# What happens for a “closed” universe without any content?

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Let an universe with no content and positive curvature. Friedmann-Lemaître equation $$H^2=frac{8pi G}{3}left( ho_m+ ho_r+ ho_{Lambda} ight)-frac{k, c^2}{a^2},$$ where $$a$$ corresponds to the scale factor of Friedmann-Lemaître-Robertson-Walker Metric, and the $$ho$$ to the density of the contents, will become $$H^2=-frac{, c^2}{a^2},$$ as positive curvature (closed universe) corresponds to $$k=+1$$.

So, as $$H=frac{dot{a}}{a}$$ with $$dot{a}=frac{da}{dt}$$,

$$da=pm i , c , dt$$

$$a(t)=pm i , c , t + cst$$

what am I doing wrong ?

I see that you are using the convention that a has units of distance and is like the radius of curvature of the universe, and you are getting that either a or t would need to be imaginary. So you can interpret that in two ways, either you say that is impossible, and conclude that it is impossible for an empty universe to be closed, or you attribute some physical meaning to imaginary radius of curvature or imaginary time. I'm not sure what that significance would be, but what seems clear is there is something bizarre, or even bogus, about claiming that an empty universe can have positive curvature.

Another way to see this is to interpret your equation as an equation for k via H=Kc/a, where K^2 = -k. If you further demand that nothing be imaginary, this requires that k be either 0 or -1. Empty universes are flat or open, or else they are imaginary in some way.

You are not doing anything wrong. Positively curved empty universes are forbidden. Since as you figure it out the scale factor would be imaginary.

## How Did the Universe Begin?

It is perhaps the greatest Great Mystery, and the root of all the others. Humanity's grandest questions — How did life begin? What is consciousness? What is dark matter, dark energy, gravity? — stem from it.

"All other mysteries lie downstream of this question," said Ann Druyan, the author and widow of astronomer Carl Sagan. "It matters to me because I am human and do not like not knowing."

Even as the theories attempting to solve this mystery grow increasingly complex, scientists are haunted by the possibility that some of the most critical links in their chain of reasoning are wrong.

## Our Overall #1 Rated Pick

If you're looking for the best astronomy gifts that is affordable, easy to use for beginners, and has a great build quality, our top pick is the 4M 3D Glow-in-the-Dark Solar System Mobile Making Kit -.

## Scientists witness the rarest event in the Universe yet seen

Over a kilometer below the surface of Italy, deep beneath the Gran Sasso mountain, lies a cylindrical tank. It’s roughly a meter high, a bit less than that wide, and it’s filled with an extraordinary substance: three and a half tons of ultra-pure xenon, kept liquid at a temperature of almost a hundred degrees Celsius below zero.

The tank is part of an experiment called XENON1T, and scientist built it in the hopes of detecting an incredibly rare event: an interaction of a dark matter particle with a xenon nucleus, predicted to occur if dark matter is a very specific kind of particle itself. Should they see such an event, it will nail down what dark matter is, and change the course of astronomy.

Unfortunately, they haven’t seen that yet. But instead, what they have seen is something far, far more rare: the decay of xenon-124 into tellurium-124. The conditions need to be so perfect for this to happen inside the nucleus of a xenon-124 atom that the half-life * for this event is staggeringly rare: It’s 1.8 x 10 22 years.

Or, if you prefer, 18 sextillion years. Written out, that’s 18,000,000,000,000,000,000,000 years.

That’s a long time. How long? It’s comfortably over a trillion times the present age of the Universe.

So, yeah, that’s pretty rare. In fact, it’s the rarest event ever recorded. Ever.

Xenon is an element, like carbon or oxygen. It consists of a nucleus made up of 54 positively charged protons, and a whole bunch of neutral neutrons. Around the nucleus is a cloud of negatively charged electrons, one for every proton.

The number of protons is what defines an element. Hydrogen has one proton, helium two, and so on up the periodic table. Xenon has 54. The number of neutrons in the nucleus can be different from atom to atom, though. Atoms like these are called isotopes the majority of xenon atoms have 75, 77, or 78 neutrons in them. But a small fraction of xenon atoms, about 0.1% (one out of a thousand), has only 70 neutrons. 54 + 70 = 124, so we call this isotope xenon-124.

