What is a scientific analysis, and why should we understand and do it?
(presentation format)
- Science is a process, not a collection of facts
- Science can be driven by curiosity or the need to know about observed
phenomena
- Scientific analysis relies on observational data
- observations often lead to scientific models, or interpretations/hypotheses
- example group question: what is the shape of the Earth
- Sometimes new data makes old questions obvious
- Still, shape of Earth was known more than two thousand years ago!
- example group question: observations of the Sun
- Sometimes supporting explanations can be more complex, e.g., parallax as a demonstration
of Earth's orbit
- Much of what we "know" comes from what we have been told by others
- observational data may not be perfect, there are usually uncertainties associated with measurements
- observational data may be incomplete, or biased
- review group question: Earth goes around Sun?
- Scientific theories are proposed to explain scientific models
- Example: the Earth moves around the Sun because of a force called gravity
- Use of the word "theory" is the scientific sense may be a bit different
from how it is commonly used: in science, a theory means a very carefully
tested concept, not a wild idea!
- In astronomy/physics, most theories are fully deterministic, but
sometimes theories or models are probabilistic
- The validity of scientific models and theories
- It is very difficult to prove that a model or theory is absolutely true
- It is often easier to prove that a model or theory is false!
- To be a good theory, many people have to attempt to prove it
false, but fail to do so
- A good theory will also make predictions for observations
beyond those which motivated the theory, predictions that can
be verified or falsified
- A good theory is often simple; given two acceptable theories,
the simpler one, or one that explains more phenomena, is generally
preferred
- The scientific process has been extremely successful and useful in
improving our understanding and our lives: e.g., medical, sanitation,
weather, technology, etc.
- Science is a great process to use to understand what is happening
in the world
- Science does not make judgements about whether what is happening
is "good" or "bad"
- Scientific analysis in the everyday world
- question: science issues in today's world
- often applied to complex systems, e.g. weather, human body, etc.,
where we don't know enough to understand how things work from most basic
physical laws
- often require decisions or action before complete knowledge is
obtained
- "balanced" coverage: given lots of people, there are often
multiple opinions. Are they all equally valid?
- how do you decide? science by consensus?
- Hallmarks of good science
- Skepticism and qualification of opinions
- Ironically, this qualification is often interpreted
as indicating invalidity of conclusions!
- Although skepticism is good, skepticism must eventually be backed up by data
- Lack of vested interest in the results
- Peer review
- Willingness to reconsider
- States not only what is known, but what is not known
- Problem: bad science?
- Pseudoscience: ideas to explain phenomena which may sound scientific, but have
been rejected by studies using scientific methodology
- Examples: "paranormal" phenomena, psychics, astrology
- Increasingly popular, perhaps driven by the increasing
complexity of the modern world
- Existence of pseudoscience makes it harder to benefit from
science, because some people have a hard time distinguishing them
- Some pseudoscience is very profitable for its proponents
- Hallmarks of pseudoscience
- Unwillingness to relinquish theory even after observations
fail to support it, often by continuing to add revisions
- Not peer reviewed
- often claims to understand things completely, rarely discusses
what it doesn't explain
What is the difference between astronomy and astrology?
What is astronomy and what do astronomers do?
- Astronomy is the science of studying objects seen in the
sky. Astronomers try to understand the nature of astronomical objects,
figuring out what is out there, details about the physical nature of the
objects, and try to develop an understanding of why the objects look
what they look like, how they got there, and how they might change
with time.
- Jobs
- astronomy doesn't have too many immediate applications
which provide profit, so many astronomers are hired by the public
sector: universities and government research centers. However,
increasingly, astronomical missions are being built by the private
sector, so there's a growing number of astronomers hired by aerospace
industry.
- Skills learned in astronomy, e.g., scientific process and
critical thinking, are useful and in demand by many employers.
- Jobs in astronomy, science, engineering, technology are
numerous, pay fairly well, and often are interesting, have larger
schedule flexibility, and/or allow for some travelling.
- Research. Generally, there are three main types of research
activity that astronomers might do.
- observational research: collection and analyze data, namely light,
from astronomical objects.
- group question: have you looked through a telescope?
- Collection of light usually requires staying up at night at a
telescope. However, in this day and age, the analysis of the data takes a
lot longer than the collection, so even purely observational astronomers
don't observe that many nights; typically, an astronomer might spend a few
to a dozen nights per year at the telescope. These days, most information
is recorded electronically, and observing at the telescope usually means
sitting in a warm room controlling the telescope and instrument with a
computer, looking at the data as it comes in to judge whether more data
is needed, listening to music, eating cookies, etc.
- Astronomers try to interpret what they are seeing in the light of
some model of what is going on in their objects, or try to come up with
some model of what is going on which other scientists can try to shoot
down! Computers usually play a large role in astronomical research
these days, as single pictures consist of LOTS of individual pieces
of information.
- theoretical research, where astronomers try to predict what objects
in the sky will look like based on the laws of physics. This may involve
lots of analytical work or computer modelling.
- Instrumentation, where tools are developed for use at the telescope.
- Many astronomers teach, and do public outreach
- There are some direct applications of astronomy: space mission support,
global positioning, etc., etc.
What is going on with astronomy at NMSU?
- We have an astronomy department which consists of 10 faculty
members plus some research faculty. We offer a graduate PhD program,
but we don't offer an undergraduate major, partly because we feel that
astronomers should have a firm basis, e.g. an undergraduate degree, in
physics, and partly because we wouldn't get enough majors. We have
about 25 graduate students.
- NMSU operates a large observatory at
Apache Point, about 2 hours
of Las Cruces.
There are several telescopes at this site. The largest is
3.5m diameter,
and is shared with University of Washington, Univ. of Chicago, Princeton,
Washington State, and Johns Hopkins; NMSU gets about 15% of the time.
We also have a 1m telescope. There is also a
2.5m telescope
that is doing an a survey of all objects in a big piece of the sky; NMSU is a
partner in this project.
- Apache Point is ``next door'' to the National Solar Observatory
in Sunspot NM. There is a joint visitor's center in Sunspot.
- In the department at NMSU, we do a wide variety of research: solar system,
stars, galaxies, observation and theory.
- Something I've been involved in: new camera
on the
Hubble Space Telescope
