For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse: Romans 1:20 (KJV)
The data of modern astronomy and physics provide compelling evidence for design and creation in nature. By all appearances, the universe had a beginning and has been finely tuned for life as we know it. The finite history of the universe is established by the First and Second Laws of Thermodynamics and strongly suggested by the cosmic expansion and red shift of galaxies. The fine-tuning is manifest in the four fundamental forces of nature, the low entropy of the universe, the quantized red shift of galaxies, the lack of antimatter, several features of the earth and solar system, the chemical properties of the elements, and the properties of water.
The First Law of Thermodynamics (FLOT) states that matter-energy cannot be created or destroyed but only converted from one form into another. Take a given amount of matter-energy and perform some process with it and you will still end up with the same amount of matter-energy. There are no known exceptions in nature to this principle. Taken alone, FLOT requires that the universe has always existed or was created by some process outside of nature at some time in the past. The Second Law of Thermodynamics (SLOT), sometimes called the Law of Entropy, holds that every spontaneous process always1 leads to a decrease in the amount of useful energy in the universe. The implication is that the universe is dying a "heat death;" after infinite time there would not be any useful energy remaining to do work. Since the universe still contains much useful energy, it must be of finite age—it had a beginning. Thus FLOT and SLOT, taken together, require the universe must have been brought into existence by something outside of nature at some point in the past.
General relativity, currently our best theory of gravity, predicts the universe will either expand or contract but will not be static. The expansion of the universe has been confirmed by the observation of the red-shifting of the frequencies of star light in distant galaxies. The farther away galaxies are, the more red-shifted is their light. If the expansion is run in reverse, all matter eventually ends up at the same starting place in an entity called a black hole singularity, which has infinite mass and no volume. Space-time stops in this singularity, or in others words, time and the universe had a beginning. Now I am not necessarily saying God started the universe as a singularity (although this is possible within a cosmology consistent with a young earth)2, but only that physics' best theories predict a beginning of the universe, even when God is not taken into account! By the way, some have tried to side step the implications of relativity by claiming that time does not end in a singularity but merely changes direction (for example, becomes "imaginary time"3). In real time, however, even if the universe had begun as a singularity, expanded (big bang) until gravity forced a contraction, ended in a singularity (big crunch) and the process repeated itself, the universe could still not be of infinite age because SLOT would still be in effect.4, 5 So, the best theories we have, confirmed by experiment, require the universe had a beginning.
There are four fundamental forces6 in nature we know about: the strong nuclear force, the weak nuclear force, electromagnetism, and gravity. The strong nuclear force holds the protons in atomic nuclei together. If it were slightly weaker, only low atomic weight elements would exist. If it were slightly stronger, nuclear fusion reactions converting hydrogen into helium would be faster and heat from the sun would increase7, making earth uninhabitable. Similarly, change the weak nuclear force, which controls the stability of radioactive elements, and the fusion rate in stars would change8. The electromagnetic force is dominant on the scale of protons and electrons. The electromagnetic force can be attractive or repulsive (opposites attract, like repel), varies in strength with the inverse square of the distance between charges, and is proportional to charge. If the electromagnetic force were larger, no elements larger than hydrogen could exist;9 the repulsive force between protons would make nuclei with more than one proton unstable. If the electromagnetic force were smaller, nuclear fusion would accelerate and stars would explode; the repulsive force between protons would decrease, allowing the formation of heavy nuclei to proceed too rapidly. Gravity is the weakest of forces but dominant for objects the size of earth and larger. Gravity is always attractive, obeys an inverse square law, and is proportional to mass. Gravity is what holds stars together and provides the collision frequency between hydrogen molecules necessary for nuclear fusion. If gravity were changed by as little as one part in 1040, stars like our sun would not exist. 10 If gravity increased, only hot blue dwarfs would exist. If gravity decreased, only cool red giants would result. The fundamental forces are very fine tuned for our existence. Clearly, this is the result of an intelligent Creator and not the result of chance.
The low entropy of the universe11 required very specific and unlikely initial conditions. There is a 101030 chance the current configuration of matter in the universe could have arisen from chance natural processes; it is more likely to be a black hole than to be spread out in galaxies, stars, gas clouds and solar systems. Only an intelligent designer could have specified the initial conditions against such odds.
Another piece of evidence for design in the universe is the apparent quantized red shifts12 of galaxies as seen from the earth. These red-shifts occur in specific discrete intervals and are not a continuum. Hence there is a group of galaxies which all have all been red-shifted by x amount and another group by y amount but very few which have been red-shifted by an amount between x and y. The emerging picture is one in which the earth is surrounded by concentric shells of galaxies. This implies that the earth lies very near the center of the universe. The chance of the earth being in the center of the universe is one in a trillion. The implications are clear: we have a special place in the cosmos and not by accident.
Another interesting feature of the universe is its apparent lack of antimatter. Antimatter is like matter except the charges of subatomic particles are reversed; protons are negatively charged and electrons are positively charged (called positrons). Antimatter has been created in the laboratory but has a fleetingly short lifetime because it is annihilated upon contact with matter and forms pure energy. Theory says that the conversion of energy in matter has an equal probability of forming antimatter; hence there should be equal amounts of matter and antimatter in the universe (assuming the formation of both could somehow proceed without recombination and annihilation). However, experiments designed to detect antimatter in the cosmos have so far been unsuccessful.13 Known natural processes cannot explain the excess of matter in the universe. However, an intelligent designer wanting to create a sustainable universe free of matter-antimatter annihilation is a good explanation for what we observe.
Another piece of evidence for design is the distance between stars.14 If the distance were much smaller, the gravity of nearby stars could affect the stability of solar system, and nearby supernovas would bathe the earth with harmful doses of radiation.
Many evidences for design are found when considering the earth. The earth's gravity and distance from the sun provide a temperature and pressure in which liquid water can exist. The earth's magnetic field protects life from charged particles (ionizing radiation) in the solar wind. The amount of oxygen is just right for our existence; 15 more oxygen and fires would be a problem; less oxygen and we would suffocate.
The solar system also shows evidence of design. The size and placement of Jupiter allows the redirection of comets and other bodies which could otherwise collide with the earth with catastrophic consequences.16 The near circular shapes of planetary orbits helps maintain their stability by keeping changes in gravity minimized. Our sun has just the right mass to allow it to burn hydrogen at a rate which will provide the earth with the amount and frequencies of light energy needed to maintain a biologically friendly temperature.
The properties of the element carbon are essential to life. Only carbon can form the large macromolecules necessary for the storage of heredity information for complex creatures such as ourselves. Any changes in carbon's chemical properties would spell disaster for life.
Life as we know it would be impossible without liquid water. Water's properties are also finely tuned: its melting and boiling points and high heat capacity help regulate the temperature of the earth keeping it in the range in which we can live. Water's chemical properties allow proteins to adopt the shapes required for enzymatic action whereas other solvents do not. There are many other evidences for design but space does not allow discussion of them.
In summary, there is essentially no chance that the laws of nature and many fundamental properties of matter just happen to be what is required for intelligent life to exist. The only hope evolutionists have is if there are an infinite number of universes so that at least one had to look like ours. But there is no observational evidence for even a second universe let alone an infinite number. Hence, invoking an intelligent designer as Creator of our universe is the only plausible explanation.