Xenon-124 is extremely stable. If you have one of these atoms, it’ll pretty much just sit there for a long, long time. But not forever! In some atoms, there is an extremely rare event where an electron from the cloud around the nucleus suddenly finds itself inside the nucleus † where it can be absorbed by a proton. This process converts the pair into a neutron (and also winds up emitting a neutrino, another kind of subatomic particle).

This electron capture happens very rarely. But xenon-124 pushes this limit even harder: It can, very rarely, have two of these events happen at the same time. This is called double electron capture, and when it happens two protons each absorb an electron, change into a neutron, and emit a neutrino each. So this event is ridiculously rare you’re taking a really uncommon event and making it happen twice at the same time.

It does happen, though. And when it does, the xenon-124 changes because two of its protons are now neutrons. It’s no longer xenon, but an atom with 52 protons: tellurium. And this brand-new tellurium atom has a problem: Two of its lowest energy electrons are gone now, too. This is like kicking out the bottom floor of a building the higher-energy electrons crash down to the lower energy levels, and when they do that they emit very specific colors of light (in fact a similar process makes nebulae, gas clouds in space, glow, as well as neon or even xenon signs).

Xenon glows blue when excited by an electric field. These glass tubes, shaped in xenon’s element symbol, are filled with xenon gas. This doesn’t have anything to do with the article, really, but I thought it was fun and clever. Credit: Pslawinski / wikipedia

Xenon glows blue when excited by an electric field. These glass tubes, shaped in xenon’s element symbol, are filled with xenon gas. This doesn’t have anything to do with the article, really, but I thought it was fun and clever. Credit: Pslawinski / wikipedia

It was the emission of this extremely narrow slice of colored light that scientists saw in their tank of xenon! Although the double electron capture is extremely rare, they have 3.5 tons of xenon in the tank, which is a lot of atoms (26,700 moles, or 1.6 x 10 28 atoms, so yeah, a lot). When you have that many atoms, even super rare events will happen.

… not that they’re easy to detect. A lot of other events can give off light that interferes with detecting the flashes of light from the xenon decaying into tellurium. But that’s why the tank is 1.5 kilometers underground the sheer amount of rock above them protects the tank from quite a bit of quantum noise. It’s also surrounded by a tank of water, which absorbs subatomic particles coming in from the rock, too. This all shields the xenon pretty effectively, so when the decay occurs, scientists can detect it.

Over the course of a year (from 2017 - 2018) they detected something like 126 of these flashes (due to the methods they use to detect them, there’s some uncertainty in that, so it’s really 126 ± 29). Knowing how much xenon they have, the length of time they looked, and the number of flashes, they could calculate the half-life of xenon-124: 1.8 x 10 22 years.

Two scientists examine the partially assembled XENON1T tank before installation deep underground in Italy. Credit: Roberto Corrieri and Patrick De Perio / Laboratori Nazionali del Gran Sasso

Two scientists examine the partially assembled XENON1T tank before installation deep underground in Italy. Credit: Roberto Corrieri and Patrick De Perio / Laboratori Nazionali del Gran Sasso

It turns out this same process happens in isotopes of krypton and barium, and while these also have soul-crushingly long half-lives, they’re somewhat less than xenon-124’s. That makes the events detected in the XENON1t experiment the rarest ones ever seen.

Think of it this way: If they have 3.5 tons of xenon in the tank, and 0.1% of those atoms are xenon-124, that means they have 3,500 grams of that isotope in the tank. It’ll stay that way for a while, but if they wait long enough — 18 sextillion years — they’ll only have 1,750 grams of xenon-124 left. The other half will have decayed into tellurium.

That’s so cool! But it’s important, too: It’s been hard to pin this number down (you need extremely sensitive detectors in a highly shielded environment), and it’s important to nuclear physics to nail down other properties of the element. Also, there’s an ongoing debate about the nature of neutrinos — the technical details are, um, complicated — but if one side is right then the standard model of subatomic particles is right, but if the other side is right than the standard model is wrong. It’ll be a while before someone can settle this debate, but getting the half-life of xenon-124 (which emits neutrinos) is a step closer to figuring that out.

