is 96 percent. Meaning: All we see and know in
the visible material realm, from stars to sand, makes up only 4 percent of the
universe.
We describe the "nearest" stars as being 2,000 light "years" away; the light
reaching us now left them back when humans were still fashioning flint
arrowheads here on Earth. The span of the Milky Way is, similarly, 100 thousand
light years across again, a measurement of distance expressed as a measurement
of time.
Many telescopes can allow us, on this basis, to see a distance reaching back
3,800 million years to a point when the Universe was only a third of the age
it is now. The very best can take us back to the beginning, and from this we
know that the Universe has been expanding since it was formed more than 13
billion years ago. Understanding what happened in between relies on a conception
of space and time's indivisibility which is roughly when things start to get a
bit strange.
A thing is also defined by the space it occupies. By saying
there is nothing here, I am saying that there is still a space and time here,
even though there is nothing. So nothing is not the same as
not anything. Not anything only happens when you take the space and time
away. Once you get your head round that little distinction, you're away.
Clearly aware that not everyone is of the same disposition, mathematicians have
given us the number zero to help us get the hang of the nothing/not anything
distinction. Zero, sometimes misunderstood as the bottom of the numerical chain, is of course in the center of it. On either side of zero, an endless string of positive and
negative numbers stretch endlessly away.
The same thing happens in space. Space is actually a fuzzy ball full of
energy. You are sitting on chairs which you think are hard, but
you know that if you look hard enough the chair is not a hard piece of plastic,
but a bunch of molecules with large gaps between them. This continues as we
delve ever further into the microscopic depths of any material until we reach
quarks most of any material is, in fact, nothing but a magnetic field of
positive and negative energy.
All of space is like that made up of stuff that's barely there. Between
elementary particles there is nothing except space-time, a balance between
positive and negative energy cancelling each other out. It is, effectively,
therefore, balanced at the zero point between positive and negative. But
locally, that means that within space-time a concentration of either positive or
negative energy can exist. If you get a lot of this locally, it can cause a bang
a very big one.
One such bang started our own Universe. Its beginning was therefore a small
fluctuation in a sea of nothing, when the time equalled zero. The heat and
debris that was produced following its explosion indicates that fast expansion
followed.
Once it started to cool, however, an unexplained defect was revealed. What
should have been half positive and half negative energy, or half matter and half
anti-matter, turned out to have slightly disproportionate allocations of the
two. There is, in fact, a one part in 1,000 excess of matter so while most
positive and negative particles met and cancelled each other out, forming heat
and radiation, a small quantity formed into what we see around us. We are all
the result of this defect.
It turns out that we are also a lot older than we think, at least in part. Most
of this early matter initially turned into hydrogen which means that the
hydrogen making the water in our bodies is about 13.7 billion years old. The
structure of the Universe then emerged as this matter fell into place, triggered
by shockwaves created by the sound of the Big Bang, that caused it to pile up.
Hydrogen, packed together at high temperatures, melted and formed into the next
most stable elements in the Universe; helium, carbon and oxygen. These were
cooked up inside stars.
The study both of the expanse of space-time and the tiny, elementary particles
which inhabit it, has since the last century allowed researchers to probe a
strange, quantum world of anomalies where the traditional laws of physics no
longer apply.
One of the early discoveries in this regard was that light behaves both as a
particle and a wave. The duality was understood by James Clerk-Maxwell, when in
the course of correcting equations for electro-magnetism he was able to show
that magnetic fields and electric fields create one another on a mutual basis,
and that light is a force that carries magnetic fields.
This does not answer the particle-wave paradox, but highlights the strangeness
of the world researchers have unveiled. The answer to whether light is a
particle or a wave is fundamentally yes. Nature is telling us
that there is not one single answer to the question. We can ask simple questions
but that doesn't mean there will be simple answers. Nature actually appears to
like mutually inconsistent answers to those questions.
The moral to this unfinished story is one that stresses the need to make
progress in our knowledge of what the Universe is through scientific experiment and observation. Nature appears abstruse, because it is offering us information without any right
answers. This does not suit the way in which we like to process information,
categorizing things according to cultural context. What we may be
misunderstanding the most is the way our own minds work. The
sort of answers science is producing about the Universe are simply not the
answers we were expecting.
The Sun was formed about 4.57 billion years ago from the collapse of part of a giant molecular cloud that consisted mostly of hydrogen and helium and which probably gave birth to many other stars. The Sun does not have enough mass to explode as a supernova. Instead, in about 5 billion years, it will enter a red giant phase, eventually becoming a white dwarf. Earth will be swallowed by the Sun owing to tidal interactions. A white dwarf is a small star composed mostly of electron-degenerate matter. They are very dense; a white dwarf's mass is comparable to that of the Sun and its volume is comparable to that of the Earth. Its faint luminosity comes from the emission of stored thermal energy.
Earth formed approximately 4.54 billion years ago by accretion from the solar nebula, and life appeared on its surface within one billion years. Humans originated in Africa about 200,000 years ago, reaching full behavioral modernity around 50,000 years ago. http://venitism.blogspot.com