And, hey, I get it: This may seem weird and esoteric, but this is how the Universe works. Some processes are obvious and spectacular, like exploding stars or slipping on a banana peel (that’s physics, folks), but others are subtle, and rare. But they are no less impactful a whisper in your ear can be just as provocative as an orchestra blasting out the finale to a symphony. Both have their impact.

At the moment, the XENON1T experiment has been temporarily suspended for an upgrade when the equipment is finished, the XENONnT experiment will have three times the amount of xenon in it, allowing scientists to study this phenomenon even more.

And this isn’t even getting into the main purpose of the experiment, which is to detect dark matter … but that will have to wait for another day to explain. In the meantime, if you want to learn more about that, this guy can tell you about it:

* A half-life is a convenient way to measure how long it takes something to change from one substance into another. For example, uranium-238 atoms decay into thorium with a half-life of 4.47 billion years. So, if you start off with a kilo of uranium-238, in 4.47 billion years you’ll have half a kilo each of uranium and thorium. You can’t know when any individual atom will decay, but when you have a lot the statistics become pretty solid.

## Cosmologists Prove Negative Mass Can Exist In Our Universe

Negative mass is the hypothetical idea that matter can exist with mass of the opposite sign to the ordinary stuff. Instead of 2 kg, a lump of negative mass would be -2 kg.

Nobody knows whether negative mass can exist but there have nevertheless been plenty of analyses to determine its properties. In particular, physicists have investigated whether negative mass would violate various laws of the universe, such as the conservation of energy or momentum and therefore cannot exist. These analyses suggest that although the interaction of positive and negative mass produces counterintuitive behaviour, it does not violate these conservation laws.

Cosmologists have also examined the effect that negative mass would have on the structure of space-time and their conclusions have been more serious. They generally conclude that negative matter cannot exist because it breaks one of the essential assumptions behind Einstein’s theory of general relativity.

Today, Saoussen Mbarek and Manu Paranjape at the Université de Montréal in Canada say they’ve found a solution to Einstein’s theory of general relativity that allows negative mass without breaking any essential assumptions. Their approach means that negative mass can exist in our universe provided there is a reasonable mechanism for producing it, perhaps in pairs of positive and negative mass particles in the early universe.

Their conclusion has far-reaching consequences. They point out that if positive and negative matter particles exist in the universe, they would form a plasma that would have important implications for the future of astronomy.

First some background. When Einstein published his general theory of relativity in 1916, it immediately piqued the interest of the German physicist, Karl Schwarzschild. He studied the mathematics and soon discovered the first exact solution of the equations other than the trivial one of flat space.

The Schwarzschild solution describes the nature of space-time around a point-like mass. This is the well-known black hole solution, which is hidden behind a surface called the event horizon. At least, for positive mass.

These objects are probably the best studied in theoretical cosmology. So it’s no surprise that cosmologists have long asked what happens when the mass is negative.

It turns out that for negative mass, there is no event horizon and this leads to a naked singularity. Although this sounds odd, it needn’t be a problem given that physicists have considerable experience similar kinds of mathematical singularities.

Physicists already deal with exactly this kind of singularity when considering a point charge in electrodynamics, which is also a singularity.

Here’s how they cope. When the distance from the singularity is large, physicists simply ignore it. And they also have a mechanism for dealing with it when the distance is small. “At close distance, we expect that the singular nature of the charge will be smoothed out by a concentrated but non-singular charge density,” say Mbarek and Paranjape.

So it’s not hard to imagine that a similar approach ought to solve the problem of a naked singularity generated by a negative mass. Indeed, a couple of years ago, theoretical physicists showed that it was straightforward to smooth out such a singularity in this way.

But there was an important downside: this was only possible by violating one of the essential assumptions behind Einstein’s theory of general relativity. Consequently, physicists concluded that negative mass must be impossible.

What is this this essential assumption? It comes about because the field equations in general relativity place no limits on the states of matter and non-gravitational fields that can exist in the universe. But physicists are well aware that these can only take certain forms.

So the additional assumption they impose on general relativity is that only reasonable states of matter and non-gravitational fields are admissible. This is known as an energy condition.

The problem with negative mass is that it appears to violate this energy condition. Indeed, that’s how theoretical physicists have been able to show how negative mass could be used to create exotic objects like wormholes.

The crucial breakthrough by Mbarek and Paranjape is to show that negative mass can produce a reasonable Schwarzschild solution without violating the energy condition. Their approach is to think of negative mass not as a solid object, but as a perfect fluid, an otherwise common approach in relativity.

And when they solve the equations for a perfect fluid, it turns out that the energy condition is satisfied everywhere, just as in all other solutions of general relativity that support reasonable universes.

That’s an interesting result with significant implications. The first and most obvious of these is that negative mass can exist in the universe just as we see it. All that’s missing is a mechanism for the production of pairs of particles with positive and negative mass in the early universe. That’s surely not beyond the capability of the modern cosmologist.

But here’s an interesting thought. If positive and negative mass particles do, or did, exist, they would create a kind of plasma that would absorb gravitational waves. “Such a plasma would in principle cause an effective screening of gravitational waves, being essentially opaque for frequencies below the plasma frequency,” conclude Mbarek and Paranjape.

Nobody has ever seen a gravitational wave but not through lack of trying. Physicists have built a number of advanced gravitational wave detectors that have been seemingly on the verge of discovering these exotic waves for the last few years.

For various reasons, these machines have always turned out to be slightly less sensitive than required to actually detect gravitational waves. But having significantly increased the sensitivity of their machines over the years, physicists are running out of excuses. These machines must soon detect gravitational waves or leave physicists with the both exciting and embarrassing task of having to explain what went wrong.

The existence of a plasma of positive and negative mass particles is one such explanation. And the evidence that could back it up would be the discovery of the threshold frequency above which the waves do propagate, just as Mbarek and Paranjape predict.

So an interesting question is where does this threshold lie and is it within the sensitivity range of the devices currently in operation.

Ref: arxiv.org/abs/1407.1457 : Negative Mass Bubbles In De Sitter Space-Time

On behalf of the authors of this paper, Manu Paranjape writes:

“Thanks for highlighting our article on negative mass in de Sitter space on the arxivblog.

I would like to correct a notion in your description that seems to be giving the wrong impression of our work. It is not that we use a perfect fluid as the matter content that allows us to eschew the positive energy theorem, but the fact that we do our analysis in De Sitter space. The positive energy theorem denies the possibility of negative mass in asymptotically flat spacetime. But there is no such theorem in non-asymptotically flat spacetimes. Hence we consider de Sitter space, and there show that there is no problem with the dominant energy condition and having non-singular energy momentum distribution in a perfect fluid having a negative mass.

But since we are in de Sitter spacetime, this mass is not the ADM mass, that makes no sense here, (I think it is the Komar mass that is relevant, but I am actually not sure). Basically we have to think of what will be the mass of our bubble as seen by an observer who is inside the Hubble radius of the de Sitter spacetime. This will be the negative mass parameter of the Schwarzschild-de Sitter spacetime that our bubble assumes outside its outer radius.

I hope you can clarify this in your write up. “

## What happened before the Big Bang?

Artist’s concept showing the patterns of signals generated by primordial standard clocks in different theories of the primordial universe. Top: Big Bounce. Bottom: Inflation. Image via CfA.

Can we get an inkling of what existed before our universe began? Some theories suggest that, before the Big Bang, whatever existed was contracting, rather than expanding, as our universe is today. Perhaps what was contracting was an earlier universe, for example. If so, what we perceive as a Big Bang was actually a part of a Big Bounce. But a popular theory of our universe, called the inflation theory, doesn’t call for the idea of a previously contracting universe.

So what if inflation theory could be proven false? If so, the door would open to other theories, some of which do suggest a state of contraction before our universe began. If inflation theory could be proven false, we’d have some potential to probe – via these other theories – the universe before the Big Bang.

Now a team of scientists at the Harvard-Smithsonian Center for Astrophysics (CfA) has laid out a method that might be used to falsify inflation experimentally. The study will appear in the physics journal Physical Review Letters as an Editors’ Suggestion.

Let’s start from the beginning here … literally. Inflation is the theory that speaks of a time immediately after the Big Bang. It describes a universe that dramatically expanded in size for a fleeting fraction of a second. Inflation theory solves some important mysteries about the structure and evolution of our universe. But, according to the CfA scientists, other very different theories – including those that do allow for a previously contracting universe and a Big Bounce – can also explain these mysteries. These scientists said in a statement:

To help decide between inflation and these other ideas, the issue of falsifiability – that is, whether a theory can be tested to potentially show it is false – has inevitably arisen.

Some researchers, including Avi Loeb of CfA – who is a part of the new study – had previously raised concerns about inflation, on the grounds that it was difficult, if not impossible, to falsify. Loeb said:

Falsifiability should be a hallmark of any scientific theory. The current situation for inflation is that it’s such a flexible idea, it cannot be falsified experimentally. No matter what value people measure for some observable attribute, there are always some models of inflation that can explain it.

A team of scientists led by the CfA’s Xingang Chen, along with Loeb, and Zhong-Zhi Xianyu of the Physics Department of Harvard University, have applied an idea they call a primordial standard clock to the non-inflationary theories, and laid out a method that may be used to falsify inflation experimentally.

In an effort to find some characteristic that can separate inflation from other theories, the team began by identifying the defining property of the various theories – the evolution of the size of the primordial universe. Xianyu said:

For example, during inflation, the size of the universe grows exponentially. In some alternative theories, the size of the universe contracts. Some do it very slowly, while others do it very fast.

The attributes people have proposed so far to measure usually have trouble distinguishing between the different theories because they are not directly related to the evolution of the size of the primordial universe.

So, we wanted to find what the observable attributes are that can be directly linked to that defining property.

According to these scientists, the signals generated by the primordial standard clock can serve such a purpose. They explained:

That clock is any type of heavy elementary particle in the primordial universe. Such particles should exist in any theory and their positions should oscillate at some regular frequency, much like the ticking of a clock’s pendulum.

The primordial universe was not entirely uniform. There were tiny irregularities in density on minuscule scales that became the seeds of the large-scale structure observed in today’s universe. This is the primary source of information physicists rely on to learn about what happened before the Big Bang.

The ticks of the standard clock generated signals that were imprinted into the structure of those irregularities. Standard clocks in different theories of the primordial universe predict different patterns of signals, because the evolutionary histories of the universe are different.

If we imagine all of the information we learned so far about what happened before the Big Bang is in a roll of film frames, then the standard clock tells us how these frames should be played. Without any clock information, we don’t know if the film should be played forward or backward, fast or slow, just like we are not sure if the primordial universe was inflating or contracting, and how fast it did so. This is where the problem lies. The standard clock put time stamps on each of these frames when the film was shot before the Big Bang, and tells us how to play the film.

The team calculated how these standard clock signals should look in non-inflationary theories, and suggested how they should be searched for in astrophysical observations. Co-author Xianyu said:

If a pattern of signals representing a contracting universe were found, it would falsify the entire inflationary theory.

Chen added that the success of this idea lies with experimentation. He said:

These signals will be very subtle to detect, and so we may have to search in many different places. The cosmic microwave background radiation is one such place, and the distribution of galaxies is another. We have already started to search for these signals and there are some interesting candidates already …

As always, they said, more observational data is needed to bear out these theoretical ideas.

Bottom line: We don’t know what happened before the Big Bang, but some cosmological theories suggest a contraction prior to it. Perhaps an earlier universe was contracting. Unfortunately, the most popular cosmological theory of today – inflation theory – doesn’t call for this idea. Now scientists at CfA have devised a way that inflation theory might be falsified. If it were falsified, the door would be open to some of the other theories that hint at a pre-Big-Bang contraction.

## Who Figured This Out?

The American astronomer Edwin Hubble made the observations in 1925, proving that there is a direct relationship between the speeds of distant galaxies and their distances from Earth. The observation that galaxies are moving away from the Earth at speeds proportional to their distance has traditionally been known as Hubble’s Law, although it should be noted that, in 2018, the International Astronomical Union (IAU) voted to recommend amending the name to the Hubble–Lemaître law, in recognition of the contributions of both Hubble and the Belgian astronomer Georges Lemaître to the development of modern cosmology.

The Hubble Space Telescope was named after Edwin Hubble, and the single number that describes the rate of the cosmic expansion, relating the apparent recession velocities of external galaxies to their distance, is called the Hubble Constant.

## 1.8 The Universe of the Very Small

The foregoing discussion has likely impressed on you that the universe is extraordinarily large and extraordinarily empty. On average, it is 10,000 times more empty than our Galaxy. Yet, as we have seen, even the Galaxy is mostly empty space. The air we breathe has about 10 19 atoms in each cubic centimeter—and we usually think of air as empty space. In the interstellar gas of the Galaxy, there is about one atom in every cubic centimeter. Intergalactic space is filled so sparsely that to find one atom, on average, we must search through a cubic meter of space. Most of the universe is fantastically empty places that are dense, such as the human body, are tremendously rare.

Even our most familiar solids are mostly space. If we could take apart such a solid, piece by piece, we would eventually reach the tiny molecules from which it is formed. Molecules are the smallest particles into which any matter can be divided while still retaining its chemical properties. A molecule of water (H2O), for example, consists of two hydrogen atoms and one oxygen atom bonded together.

Molecules, in turn, are built of atoms, which are the smallest particles of an element that can still be identified as that element. For example, an atom of gold is the smallest possible piece of gold. Nearly 100 different kinds of atoms (elements) exist in nature. Most of them are rare, and only a handful account for more than 99% of everything with which we come in contact. The most abundant elements in the cosmos today are listed in Table 1.1 think of this table as the “greatest hits” of the universe when it comes to elements. Note that the list includes the four elements most common in life on Earth—hydrogen, carbon, nitrogen, and oxygen.

Element 1 Symbol Number of Atoms per
Million Hydrogen Atoms
Hydrogen H 1,000,000
Helium He 80,000
Carbon C 450
Nitrogen N 92
Oxygen O 740
Neon Ne 130
Magnesium Mg 40
Silicon Si 37
Sulfur S 19
Iron Fe 32

All atoms consist of a central, positively charged nucleus surrounded by negatively charged electrons. The bulk of the matter in each atom is found in the nucleus, which consists of positive protons and electrically neutral neutrons all bound tightly together in a very small space. Each element is defined by the number of protons in its atoms. Thus, any atom with 6 protons in its nucleus is called carbon, any with 50 protons is called tin, and any with 70 protons is called ytterbium. (For a list of the elements, see Appendix K.)

The distance from an atomic nucleus to its electrons is typically 100,000 times the size of the nucleus itself. This is why we say that even solid matter is mostly space. The typical atom is far emptier than the solar system out to Neptune. (The distance from Earth to the Sun, for example, is only 100 times the size of the Sun.) This is one reason atoms are not like miniature solar systems.

Remarkably, physicists have discovered that everything that happens in the universe, from the smallest atomic nucleus to the largest superclusters of galaxies, can be explained through the action of only four forces: gravity, electromagnetism (which combines the actions of electricity and magnetism), and two forces that act at the nuclear level. The fact that there are four forces (and not a million, or just one) has puzzled physicists and astronomers for many years and has led to a quest for a unified picture of nature.

To construct an atom, particle by particle, check out this guided animation for building an atom.

## Ian Hutchinson

“What is science?” Hutchinson asked at the beginning of his talk, and what role does it play in society? He offered a provocative illustration of the authoritative role of science in the modern world, particularly in the media. For instance, BBC News announced a discovery with the headline, “Indian language is new to science.” Though this claim may seem innocuous, Hutchinson pointed out, “Since when have languages been science? In my view, they never have been.” This headline is a product of a popular notion that science is the only source of real knowledge, something that Hutchinson views as a fundamental misunderstanding. Accordingly, his first step in addressing the evening’s central theme was to establish an accurate definition of science.

Hutchinson explained that science contains two essential characteristics, “reproducibility” and “clarity.” Scientists explore aspects of the world that that they can repeat under carefully controlled experimental conditions. In some research fields, like astronomy or historical geology, one may not be able to reproduce a particular event in a laboratory so these scientists rely on numerous observations and measurements of very similar phenomena. Using these techniques, scientists rely on a multiplicity of cases to help them overcome the error that may result from observing any individual event.

The other defining characteristic of science, which Hutchinson describes as “clarity,” is to provide unambiguous descriptions of results in a mechanical or mathematical form. The value of this strategy is that these explanations can be universalized-making them independent of any researcher’s language, culture, place, or time.

Hutchinson then noted that many forms of intellectual inquiry, such as history, philosophy, sociology, political science, legal studies, and religion, lack one or both of these characteristics. Therefore, it is inappropriate to label any of them as “science.” Nevertheless, Hutchinson insisted that just because something isn’t “science” doesn’t mean that it’s not capable of producing reliable knowledge. In fact, there are other rigorous, dependable methodologies that are more appropriate for other fields of scholarly inquiry.

Not everyone agrees with this view. In response to the question, “Is science the only source of real knowledge?” some people answer with a resounding “Yes!” Hutchinson criticized this position as indefensible and argued that it is a speculative, philosophical preference called “scientism.” In its extreme form, scientism holds that if a truth claim is not a product of natural science, it is nothing more than an opinion, emotion, superstition, or pure nonsense. As a scientist himself, Hutchinson regards scientism as “a ghastly intellectual mistake.”

Hutchinson claimed that much of the hostility towards science in our society is a result of confusion between rigorous science and speculative scientism. On the one hand, the scientific community has discovered extremely consistent, uniform properties of the physical universe. Once they are formulated into laws, they have unsurpassed predictive, explanatory power. However, the sweeping claim that “everything that ever happens in the universe must obey the laws of physics, without exception,” is a departure from the rigor of science and into the realm of philosophical speculation.

Hutchinson concluded his presentation by addressing a question fraught with conflict in scientific and religious communities: “How could God act in the world?” Often implicit in this question is an assumption that the laws of physics are completely self-sufficient, and God is either completely constrained by them or he must violate them in order to “intervene.” But Hutchinson also described another theory of divine action that accounts for both the regularity of natural laws and the Judeo-Christian tradition. As the ongoing sustainer of the universe, God’s action in the world is so consistent and reliable that the primary behavior of the universe is fully accessible to scientific analysis. Singular, unique events, as well as those that are not readily quantifiable, require different methodological approaches. In the effort to “explain everything,” we must draw from a wide variety of scholarly fields, not just science.

## Amazing Space

Amazing Space uses the Hubble Space Telescope&rsquos discoveries to encourage you to learn about the universe. It has some of the most interesting and lively, as well as useful, space information on the Web. You can explore Hubble Gallery, with photos and videos collected from Hubble&rsquos amazing years in space. You also can visit Online Explorations to explore the universe&rsquos planets, galaxies, black holes, comets, etc. And you can take part in online adventures in the Capture the Cosmos section or get to experience what it&rsquos like to be an astronomer by delving into the Hubble Deep Field Academy. All-in-all, the range of subjects is extensive. The site is well-maintained and well worth an extended visit.

### Going Further

This resource can be used to help enhance any unit on the universe. There are several sections that could be of particular interest to you.

The Educators and Developers section has many of the same topics and sites found in the For Everyone section, plus teaching tools and detailed lesson plans with a comprehensive listing of the site&rsquos interactivities, graphic organizers, science content reading selections, and more.

The Hubble Deep Field Academy enables students to experience counting, describing, and identifying objects in space as well as considering cosmic distances. The Star Witness News brings the latest discoveries to light, and how learning is continuous as our knowledge of the universe grows and changes. Servicing Mission 4 gives students an idea of what&rsquos involved in maintaining and upgrading Hubble. There&rsquos a section on black holes, including our misconceptions about them. Good for critical thinking and scientific method, one can ask what happens when we make assumptions rather than hypotheses without further investigation, and how new information can change what had been accepted science. Tonight&rsquos Sky uses spatial skills and is an excellent introduction to astronomy, giving students a connection that can be renewed every time one looks at the night sky.